Squashed commit of the following:

    Merge changes from update_merged_S3_HDFS branch into develop.

commit d5034315aea88629929ac0c9c59ebfafd5f21a31
Merge: 9c48823 d3fdcd8
Author: Larry Knox <lrknox@hdfgroup.org>
Date:   Thu Jul 25 08:24:53 2019 -0500

    Merge branch 'develop' into update_merged_S3_HDFS

1 files changed, 2813 insertions, 0 deletions

diff --git a/test/s3comms.c b/test/s3comms.c
new file mode 100644
index 0000000..71d93c2
--- /dev/null
+++ b/test/s3comms.c
@@ -0,0 +1,2813 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Read-Only S3 Virtual File Driver (VFD)                                    *
+ * Copyright (c) 2017-2018, The HDF Group.                                   *
+ *                                                                           *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * NOTICE:                                                                   *
+ * All information contained herein is, and remains, the property of The HDF *
+ * Group. The intellectual and technical concepts contained herein are       *
+ * proprietary to The HDF Group. Dissemination of this information or        *
+ * reproduction of this material is strictly forbidden unless prior written  *
+ * permission is obtained from The HDF Group.                                *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Purpose:    Unit tests for the S3 Communications (s3comms) module.
+ *
+ * Programmer: Jacob Smith <jake.smith@hdfgroup.org>
+ *             2017-10-11
+ */
+
+#include "h5test.h"
+#include "H5FDs3comms.h"
+#include "H5MMprivate.h" /* memory management */
+
+/*****************************************************************************
+ *
+ * FILE-LOCAL TESTING MACROS
+ *
+ * Purpose:
+ *
+ *     1) Upon test failure, goto-jump to single-location teardown in test
+ *        function. E.g., `error:` (consistency with HDF corpus) or
+ *        `failed:` (reflects purpose).
+ *            >>> using "error", in part because `H5E_BEGIN_TRY` expects it.
+ *     2) Increase clarity and reduce overhead found with `TEST_ERROR`.
+ *        e.g., "if(somefunction(arg, arg2) < 0) TEST_ERROR:"
+ *        requires reading of entire line to know whether this if/call is
+ *        part of the test setup, test operation, or a test unto itself.
+ *     3) Provide testing macros with optional user-supplied failure message;
+ *        if not supplied (NULL), generate comparison output in the spirit of
+ *        test-driven development. E.g., "expected 5 but was -3"
+ *        User messages clarify test's purpose in code, encouraging description
+ *        without relying on comments.
+ *     4) Configurable expected-actual order in generated comparison strings.
+ *        Some prefer `VERIFY(expected, actual)`, others
+ *        `VERIFY(actual, expected)`. Provide preprocessor ifdef switch
+ *        to satifsy both parties, assuming one paradigm per test file.
+ *        (One could #undef and redefine the flag through the file as desired,
+ *         but _why_.)
+ *        Provided as courtesy, per consideration for inclusion in the library
+ *        proper.
+ *
+ *     Macros:
+ *
+ *         JSVERIFY_EXP_ACT - ifdef flag, configures comparison order
+ *         FAIL_IF()        - check condition
+ *         FAIL_UNLESS()    - check _not_ condition
+ *         JSVERIFY()       - long-int equality check; prints reason/comparison
+ *         JSVERIFY_NOT()   - long-int inequality check; prints
+ *         JSVERIFY_STR()   - string equality check; prints
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *****************************************************************************/
+
+
+/*----------------------------------------------------------------------------
+ *
+ * ifdef flag: JSVERIFY_EXP_ACT
+ *
+ * JSVERIFY macros accept arguments as (EXPECTED, ACTUAL[, reason])
+ *   default, if this is undefined, is (ACTUAL, EXPECTED[, reason])
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY_EXP_ACT 1L
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: JSFAILED_AT()
+ *
+ * Purpose:
+ *
+ *     Preface a test failure by printing "*FAILED*" and location to stdout
+ *     Similar to `H5_FAILED(); AT();` from h5test.h
+ *
+ *     *FAILED* at somefile.c:12 in function_name()...
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSFAILED_AT() {                                                   \
+    HDprintf("*FAILED* at %s:%d in %s()...\n", __FILE__, __LINE__, FUNC); \
+}
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: FAIL_IF()
+ *
+ * Purpose:
+ *
+ *     Make tests more accessible and less cluttered than
+ *         `if (thing == otherthing()) TEST_ERROR`
+ *         paradigm.
+ *
+ *     The following lines are roughly equivalent:
+ *
+ *         `if (myfunc() < 0) TEST_ERROR;` (as seen elsewhere in HDF tests)
+ *         `FAIL_IF(myfunc() < 0)`
+ *
+ *     Prints a generic "FAILED AT" line to stdout and jumps to `error`,
+ *     similar to `TEST_ERROR` in h5test.h
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-23
+ *
+ *----------------------------------------------------------------------------
+ */
+#define FAIL_IF(condition) \
+if (condition) {           \
+    JSFAILED_AT()          \
+    goto error;            \
+}
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: FAIL_UNLESS()
+ *
+ * Purpose:
+ *
+ *     TEST_ERROR wrapper to reduce cognitive overhead from "negative tests",
+ *     e.g., "a != b".
+ *
+ *     Opposite of FAIL_IF; fails if the given condition is _not_ true.
+ *
+ *     `FAIL_IF( 5 != my_op() )`
+ *     is equivalent to
+ *     `FAIL_UNLESS( 5 == my_op() )`
+ *     However, `JSVERIFY(5, my_op(), "bad return")` may be even clearer.
+ *         (see JSVERIFY)
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define FAIL_UNLESS(condition) \
+if (!(condition)) {            \
+    JSFAILED_AT()              \
+    goto error;                \
+}
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: JSERR_LONG()
+ *
+ * Purpose:
+ *
+ *     Print an failure message for long-int arguments.
+ *     ERROR-AT printed first.
+ *     If `reason` is given, it is printed on own line and newlined after
+ *     else, prints "expected/actual" aligned on own lines.
+ *
+ *     *FAILED* at myfile.c:488 in somefunc()...
+ *     forest must be made of trees.
+ *
+ *     or
+ *
+ *     *FAILED* at myfile.c:488 in somefunc()...
+ *       ! Expected 425
+ *       ! Actual   3
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSERR_LONG(expected, actual, reason) {           \
+    JSFAILED_AT()                                        \
+    if (reason!= NULL) {                                 \
+        HDprintf("%s\n", (reason));                      \
+    } else {                                             \
+        HDprintf("  ! Expected %ld\n  ! Actual   %ld\n", \
+                  (long)(expected), (long)(actual));     \
+    }                                                    \
+}
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: JSERR_STR()
+ *
+ * Purpose:
+ *
+ *     Print an failure message for string arguments.
+ *     ERROR-AT printed first.
+ *     If `reason` is given, it is printed on own line and newlined after
+ *     else, prints "expected/actual" aligned on own lines.
+ *
+ *     *FAILED*  at myfile.c:421 in myfunc()...
+ *     Blue and Red strings don't match!
+ *
+ *     or
+ *
+ *     *FAILED*  at myfile.c:421 in myfunc()...
+ *     !!! Expected:
+ *     this is my expected
+ *     string
+ *     !!! Actual:
+ *     not what I expected at all
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSERR_STR(expected, actual, reason) {           \
+    JSFAILED_AT()                                       \
+    if ((reason) != NULL) {                             \
+        HDprintf("%s\n", (reason));                     \
+    } else {                                            \
+        HDprintf("!!! Expected:\n%s\n!!!Actual:\n%s\n", \
+                 (expected), (actual));                 \
+    }                                                   \
+}
+
+#ifdef JSVERIFY_EXP_ACT
+/* VERIFY rountines with paramter order (<expected>, <actual> [, <msg> ])
+ */
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: JSVERIFY()
+ *
+ * Purpose:
+ *
+ *     Verify that two long integers are equal.
+ *     If unequal, print failure message
+ *     (with `reason`, if not NULL; expected/actual if NULL)
+ *     and jump to `error` at end of function
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY(expected, actual, reason)     \
+if ((long)(actual) != (long)(expected)) {      \
+    JSERR_LONG((expected), (actual), (reason)) \
+    goto error;                                \
+} /* JSVERIFY */
+
+#if 0 /* UNUSED */
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: JSVERIFY_NOT()
+ *
+ * Purpose:
+ *
+ *     Verify that two long integers are _not_ equal.
+ *     If equal, print failure message
+ *     (with `reason`, if not NULL; expected/actual if NULL)
+ *     and jump to `error` at end of function
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY_NOT(expected, actual, reason) \
+if ((long)(actual) == (long)(expected)) {      \
+    JSERR_LONG((expected), (actual), (reason)) \
+    goto error;                                \
+} /* JSVERIFY_NOT */
+#endif /* JSVERIFY_NOT unused */
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Macro: JSVERIFY_STR()
+ *
+ * Purpose:
+ *
+ *     Verify that two strings are equal.
+ *     If unequal, print failure message
+ *     (with `reason`, if not NULL; expected/actual if NULL)
+ *     and jump to `error` at end of function
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-24
+ *
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY_STR(expected, actual, reason) \
+if (strcmp((actual), (expected)) != 0) {       \
+    JSERR_STR((expected), (actual), (reason)); \
+    goto error;                                \
+} /* JSVERIFY_STR */
+
+
+#else
+/* JSVERIFY_EXP_ACT not defined
+ *
+ * Repeats macros above, but with actual/expected parameters reversed.
+ */
+
+
+/*----------------------------------------------------------------------------
+ * Macro: JSVERIFY()
+ * See: JSVERIFY documentation above.
+ * Programmer: Jacob Smith
+ *             2017-10-14
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY(actual, expected, reason)      \
+if ((long)(actual) != (long)(expected)) {       \
+    JSERR_LONG((expected), (actual), (reason)); \
+    goto error;                                 \
+} /* JSVERIFY */
+
+#if 0 /* UNUSED */
+
+/*----------------------------------------------------------------------------
+ * Macro: JSVERIFY_NOT()
+ * See: JSVERIFY_NOT documentation above.
+ * Programmer: Jacob Smith
+ *             2017-10-14
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY_NOT(actual, expected, reason) \
+if ((long)(actual) == (long)(expected)) {      \
+    JSERR_LONG((expected), (actual), (reason)) \
+    goto error;                                \
+} /* JSVERIFY_NOT */
+#endif /* JSVERIFY_NOT unused */
+
+
+/*----------------------------------------------------------------------------
+ * Macro: JSVERIFY_STR()
+ * See: JSVERIFY_STR documentation above.
+ * Programmer: Jacob Smith
+ *             2017-10-14
+ *----------------------------------------------------------------------------
+ */
+#define JSVERIFY_STR(actual, expected, reason) \
+if (strcmp((actual), (expected)) != 0) {       \
+    JSERR_STR((expected), (actual), (reason)); \
+    goto error;                                \
+} /* JSVERIFY_STR */
+
+#endif /* ifdef/else JSVERIFY_EXP_ACT */
+
+
+#ifdef H5_HAVE_ROS3_VFD
+
+#define S3_TEST_PROFILE_NAME "ros3_vfd_test"
+
+#define S3_TEST_RESOURCE_TEXT_RESTRICTED "t8.shakespeare.txt"
+#define S3_TEST_RESOURCE_TEXT_PUBLIC "Poe_Raven.txt"
+#define S3_TEST_RESOURCE_MISSING "missing.csv"
+
+#define S3_TEST_RUN_TIMEOUT 0 /* run tests that might hang */
+#define S3_TEST_MAX_URL_SIZE 256 /* char array size */
+
+/* Global variables for aws test profile.
+ * An attempt is made to read ~/.aws/credentials and ~/.aws/config upon test
+ * startup -- if unable to open either file or cannot load region, id, and key,
+ * tests connecting with S3 will not be run
+ */
+static int     s3_test_credentials_loaded               = 0;
+static char    s3_test_aws_region[16]                   = "";
+static char    s3_test_aws_access_key_id[64]            = "";
+static char    s3_test_aws_secret_access_key[128]       = "";
+static char    s3_test_bucket_url[S3_TEST_MAX_URL_SIZE] = "";
+static hbool_t s3_test_bucket_defined                   = FALSE;
+
+#endif /* H5_HAVE_ROS3_VFD */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_macro_format_credential()
+ *
+ * Purpose:
+ *
+ *     Demonstrate that the macro `S3COMMS_FORMAT_CREDENTIAL`
+ *     performs as expected.
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-19
+ *
+ *----------------------------------------------------------------------------
+ */
+static herr_t
+test_macro_format_credential(void)
+{
+    /************************
+     * test-local variables *
+     ************************/
+
+#ifdef H5_HAVE_ROS3_VFD
+    char       dest[256];
+    const char access[]   = "AKIAIOSFODNN7EXAMPLE";
+    const char date[]     = "20130524";
+    const char region[]   = "us-east-1";
+    const char service[]  = "s3";
+    const char expected[] =
+            "AKIAIOSFODNN7EXAMPLE/20130524/us-east-1/s3/aws4_request";
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("test_macro_format_credential");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    FAIL_IF( S3COMMS_MAX_CREDENTIAL_SIZE <
+             S3COMMS_FORMAT_CREDENTIAL(dest, access, date, region, service) )
+
+    JSVERIFY_STR( expected, dest, NULL )
+
+    PASSED();
+    return 0;
+#endif /* H5_HAVE_ROS3_VFD */
+
+error:
+    return -1;
+
+} /* test_macro_format_credential */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_aws_canonical_request()
+ *
+ * Purpose:
+ *
+ *     Demonstrate the construction of a Canoncial Request (and Signed Headers)
+ *
+ *     Elided / not yet implemented:
+ *         Query strings
+ *         request "body"
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-04
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_aws_canonical_request(void)
+{
+    /*************************
+     * test-local structures *
+     *************************/
+
+#ifdef H5_HAVE_ROS3_VFD
+    struct header {
+        const char *name;
+        const char *value;
+    };
+
+    struct testcase {
+        const char    *exp_request;
+        const char    *exp_headers;
+        const char    *verb;
+        const char    *resource;
+        unsigned int   listsize;
+        struct header  list[5];
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase  cases[]   = {
+        {   "GET\n/some/path.file\n\nhost:somebucket.someserver.somedomain\nrange:bytes=150-244\n\nhost;range\ne3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+            "host;range",
+            "GET",
+            "/some/path.file",
+            2,
+            {   {"Range", "bytes=150-244"},
+                {"Host", "somebucket.someserver.somedomain"},
+            },
+        },
+        {   "HEAD\n/bucketpath/myfile.dat\n\nhost:place.domain\nx-amz-content-sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\nx-amz-date:19411207T150803Z\n\nhost;x-amz-content-sha256;x-amz-date\ne3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+            "host;x-amz-content-sha256;x-amz-date",
+            "HEAD",
+            "/bucketpath/myfile.dat",
+            3,
+            {   {"x-amz-content-sha256", "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"},
+                {"host", "place.domain"},
+                {"x-amz-date", "19411207T150803Z"},
+            }
+        },
+        {   "PUT\n/\n\n\n\ne3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+            "",
+            "PUT",
+            "/",
+            0,
+            {{"",""},}, /* unused; satisfies compiler */
+        },
+    }; /* struct testcase cases[] */
+    struct testcase *C         = NULL;
+    char             cr_dest[512];     /* canonical request */
+    hrb_t           *hrb       = NULL; /* http request buffer object */
+    unsigned int     i         = 0;    /* looping/indexing */
+    unsigned int     j         = 0;    /* looping/indexing */
+    hrb_node_t      *node      = NULL; /* http headers list pointer */
+    unsigned int     n_cases   = 3;
+    char             sh_dest[64];       /* signed headers */
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("test_aws_canonical_request");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (i = 0; i < n_cases; i++) {
+        /* pre-test bookkeeping
+         */
+        C = &cases[i];
+        for (j = 0; j < 256; j++) { cr_dest[j] = 0; } /* zero request buffer */
+        for (j = 0; j <  64; j++) { sh_dest[j] = 0; } /* zero headers buffer */
+
+        /* create HTTP request object with given verb, resource/path
+         */
+        hrb = H5FD_s3comms_hrb_init_request(C->verb,
+                                            C->resource,
+                                            "HTTP/1.1");
+        HDassert(hrb->body == NULL);
+
+        /* Create headers list from test case input
+         */
+        for (j = 0; j < C->listsize; j++) {
+            FAIL_IF( FAIL ==
+                     H5FD_s3comms_hrb_node_set(
+                             &node,
+                             C->list[j].name,
+                             C->list[j].value));
+        }
+
+        hrb->first_header = node;
+
+        /* test
+         */
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_aws_canonical_request(cr_dest, sh_dest, hrb),
+                  " unable to compose canonical request" )
+        JSVERIFY_STR( C->exp_headers, sh_dest, NULL )
+        JSVERIFY_STR( C->exp_request, cr_dest, NULL )
+
+        /* tear-down
+         */
+        while (node != NULL)
+            FAIL_IF( FAIL ==
+                     H5FD_s3comms_hrb_node_set(&node, node->name, NULL));
+        HDassert(NULL == node);
+        FAIL_IF( FAIL == H5FD_s3comms_hrb_destroy(&hrb));
+        HDassert(NULL == hrb);
+
+    } /* for each test case */
+
+    /***************
+     * ERROR CASES *
+     ***************/
+
+     /*  malformed hrb and/or node-list
+      */
+    JSVERIFY( FAIL, H5FD_s3comms_aws_canonical_request(cr_dest, sh_dest, NULL),
+              "http request object cannot be null" )
+
+    hrb = H5FD_s3comms_hrb_init_request("GET", "/", "HTTP/1.1");
+    JSVERIFY( FAIL, H5FD_s3comms_aws_canonical_request(NULL, sh_dest, hrb),
+              "canonical request destination cannot be NULL" )
+
+    JSVERIFY( FAIL, H5FD_s3comms_aws_canonical_request(cr_dest, NULL, hrb),
+              "signed headers destination cannot be null" )
+
+    FAIL_IF( FAIL == H5FD_s3comms_hrb_destroy(&hrb) )
+    HDassert( NULL == hrb );
+
+    PASSED();
+    return 0;
+
+error:
+
+    if (node != NULL) {
+        while (node != NULL)
+               (void)H5FD_s3comms_hrb_node_set(&node, node->name, NULL);
+        HDassert( node == NULL );
+    }
+    if (hrb != NULL)
+        (void)H5FD_s3comms_hrb_destroy(&hrb);
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_aws_canonical_request */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_bytes_to_hex
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of  `H5FD_s3comms_bytes_to_hex()`.
+ *
+ * Return:
+ *
+ *     Success:  0
+ *     Failure: -1
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-14
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_bytes_to_hex(void)
+{
+    /*************************
+     * test-local structures *
+     *************************/
+
+    struct testcase {
+        const char          exp[17]; /* in size * 2 + 1 for null terminator */
+        const unsigned char in[8];
+        size_t              size;
+        hbool_t             lower;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {   "52F3000C9A",
+            {82,243,0,12,154},
+            5,
+            FALSE,
+        },
+        {   "009a0cf3005200", /* lowercase alphas */
+            {0,154,12,243,0,82,0},
+            7,
+            TRUE,
+        },
+        {   "",
+            {17,63,26,56},
+            0,
+            FALSE, /* irrelevant */
+        },
+    };
+    int  i       = 0;
+    int  n_cases = 3;
+    char out[17];
+    int  out_off = 0;
+
+
+
+    TESTING("bytes-to-hex");
+
+    for (i = 0; i < n_cases; i++) {
+        for (out_off = 0; out_off < 17; out_off++) {
+            out[out_off] = 0;
+        }
+
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_bytes_to_hex(out,
+                                            cases[i].in,
+                                            cases[i].size,
+                                            cases[i].lower),
+                  NULL )
+
+        JSVERIFY_STR(cases[i].exp, out, NULL)
+    }
+
+    /* dest cannot be null
+     */
+    JSVERIFY( FAIL,
+              H5FD_s3comms_bytes_to_hex(
+                      NULL,
+                      (const unsigned char *)"nada",
+                      5,
+                      FALSE),
+               "destination cannot be null" )
+
+    PASSED();
+    return 0;
+
+error:
+    return -1;
+
+} /* test_bytes_to_hex */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_hrb_init_request()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_hrb_init_request()`
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-20
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_hrb_init_request(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+    /*********************
+     * test-local macros *
+     *********************/
+
+    /*************************
+     * test-local structures *
+     *************************/
+
+    struct testcase {
+        const char  msg[64];
+        const char *verb;
+        const char *resource;
+        const char *exp_res;
+        const char *version;
+        hbool_t     ret_null;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {   "get HTTP request just as we provided",
+            "GET",
+            "/path/to/some/file",
+            "/path/to/some/file",
+            "HTTP/1.1",
+            FALSE,
+        },
+        {   "null verb substitues to GET",
+            NULL,
+            "/MYPATH/MYFILE.tiff",
+            "/MYPATH/MYFILE.tiff",
+            "HTTP/1.1",
+            FALSE,
+        },
+        {   "demonstrate non-GET verb",
+            "HEAD",
+            "/MYPATH/MYFILE.tiff",
+            "/MYPATH/MYFILE.tiff",
+            "HTTP/1.1",
+            FALSE,
+        },
+        {   "slash prepented to resource path, if necessary",
+            NULL,
+            "MYPATH/MYFILE.tiff",
+            "/MYPATH/MYFILE.tiff",
+            NULL,
+            FALSE,
+        },
+        {   "null resource path causes problem",
+            "GET",
+            NULL,
+            NULL,
+            NULL,
+            TRUE,
+        },
+    };
+    struct testcase *C      = NULL;
+    unsigned int     i      = 0;
+    unsigned int     ncases = 5;
+    hrb_t           *req    = NULL;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("hrb_init_request");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (i = 0; i < ncases; i++) {
+        C = &cases[i];
+        req = H5FD_s3comms_hrb_init_request(C->verb,
+                                            C->resource,
+                                            C->version);
+        if (cases[i].ret_null == TRUE) {
+            FAIL_IF( req != NULL );
+        } else {
+            FAIL_IF( req == NULL );
+            JSVERIFY( S3COMMS_HRB_MAGIC, req->magic, NULL )
+            if (C->verb == NULL) {
+                JSVERIFY_STR( "GET", req->verb, NULL )
+            } else {
+                JSVERIFY_STR( req->verb, C->verb, NULL )
+            }
+            JSVERIFY_STR( "HTTP/1.1",  req->version,  NULL )
+            JSVERIFY_STR( C->exp_res,  req->resource, NULL )
+            FAIL_IF( req->first_header != NULL );
+            FAIL_IF( req->body         != NULL );
+            JSVERIFY( 0, req->body_len, NULL )
+            JSVERIFY( SUCCEED, H5FD_s3comms_hrb_destroy(&req),
+                      "unable to destroy hrb_t" )
+            FAIL_IF( NULL != req ); /* should annull pointer as well as free */
+        }
+
+    } /* for each testcase */
+
+    PASSED();
+    return 0;
+
+error:
+    (void)H5FD_s3comms_hrb_destroy(&req);
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_hrb_init_request */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_hrb_node_set()
+ *
+ * Purpose:
+ *
+ *     Test operations on hrb_node_t structure
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-22
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_hrb_node_set(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+    /*************************
+     * test-local structures *
+     *************************/
+
+    /* bundle of name/value representing an hrb_node_t
+     */
+    typedef struct node_mock_t {
+        const char *name;
+        const char *value;
+    } node_mock_t;
+
+    /* bundle for a testcase
+     *
+     * `message`
+     *     purpose of the testcase
+     *
+     * `delta`
+     *     container for name and value strings to pass into node-set function
+     *     to to modify the list.
+     *
+     * `returned`
+     *     expected return value of node-set function
+     *
+     * `given`
+     * `expected`
+     *     string arrays representing the state of the list before and after
+     *     modification. The number of strings must be even, with each name
+     *     paired to a value. `NULL` terminates the list, with `{NULL}`
+     *     representing the empty list.
+     */
+    typedef struct testcase {
+        const char  *message;
+        node_mock_t  delta;
+        herr_t       returned;
+        const char  *given[11]; /* name/value pairs in array; NULL sentinel */
+        const char  *expected[11];
+    } testcase;
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    testcase cases[] = {
+        {   "cannot remove node from null list",
+            { "Host", NULL },
+            FAIL,
+            {NULL},
+            {NULL},
+        },
+        {   "cannot create list with NULL field name",
+            { NULL, "somevalue" },
+            FAIL,
+            {NULL},
+            {NULL},
+        },
+        {   "create a new list",
+            { "Host", "somevalue" },
+            SUCCEED,
+            {NULL},
+            {   "Host", "somevalue",
+                NULL,
+            },
+        },
+        {   "insert new node at head list",
+            { "Host", "somevalue" },
+            SUCCEED,
+            {   "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Host", "somevalue",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+        },
+        {   "append new node at list end",
+            { "x-amz-date", "somevalue" },
+            SUCCEED,
+            {   "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Range", "bytes=20-40",
+                "x-amz-date", "somevalue",
+                NULL,
+            },
+        },
+        {   "insert new node inside list",
+            { "Intermediary", "somevalue" },
+            SUCCEED,
+            {   "Host", "somehost" ,
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Host", "somehost",
+                "Intermediary", "somevalue",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+        },
+        {   "modify node",
+            { "Range", "bytes=40-80" },
+            SUCCEED,
+            {   "Host", "somehost",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Host", "somehost",
+                "Range", "bytes=40-80",
+                NULL,
+            },
+        },
+        {   "modify node with new case",
+            { "RANGE", "bytes=40-80" },
+            SUCCEED,
+            {   "Host", "somehost",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Host", "somehost",
+                "RANGE", "bytes=40-80",
+                NULL,
+            },
+        },
+        {   "cannot add node with no name",
+            { NULL, "bytes=40-80" },
+            FAIL,
+            {   "Host", "somehost",
+                NULL,
+            },
+            {   "Host", "somehost",
+                NULL,
+            },
+        },
+        {   "add node with 'empty' name",
+            { "", "bytes=40-80" },
+            SUCCEED,
+            {   "Host", "somehost",
+                NULL,
+            },
+            {   "", "bytes=40-80",
+                "Host", "somehost",
+                NULL,
+            },
+        },
+        {   "remove node from end of list",
+            { "Host", NULL },
+            SUCCEED,
+            {   "Date", "Thr, 25 Jan 2018",
+                "Host", "somehost",
+                NULL,
+            },
+            {   "Date", "Thr, 25 Jan 2018",
+                NULL,
+            },
+        },
+        {   "remove node from middle of list",
+            { "Host", NULL },
+            SUCCEED,
+            {   "Date", "Thr, 25 Jan 2018",
+                "Host", "somehost",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Date", "Thr, 25 Jan 2018",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+        },
+        {   "remove node from start of list",
+            { "Date", NULL },
+            SUCCEED,
+            {   "Date", "Thr, 25 Jan 2018",
+                "Host", "somehost",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Host", "somehost",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+        },
+        {   "remove only node in list",
+            { "Date", NULL },
+            SUCCEED,
+            {   "Date", "Thr, 25 Jan 2018",
+                NULL,
+            },
+            {   NULL,
+            },
+        },
+        {   "attempt to remove absent node fails",
+            { "Host", NULL },
+            FAIL,
+            {   "Date", "Thr, 25 Jan 2018",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Date", "Thr, 25 Jan 2018",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+        },
+        {   "removal is case-insensitive",
+            { "hOsT", NULL },
+            SUCCEED,
+            {   "Date", "Thr, 25 Jan 2018",
+                "Host", "somehost",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+            {   "Date", "Thr, 25 Jan 2018",
+                "Range", "bytes=20-40",
+                NULL,
+            },
+        },
+    };
+    unsigned testcases_count = 16;
+    unsigned test_i = 0;
+
+    hrb_node_t *list = NULL;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("test_hrb_node_t");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (test_i = 0; test_i < testcases_count; test_i++) {
+        const hrb_node_t  *node = NULL;
+        const testcase    *test = &(cases[test_i]);
+        unsigned mock_i = 0;
+
+        /*********
+         * SETUP *
+         *********/
+
+        for (mock_i = 0; test->given[mock_i] != NULL; mock_i += 2) {
+            const char *name = test->given[mock_i];
+            const char *valu = test->given[mock_i+1];
+
+            FAIL_IF( SUCCEED !=
+                     H5FD_s3comms_hrb_node_set(&list, name, valu) )
+        }
+        /********
+         * TEST *
+         ********/
+
+        /* perform modification on list
+         */
+        JSVERIFY( test->returned,
+                  H5FD_s3comms_hrb_node_set(&list,
+                                            test->delta.name,
+                                            test->delta.value),
+                  test->message )
+
+
+        /* verify resulting list
+         */
+        node = list;
+        mock_i = 0;
+        while (test->expected[mock_i] != NULL && node != NULL) {
+            const char *name = test->expected[mock_i];
+            const char *valu = test->expected[mock_i+1];
+
+            JSVERIFY_STR( name, node->name, NULL )
+            JSVERIFY_STR( valu, node->value, NULL )
+
+            mock_i += 2;
+            node = node->next;
+        }
+        FAIL_IF( test->expected[mock_i] != NULL )
+        FAIL_IF( node != NULL )
+
+        /************
+         * TEARDOWN *
+         ************/
+
+        while (list != NULL) {
+            FAIL_IF( SUCCEED !=
+                     H5FD_s3comms_hrb_node_set(&list, list->name, NULL) )
+        }
+    }
+
+    PASSED();
+    return 0;
+
+error:
+    while (list != NULL)
+        (void)H5FD_s3comms_hrb_node_set(&list, list->name, NULL);
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_hrb_node_t */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_HMAC_SHA256()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_HMAC_SHA256()`
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-19
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_HMAC_SHA256(void)
+{
+
+    /*************************
+     * test-local structures *
+     *************************/
+
+#ifdef H5_HAVE_ROS3_VFD
+    struct testcase {
+        herr_t               ret; /* SUCCEED/FAIL expected from call */
+        const unsigned char  key[SHA256_DIGEST_LENGTH];
+        size_t               key_len;
+        const char          *msg;
+        size_t               msg_len;
+        const char          *exp; /* not used if ret == FAIL */
+        size_t               dest_size; /* if 0, `dest` is not malloc'd */
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {   SUCCEED,
+            {   0xdb, 0xb8, 0x93, 0xac, 0xc0, 0x10, 0x96, 0x49,
+                0x18, 0xf1, 0xfd, 0x43, 0x3a, 0xdd, 0x87, 0xc7,
+                0x0e, 0x8b, 0x0d, 0xb6, 0xbe, 0x30, 0xc1, 0xfb,
+                0xea, 0xfe, 0xfa, 0x5e, 0xc6, 0xba, 0x83, 0x78,
+            },
+            SHA256_DIGEST_LENGTH,
+            "AWS4-HMAC-SHA256\n20130524T000000Z\n20130524/us-east-1/s3/aws4_request\n7344ae5b7ee6c3e7e6b0fe0640412a37625d1fbfff95c48bbb2dc43964946972",
+            HDstrlen("AWS4-HMAC-SHA256\n20130524T000000Z\n20130524/us-east-1/s3/aws4_request\n7344ae5b7ee6c3e7e6b0fe0640412a37625d1fbfff95c48bbb2dc43964946972"),
+            "f0e8bdb87c964420e857bd35b5d6ed310bd44f0170aba48dd91039c6036bdb41",
+            SHA256_DIGEST_LENGTH * 2 + 1, /* +1 for null terminator */
+        },
+        {   SUCCEED,
+            {'J','e','f','e'},
+            4,
+            "what do ya want for nothing?",
+            28,
+            "5bdcc146bf60754e6a042426089575c75a003f089d2739839dec58b964ec3843",
+            SHA256_DIGEST_LENGTH * 2 + 1,
+        },
+        {    FAIL,
+             "DOESN'T MATTER",
+             14,
+             "ALSO IRRELEVANT",
+             15,
+             NULL,
+             0, /* dest -> null, resulting in immediate error */
+        },
+    };
+    char *dest    = NULL;
+    int   i       = 0;
+    int   n_cases = 3;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("HMAC_SHA256");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (i = 0; i < n_cases; i++) {
+        if (cases[i].dest_size == 0) {
+           dest = NULL;
+        } else {
+           dest = (char *)HDmalloc(sizeof(char) * cases[i].dest_size);
+           HDassert(dest != NULL);
+        }
+
+        JSVERIFY( cases[i].ret,
+                  H5FD_s3comms_HMAC_SHA256(
+                          cases[i].key,
+                          cases[i].key_len,
+                          cases[i].msg,
+                          cases[i].msg_len,
+                          dest),
+                  cases[i].msg );
+        if (cases[i].ret == SUCCEED) {
+#ifdef VERBOSE
+            if (0 !=
+                strncmp(cases[i].exp,
+                        dest,
+                        HDstrlen(cases[i].exp)))
+            {
+                /* print out how wrong things are, and then fail
+                 */
+                dest = (char *)realloc(dest, cases[i].dest_size + 1);
+                HDassert(dest != NULL);
+                dest[cases[i].dest_size] = 0;
+                HDfprintf(stdout,
+                          "ERROR:\n!!! \"%s\"\n != \"%s\"\n",
+                          cases[i].exp,
+                          dest);
+                TEST_ERROR;
+            }
+#else
+            /* simple pass/fail test
+             */
+            JSVERIFY( 0,
+                      strncmp(cases[i].exp, dest, HDstrlen(cases[i].exp)),
+                      NULL);
+#endif
+        }
+        free(dest);
+    }
+
+    PASSED();
+    return 0;
+
+error:
+    free(dest);
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_HMAC_SHA256 */
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Function: test_nlowercase()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_nlowercase()`
+ *
+ * Programmer: Jacob Smith
+ *             2017-19-18
+ *
+ *----------------------------------------------------------------------------
+ */
+static herr_t
+test_nlowercase(void)
+{
+    /*************************
+     * test-local structures *
+     *************************/
+
+#ifdef H5_HAVE_ROS3_VFD
+    struct testcase {
+        const char *in;
+        size_t      len;
+        const char *exp;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    /* any character after in exp on or after exp[len] is undefined.
+     * in this test, kept as the null character for simplicity.
+     */
+    struct testcase cases[] = {
+        {   "HALlEluJAh",
+            6,
+            "hallel",
+        },
+        {   "all\0 lower",
+            10,
+            "all\0 lower",
+        },
+        {   "to meeeeeee",
+            0,
+            "",
+        },
+    };
+    char *dest    = NULL;
+    int   i       = 0;
+    int   n_cases = 3;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("nlowercase");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (i = 0; i < n_cases; i++) {
+        dest = (char *)HDmalloc(sizeof(char) * 16);
+
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_nlowercase(dest,
+                                          cases[i].in,
+                                          cases[i].len),
+                  cases[i].in )
+        if (cases[i].len > 0) {
+            JSVERIFY( 0, strncmp(dest, cases[i].exp, cases[i].len), NULL )
+        }
+        free(dest);
+    }
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_nlowercase(NULL,
+                                      cases[0].in,
+                                      cases[0].len),
+              "null distination should fail" )
+
+    PASSED();
+    return 0;
+
+error:
+    free(dest);
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_nlowercase */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_parse_url()
+ *
+ * Programmer: Jacob Smith
+ *             2017-11-??
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_parse_url(void)
+{
+    /*********************
+     * test-local macros *
+     *********************/
+
+    /*************************
+     * test-local structures *
+     *************************/
+
+#ifdef H5_HAVE_ROS3_VFD
+    typedef struct {
+        const char *scheme;
+        const char *host;
+        const char *port;
+        const char *path;
+        const char *query;
+    } const_purl_t;
+
+    struct testcase {
+        const char   *url;
+        herr_t        exp_ret; /* expected return;              */
+                               /* if FAIL, `expected` is unused */
+        const_purl_t  expected;
+        const char   *msg;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    parsed_url_t   *purl    = NULL;
+    unsigned int    i       = 0;
+    unsigned int    ncases  = 15;
+    struct testcase cases[] = {
+        {   NULL,
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL },
+            "null url",
+        },
+        {   "",
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL },
+            "empty url",
+        },
+        {   "ftp://[1000:4000:0002:2010]",
+            SUCCEED,
+            {   "ftp",
+                "[1000:4000:0002:2010]",
+                NULL,
+                NULL,
+                NULL,
+            },
+            "IPv6 ftp and empty path (root)",
+        },
+        {   "ftp://[1000:4000:0002:2010]:2040",
+            SUCCEED,
+            {   "ftp",
+                "[1000:4000:0002:2010]",
+                "2040",
+                NULL,
+                NULL,
+            },
+            "root IPv6 ftp with port",
+        },
+        {   "http://some.domain.org:9000/path/to/resource.txt",
+            SUCCEED,
+            {   "http",
+                "some.domain.org",
+                "9000",
+                "path/to/resource.txt",
+                NULL,
+            },
+            "without query",
+        },
+        {   "https://domain.me:00/file.txt?some_params unchecked",
+            SUCCEED,
+            {   "https",
+                "domain.me",
+                "00",
+                "file.txt",
+                "some_params unchecked",
+            },
+            "with query",
+        },
+        {   "ftp://domain.com/",
+            SUCCEED,
+            {   "ftp",
+                "domain.com",
+                NULL,
+                NULL,
+                NULL,
+            },
+            "explicit root w/out port",
+        },
+        {   "ftp://domain.com:1234/",
+            SUCCEED,
+            {   "ftp",
+                "domain.com",
+                "1234",
+                NULL,
+                NULL,
+            },
+            "explicit root with port",
+        },
+        {   "ftp://domain.com:1234/file?",
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL, },
+            "empty query is invalid",
+        },
+        {   "ftp://:1234/file",
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL, },
+            "no host",
+        },
+        {   "h&r block",
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL, },
+            "no scheme (bad URL)",
+        },
+        {   "http://domain.com?a=b&d=b",
+            SUCCEED,
+            {   "http",
+                "domain.com",
+                NULL,
+                NULL,
+                "a=b&d=b",
+            },
+            "QUERY with implict PATH",
+        },
+        {   "http://[5]/path?a=b&d=b",
+            SUCCEED,
+            {   "http",
+                "[5]",
+                NULL,
+                "path",
+                "a=b&d=b",
+            },
+            "IPv6 extraction is really dumb",
+        },
+        {   "http://[1234:5678:0910:1112]:port/path",
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL, },
+            "non-decimal PORT (port)",
+        },
+        {   "http://mydomain.com:01a3/path",
+            FAIL,
+            { NULL, NULL, NULL, NULL, NULL, },
+            "non-decimal PORT (01a3)",
+        },
+    };
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("url-parsing functionality");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    /*********
+     * TESTS *
+     *********/
+
+    for (i = 0; i < ncases; i++) {
+        HDassert( purl == NULL );
+
+        JSVERIFY( cases[i].exp_ret,
+                  H5FD_s3comms_parse_url(cases[i].url, &purl),
+                  cases[i].msg )
+
+        if (cases[i].exp_ret == FAIL) {
+            /* on FAIL, `purl` should be untouched--remains NULL */
+            FAIL_UNLESS( purl == NULL )
+        } else {
+            /* on SUCCEED, `purl` should be set */
+            FAIL_IF( purl == NULL )
+
+            if (cases[i].expected.scheme != NULL) {
+                FAIL_IF( NULL == purl->scheme )
+                JSVERIFY_STR( cases[i].expected.scheme,
+                              purl->scheme,
+                              cases[i].msg )
+            } else {
+                FAIL_UNLESS( NULL == purl->scheme )
+            }
+
+            if (cases[i].expected.host != NULL) {
+                FAIL_IF( NULL == purl->host )
+                JSVERIFY_STR( cases[i].expected.host,
+                              purl->host,
+                              cases[i].msg )
+            } else {
+                FAIL_UNLESS( NULL == purl->host )
+            }
+
+            if (cases[i].expected.port != NULL) {
+                FAIL_IF( NULL == purl->port )
+                JSVERIFY_STR( cases[i].expected.port,
+                              purl->port,
+                              cases[i].msg )
+            } else {
+                FAIL_UNLESS( NULL == purl->port )
+            }
+
+            if (cases[i].expected.path != NULL) {
+                FAIL_IF( NULL == purl->path )
+                JSVERIFY_STR( cases[i].expected.path,
+                              purl->path,
+                              cases[i].msg )
+            } else {
+                FAIL_UNLESS( NULL == purl->path )
+            }
+
+            if (cases[i].expected.query != NULL) {
+                FAIL_IF( NULL == purl->query )
+                JSVERIFY_STR( cases[i].expected.query,
+                              purl->query,
+                              cases[i].msg )
+            } else {
+                FAIL_UNLESS( NULL == purl->query )
+            }
+        } /* if parse-url return SUCCEED/FAIL */
+
+        /* per-test cleanup
+         * well-behaved, even if `purl` is NULL
+         */
+        FAIL_IF( FAIL == H5FD_s3comms_free_purl(purl) )
+        purl = NULL;
+
+    } /* for each testcase */
+
+    PASSED();
+    return 0;
+
+error:
+    /***********
+     * cleanup *
+     ***********/
+    (void)H5FD_s3comms_free_purl(purl);
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_parse_url */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_percent_encode_char()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_percent_encode_char()`
+ *
+ * Return:
+ *
+ *     Success:  0
+ *     Failure: -1
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-14
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_percent_encode_char(void)
+{
+    /*************************
+     * test-local structures *
+     *************************/
+
+#ifdef H5_HAVE_ROS3_VFD
+    struct testcase {
+        const char  c;
+        const char *exp;
+        size_t      exp_len;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {'$', "%24", 3}, /* u+0024 dollar sign */
+        {' ', "%20", 3}, /* u+0020 space */
+        {'^', "%5E", 3}, /* u+0094 carat */
+        {'/', "%2F", 3}, /* u+002f solidus (forward slash) */
+        /* {??, "%C5%8C", 6},*/ /* u+014c Latin Capital Letter O with Macron */
+        /* Not included because it is multibyte "wide" character that poses  */
+        /* issues both in the underlying function and in being written in    */
+        /* this file.                                                        */
+        /* {'¢', "%C2%A2", 6}, */ /* u+00a2 cent sign */
+        /* above works, but complains about wide character overflow      */
+        /* Elide for now, until it is determined (a) unnecessary or      */
+        /* (b) requiring signature change to accommodate wide characters */
+        {'\0', "%00", 3}, /* u+0000 null */
+    };
+    char   dest[13];
+    size_t dest_len = 0;
+    int    i        = 0;
+    int    n_cases  = 5;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("percent encode characters");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (i = 0; i < n_cases; i++) {
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_percent_encode_char(
+                          dest,
+                          (const unsigned char)cases[i].c,
+                          &dest_len),
+                  NULL )
+        JSVERIFY(cases[i].exp_len, dest_len, NULL )
+        JSVERIFY(0, strncmp(dest, cases[i].exp, dest_len), NULL )
+        JSVERIFY_STR( cases[i].exp, dest, NULL )
+    }
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_percent_encode_char(
+                      NULL,
+                      (const unsigned char)'^',
+                      &dest_len),
+              NULL )
+
+    PASSED();
+    return 0;
+
+error:
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_percent_encode_char */
+
+
+/*---------------------------------------------------------------------------
+ * Function: test_s3r_open()
+ *
+ * Programmer: Jacob Smith 2018-01-24
+ *
+ * Changes: None
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_s3r_get_filesize(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    char url_raven[S3_TEST_MAX_URL_SIZE];
+    s3r_t *handle = NULL;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("s3r_get_filesize");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    /* setup -- compose url to target resource
+     */
+    if (FALSE == s3_test_bucket_defined) {
+        SKIPPED();
+        puts("    environment variable HDF5_ROS3_TEST_BUCKET_URL not defined");
+        fflush(stdout);
+        return 0;
+    }
+
+    FAIL_IF( S3_TEST_MAX_URL_SIZE <
+             HDsnprintf(url_raven,
+                      S3_TEST_MAX_URL_SIZE,
+                      "%s/%s",
+                      s3_test_bucket_url,
+                      S3_TEST_RESOURCE_TEXT_PUBLIC) );
+
+    JSVERIFY( 0, H5FD_s3comms_s3r_get_filesize(NULL),
+              "filesize of the null handle should be 0" )
+
+    handle = H5FD_s3comms_s3r_open(url_raven, NULL, NULL, NULL);
+    FAIL_IF( handle == NULL )
+
+    JSVERIFY( 6464, H5FD_s3comms_s3r_get_filesize(handle), NULL )
+
+
+    FAIL_IF( SUCCEED != H5FD_s3comms_s3r_close(handle) )
+
+    PASSED();
+    return 0;
+
+error:
+    if (handle != NULL)
+        (void)H5FD_s3comms_s3r_close(handle);
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_s3r_get_filesize */
+
+
+/*---------------------------------------------------------------------------
+ * Function: test_s3r_open()
+ *
+ * Programmer: Jacob Smith 2018-01-??
+ *
+ * Changes: None
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_s3r_open(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    char           url_missing[S3_TEST_MAX_URL_SIZE];
+    char           url_raven[S3_TEST_MAX_URL_SIZE];
+    char           url_raven_badport[S3_TEST_MAX_URL_SIZE];
+    char           url_shakespeare[S3_TEST_MAX_URL_SIZE];
+    unsigned char  signing_key[SHA256_DIGEST_LENGTH];
+    struct tm     *now          = NULL;
+    char           iso8601now[ISO8601_SIZE];
+    s3r_t         *handle       = NULL;
+    hbool_t        curl_ready   = FALSE;
+    parsed_url_t  *purl         = NULL;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("s3r_open");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    if (s3_test_credentials_loaded == 0) {
+        SKIPPED();
+        puts("    s3 credentials are not loaded");
+        fflush(stdout);
+        return 0;
+    }
+    if (FALSE == s3_test_bucket_defined) {
+        SKIPPED();
+        puts("    environment variable HDF5_ROS3_TEST_BUCKET_URL not defined");
+        fflush(stdout);
+        return 0;
+    }
+
+    /******************
+     * PRE-TEST SETUP *
+     ******************/
+
+    FAIL_IF( S3_TEST_MAX_URL_SIZE <
+             HDsnprintf(url_shakespeare,
+                      S3_TEST_MAX_URL_SIZE,
+                      "%s/%s",
+                      s3_test_bucket_url,
+                      S3_TEST_RESOURCE_TEXT_RESTRICTED) );
+
+    FAIL_IF( S3_TEST_MAX_URL_SIZE <
+             HDsnprintf(url_missing,
+                      S3_TEST_MAX_URL_SIZE,
+                      "%s/%s",
+                      s3_test_bucket_url,
+                      S3_TEST_RESOURCE_MISSING) );
+
+    FAIL_IF( S3_TEST_MAX_URL_SIZE <
+             HDsnprintf(url_raven,
+                      S3_TEST_MAX_URL_SIZE,
+                      "%s/%s",
+                      s3_test_bucket_url,
+                      S3_TEST_RESOURCE_TEXT_PUBLIC) );
+
+    /* Set given bucket url with invalid/inactive port number for badport.
+     * Note, this sort of micro-management of parsed_url_t is not advised
+     */
+    FAIL_IF( FAIL == H5FD_s3comms_parse_url(s3_test_bucket_url, &purl) )
+    if (purl->port == NULL) {
+        purl->port = (char *)H5MM_malloc(sizeof(char) * 5);
+        FAIL_IF( purl->port == NULL );
+        FAIL_IF( 5 < HDsnprintf(purl->port, 5, "9000") )
+    } else if (strcmp(purl->port, "9000") != 0) {
+        FAIL_IF( 5 < HDsnprintf(purl->port, 5, "9000") )
+    } else {
+        FAIL_IF( 5 < HDsnprintf(purl->port, 5, "1234") )
+    }
+    FAIL_IF( S3_TEST_MAX_URL_SIZE <
+             HDsnprintf(url_raven_badport,
+                      S3_TEST_MAX_URL_SIZE,
+                      "%s://%s:%s/%s",
+                      purl->scheme,
+                      purl->host,
+                      purl->port,
+                      S3_TEST_RESOURCE_TEXT_PUBLIC) );
+
+    curl_global_init(CURL_GLOBAL_DEFAULT);
+    curl_ready = TRUE;
+
+    now = gmnow();
+    FAIL_IF( now == NULL )
+    FAIL_IF( ISO8601NOW(iso8601now, now) != (ISO8601_SIZE - 1) );
+
+    /* It is desired to have means available to verify that signing_key
+     * was set successfully and to an expected value.
+     */
+    FAIL_IF( FAIL ==
+             H5FD_s3comms_signing_key(
+                     signing_key,
+                     (const char *)s3_test_aws_secret_access_key,
+                     (const char *)s3_test_aws_region,
+                     (const char *)iso8601now) );
+
+    /*************************
+     * OPEN NONEXISTENT FILE *
+     *************************/
+
+    /* attempt anonymously
+     */
+    handle = H5FD_s3comms_s3r_open(url_missing, NULL, NULL, NULL);
+    FAIL_IF( handle != NULL );
+
+    /* attempt with authentication
+     */
+    handle = H5FD_s3comms_s3r_open(
+             url_missing,
+             (const char *)s3_test_aws_region,
+             (const char *)s3_test_aws_access_key_id,
+             (const unsigned char *)signing_key);
+    FAIL_IF( handle != NULL );
+
+    /*************************
+     * INACTIVE PORT ON HOST *
+     *************************/
+
+#if S3_TEST_RUN_TIMEOUT
+printf("Opening on inactive port may hang for a minute; waiting for timeout\n");
+    handle = H5FD_s3comms_s3r_open(url_raven_badport, NULL, NULL, NULL);
+    FAIL_IF( handle != NULL );
+#endif
+
+    /*******************************
+     * INVALID AUTHENTICATION INFO *
+     *******************************/
+
+    /* anonymous access on restricted file
+     */
+    handle = H5FD_s3comms_s3r_open(url_shakespeare, NULL, NULL, NULL);
+    FAIL_IF( handle != NULL );
+
+    /* passed in a bad ID
+     */
+    handle = H5FD_s3comms_s3r_open(
+             url_shakespeare,
+             (const char *)s3_test_aws_region,
+             "I_MADE_UP_MY_ID",
+             (const unsigned char *)signing_key);
+    FAIL_IF( handle != NULL );
+
+    /* using an invalid signing key
+     */
+    handle = H5FD_s3comms_s3r_open(
+             url_shakespeare,
+             (const char *)s3_test_aws_region,
+             (const char *)s3_test_aws_access_key_id,
+             (const unsigned char *)EMPTY_SHA256);
+    FAIL_IF( handle != NULL );
+
+    /*******************************
+     * SUCCESSFUL OPEN (AND CLOSE) *
+     *******************************/
+
+    /* anonymous
+     */
+    handle = H5FD_s3comms_s3r_open(url_raven, NULL, NULL, NULL);
+    FAIL_IF( handle == NULL );
+    JSVERIFY( 6464, H5FD_s3comms_s3r_get_filesize(handle),
+              "did not get expected filesize" )
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_close(handle),
+              "unable to close file" )
+    handle = NULL;
+
+    /* using authentication on anonymously-accessible file?
+     */
+    handle = H5FD_s3comms_s3r_open(
+             url_raven,
+             (const char *)s3_test_aws_region,
+             (const char *)s3_test_aws_access_key_id,
+             (const unsigned char *)signing_key);
+    FAIL_IF( handle == NULL );
+    JSVERIFY( 6464, H5FD_s3comms_s3r_get_filesize(handle), NULL )
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_close(handle),
+              "unable to close file" )
+    handle = NULL;
+
+    /* authenticating
+     */
+    handle = H5FD_s3comms_s3r_open(
+                     url_shakespeare,
+                     (const char *)s3_test_aws_region,
+                     (const char *)s3_test_aws_access_key_id,
+                     (const unsigned char *)signing_key);
+    FAIL_IF( handle == NULL );
+    JSVERIFY( 5458199, H5FD_s3comms_s3r_get_filesize(handle), NULL )
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_close(handle),
+              "unable to close file" )
+    handle = NULL;
+
+
+
+    curl_global_cleanup();
+    curl_ready = FALSE;
+
+    FAIL_IF( FAIL == H5FD_s3comms_free_purl(purl) )
+    purl = NULL;
+
+    PASSED();
+    return 0;
+error:
+    /***********
+     * cleanup *
+     ***********/
+
+    if (handle != NULL)
+        H5FD_s3comms_s3r_close(handle);
+    if (purl != NULL)
+        H5FD_s3comms_free_purl(purl);
+    if (curl_ready == TRUE)
+        curl_global_cleanup();
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_s3r_open */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_s3r_read()
+ *
+ * Purpose:
+ *
+ *     Specify and demonstrate the use and life cycle of an S3 Request handle
+ *     `s3r_t`, through its related functions.
+ *
+ *     H5FD_s3comms_s3r_open
+ *     H5FD_s3comms_s3r_getsize << called by open() _only_
+ *     H5FD_s3comms_s3r_read    << called by getsize(), multiple times working
+ *     H5FD_s3comms_s3r_close
+ *
+ *     Shows most basic curl interation.
+ *
+ * Programmer: Jacob Smith
+ *             2017-10-06
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_s3r_read(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+
+#define S3COMMS_TEST_BUFFER_SIZE 256
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    char           url_raven[S3_TEST_MAX_URL_SIZE];
+    char           buffer[S3COMMS_TEST_BUFFER_SIZE];
+    s3r_t         *handle     = NULL;
+    hbool_t        curl_ready = FALSE;
+    unsigned int   i          = 0;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("test_s3r_read");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    /*
+     * initial setup
+     */
+    if (FALSE == s3_test_bucket_defined) {
+        SKIPPED();
+        puts("    environment variable HDF5_ROS3_TEST_BUCKET_URL not defined");
+        fflush(stdout);
+        return 0;
+    }
+
+    curl_global_init(CURL_GLOBAL_DEFAULT);
+    curl_ready = TRUE;
+    FAIL_IF( S3_TEST_MAX_URL_SIZE <
+             HDsnprintf(url_raven,
+                      S3_TEST_MAX_URL_SIZE,
+                      "%s/%s",
+                      s3_test_bucket_url,
+                      S3_TEST_RESOURCE_TEXT_PUBLIC) );
+
+    for (i = 0; i < S3COMMS_TEST_BUFFER_SIZE; i++)
+        buffer[i] = '\0';
+
+    /* open file
+     */
+    handle = H5FD_s3comms_s3r_open(url_raven, NULL, NULL, NULL);
+    FAIL_IF( handle == NULL )
+    JSVERIFY( 6464, H5FD_s3comms_s3r_get_filesize(handle), NULL )
+
+    for (i = 0; i < S3COMMS_TEST_BUFFER_SIZE; i++)
+        buffer[i] = '\0';
+
+    /**********************
+     * read start of file *
+     **********************/
+
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)0,
+                      (size_t)118,
+                      buffer),
+              NULL )
+    JSVERIFY_STR (
+            "Once upon a midnight dreary, while I pondered, weak and weary,\n" \
+            "Over many a quaint and curious volume of forgotten lore",
+            buffer,
+            NULL )
+
+    for (i = 0; i < S3COMMS_TEST_BUFFER_SIZE; i++)
+        buffer[i] = '\0';
+
+    /************************
+     * read arbitrary range *
+     ************************/
+
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)2540,
+                      (size_t)54,
+                      buffer),
+              NULL )
+    JSVERIFY_STR( "the grave and stern decorum of the countenance it wore",
+                  buffer,
+                  NULL )
+
+    for (i = 0; i < S3COMMS_TEST_BUFFER_SIZE; i++)
+        buffer[i] = '\0';
+
+    /**********************
+     * read one character *
+     **********************/
+
+    JSVERIFY(SUCCEED,
+             H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)2540,
+                      (size_t)1,
+                      buffer),
+              NULL )
+    JSVERIFY_STR( "t", buffer, NULL )
+
+
+    for (i = 0; i < S3COMMS_TEST_BUFFER_SIZE; i++)
+        buffer[i] = '\0';
+
+    /***************
+     * read to EoF *
+     ***************/
+
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)6370,
+                      (size_t)0,
+                      buffer),
+              NULL )
+    JSVERIFY( 0,
+              strncmp(buffer,
+                      "And my soul from out that shadow that lies floating on the floor\nShall be lifted—nevermore!\n",
+                      94),
+              buffer )
+
+    for (i = 0; i < S3COMMS_TEST_BUFFER_SIZE; i++)
+        buffer[i] = '\0';
+
+    /*****************
+     * read past eof *
+     *****************/
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)6400,
+                      (size_t)100, /* 6400+100 > 6464 */
+                      buffer),
+              NULL )
+     JSVERIFY( 0, strcmp("", buffer), NULL )
+
+    /************************
+     * read starts past eof *
+     ************************/
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)1200699, /* 1200699 > 6464 */
+                      (size_t)100,
+                      buffer),
+              NULL )
+     JSVERIFY( 0, strcmp("", buffer), NULL )
+
+    /**********************
+     * read starts on eof *
+     **********************/
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_s3r_read(
+                      handle,
+                      (haddr_t)6464,
+                      (size_t)0,
+                      buffer),
+              NULL )
+     JSVERIFY( 0, strcmp("", buffer), NULL )
+
+    /*************
+     * TEAR DOWN *
+     *************/
+
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_s3r_close(handle),
+              "unable to close file" )
+    handle = NULL;
+
+    curl_global_cleanup();
+    curl_ready = FALSE;
+
+    PASSED();
+    return 0;
+
+error:
+    /***********
+     * cleanup *
+     ***********/
+
+    if (handle != NULL)
+        H5FD_s3comms_s3r_close(handle);
+
+    if (curl_ready == TRUE)
+        curl_global_cleanup();
+
+    return -1;
+
+#undef S3COMMS_TEST_BUFFER_SIZE
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_s3r_read */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_signing_key()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_signing_key()`
+ *
+ *     More test cases would be a very good idea.
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-18
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_signing_key(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+    /*************************
+     * test-local structures *
+     *************************/
+
+    struct testcase {
+        const char    *region;
+        const char    *secret_key;
+        const char    *when;
+        unsigned char  exp[SHA256_DIGEST_LENGTH];
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {   "us-east-1",
+            "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY",
+            "20130524T000000Z",
+            {   0xdb, 0xb8, 0x93, 0xac, 0xc0, 0x10, 0x96, 0x49,
+                0x18, 0xf1, 0xfd, 0x43, 0x3a, 0xdd, 0x87, 0xc7,
+                0x0e, 0x8b, 0x0d, 0xb6, 0xbe, 0x30, 0xc1, 0xfb,
+                0xea, 0xfe, 0xfa, 0x5e, 0xc6, 0xba, 0x83, 0x78,
+            },
+        },
+    };
+    int            i      = 0;
+    unsigned char *key    = NULL;
+    int            ncases = 1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("signing_key");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    for (i = 0; i < ncases; i++) {
+        key = (unsigned char *)HDmalloc(sizeof(unsigned char) * \
+                                      SHA256_DIGEST_LENGTH);
+    HDassert(key != NULL);
+
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_signing_key(
+                          key,
+                          cases[i].secret_key,
+                          cases[i].region,
+                          cases[i].when),
+                  NULL )
+
+        JSVERIFY( 0,
+                  strncmp((const char *)cases[i].exp,
+                          (const char *)key,
+                          SHA256_DIGEST_LENGTH),
+                   cases[i].exp )
+
+        free(key);
+        key = NULL;
+    }
+
+
+    /***************
+     * ERROR CASES *
+     ***************/
+
+    key = (unsigned char *)HDmalloc(sizeof(unsigned char) * \
+                                  SHA256_DIGEST_LENGTH);
+    HDassert(key != NULL);
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_signing_key(
+                      NULL,
+                      cases[0].secret_key,
+                      cases[0].region,
+                      cases[0].when),
+              "destination cannot be NULL" )
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_signing_key(
+                      key,
+                      NULL,
+                      cases[0].region,
+                      cases[0].when),
+              "secret key cannot be NULL" )
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_signing_key(
+                      key,
+                      cases[0].secret_key,
+                      NULL,
+                      cases[0].when),
+              "aws region cannot be NULL" )
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_signing_key(
+                      key,
+                      cases[0].secret_key,
+                      cases[0].region,
+                      NULL),
+              "time string cannot be NULL" )
+
+    free(key);
+    key = NULL;
+
+    PASSED();
+    return 0;
+
+error:
+    if (key != NULL) {
+        free(key);
+    }
+
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_signing_key */
+
+
+/*---------------------------------------------------------------------------
+ *
+ * Function: test_tostringtosign()
+ *
+ * Purpose:
+ *
+ *     Verify that we can get the "string to sign" from a Canonical Request and
+ *     related information.
+ *
+ *     Demonstrate failure cases.
+ *
+ * Return:
+ *
+ *     Success:  0
+ *     Failure: -1
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-13
+ *
+ *---------------------------------------------------------------------------
+ */
+static herr_t
+test_tostringtosign(void)
+{
+#ifdef H5_HAVE_ROS3_VFD
+    /************************
+     * test-local variables *
+     ************************/
+
+    const char canonreq[]   = "GET\n/test.txt\n\nhost:examplebucket.s3.amazonaws.com\nrange:bytes=0-9\nx-amz-content-sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855\nx-amz-date:20130524T000000Z\n\nhost;range;x-amz-content-sha256;x-amz-date\ne3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855";
+    const char iso8601now[] = "20130524T000000Z";
+    const char region[]     = "us-east-1";
+    char s2s[512];
+#endif /* H5_HAVE_ROS3_VFD */
+
+    TESTING("s3comms tostringtosign");
+
+#ifndef H5_HAVE_ROS3_VFD
+    SKIPPED();
+    puts("    ROS3 VFD is not enabled");
+    fflush(stdout);
+    return 0;
+#else
+    JSVERIFY( SUCCEED,
+              H5FD_s3comms_tostringtosign(s2s, canonreq, iso8601now, region),
+              "unable to create string to sign" )
+
+    JSVERIFY_STR( "AWS4-HMAC-SHA256\n20130524T000000Z\n20130524/us-east-1/s3/aws4_request\n7344ae5b7ee6c3e7e6b0fe0640412a37625d1fbfff95c48bbb2dc43964946972",
+                 s2s, NULL )
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_tostringtosign(s2s, NULL, iso8601now, region),
+              "canonical request string cannot be NULL" )
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_tostringtosign(s2s, canonreq, NULL, region),
+              "time string cannot be NULL" )
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_tostringtosign(s2s, canonreq, iso8601now, NULL),
+              "aws region cannot be NULL" )
+
+    PASSED();
+    return 0;
+
+error :
+    return -1;
+#endif /* H5_HAVE_ROS3_VFD */
+
+} /* test_tostringtosign */
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Function: test_trim()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_trim()`.
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-14
+ *
+ *----------------------------------------------------------------------------
+ */
+static herr_t
+test_trim(void)
+{
+    /*************************
+     * test-local structures *
+     *************************/
+
+    struct testcase {
+        const char *in;
+        size_t      in_len;
+        const char *exp;
+        size_t      exp_len;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {   "block string",
+            12,
+            "block string",
+            12,
+        },
+        {   " \n\r  \t",
+            6,
+            "",
+            0,
+        },
+        {   " \twhite b4",
+            10,
+            "white b4",
+            8,
+        },
+        {   "white after\r\n  ",
+            15,
+            "white after",
+            11,
+        },
+        {   " on\nends\t",
+            9,
+            "on\nends",
+            7,
+        },
+    };
+    char    dest[32];
+    size_t  dest_len = 0;
+    int     i        = 0;
+    int     n_cases  = 5;
+    char   *str      = NULL;
+
+
+
+    TESTING("s3comms trim");
+
+    for (i = 0; i < n_cases; i++) {
+        HDassert(str == NULL);
+        str = (char *)HDmalloc(sizeof(char) * cases[i].in_len);
+        HDassert(str != NULL);
+        HDstrncpy(str, cases[i].in, cases[i].in_len);
+
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_trim(dest, str, cases[i].in_len, &dest_len),
+                  NULL )
+        JSVERIFY( cases[i].exp_len, dest_len, cases[i].in )
+        if (dest_len > 0) {
+           JSVERIFY( 0, strncmp(cases[i].exp, dest, dest_len),
+                     cases[i].exp )
+        }
+        free(str);
+        str = NULL;
+    }
+
+    JSVERIFY( SUCCEED, H5FD_s3comms_trim(dest, NULL, 3, &dest_len),
+              "should not fail when trimming a null string" );
+    JSVERIFY( 0, dest_len, "trimming NULL string writes 0 characters" )
+
+    HDassert(str == NULL);
+    str = (char *)HDmalloc(sizeof(char *) * 11);
+    HDassert(str != NULL);
+    memcpy(str, "some text ", 11); /* string with null terminator */
+    JSVERIFY( FAIL, H5FD_s3comms_trim(NULL, str, 10, &dest_len),
+              "destination for trim cannot be NULL" );
+    free(str);
+    str = NULL;
+
+    PASSED();
+    return 0;
+
+error:
+    if (str != NULL)
+        free(str);
+    return -1;
+
+} /* test_trim */
+
+
+/*----------------------------------------------------------------------------
+ *
+ * Function: test_uriencode()
+ *
+ * Purpose:
+ *
+ *     Define and verify behavior of `H5FD_s3comms_uriencode()`.
+ *
+ * Programmer: Jacob Smith
+ *             2017-09-14
+ *
+ *----------------------------------------------------------------------------
+ */
+static herr_t
+test_uriencode(void)
+{
+    /*************************
+     * test-local structures *
+     *************************/
+
+    struct testcase {
+        const char *str;
+        size_t      s_len;
+        hbool_t     encode_slash;
+        const char *expected;
+    };
+
+    /************************
+     * test-local variables *
+     ************************/
+
+    struct testcase cases[] = {
+        {   "/path/to/resource.jpg",
+            21,
+            FALSE,
+            "/path/to/resource.jpg",
+        },
+        {   "/path/to/resource.jpg",
+            21,
+            TRUE,
+            "%2Fpath%2Fto%2Fresource.jpg",
+        },
+        {   "string got_spaa  ces",
+            20,
+            TRUE,
+            "string%20got_spaa%20%20ces",
+        },
+        {   "sp ac~es/and-sl ash.encoded",
+            27,
+            TRUE,
+            "sp%20ac~es%2Fand-sl%20ash.encoded",
+        },
+        {   "sp ac~es/and-sl ash.unencoded",
+            29,
+            FALSE,
+            "sp%20ac~es/and-sl%20ash.unencoded",
+        },
+        {   "/path/to/resource.txt",
+            0,
+            FALSE,
+            "",
+
+        }
+    };
+    char   *dest         = NULL;
+    size_t  dest_written = 0;
+    int     i            = 0;
+    int     ncases       = 6;
+    size_t  str_len      = 0;
+
+
+
+    TESTING("s3comms uriencode")
+
+    for (i = 0; i < ncases; i++) {
+        str_len = cases[i].s_len;
+        dest = (char *)HDmalloc(sizeof(char) * str_len * 3 + 1);
+        FAIL_IF( dest == NULL )
+
+        JSVERIFY( SUCCEED,
+                  H5FD_s3comms_uriencode(
+                          dest,
+                          cases[i].str,
+                          str_len,
+                          cases[i].encode_slash,
+                          &dest_written),
+                  NULL );
+        JSVERIFY( HDstrlen(cases[i].expected),
+                  dest_written,
+                  NULL )
+        JSVERIFY( 0,
+                  strncmp(dest, cases[i].expected, dest_written),
+                  cases[i].expected );
+
+        free(dest);
+        dest = NULL;
+    }
+
+    /***************
+     * ERROR CASES *
+     ***************/
+
+    dest = (char *)HDmalloc(sizeof(char) * 15);
+    HDassert(dest != NULL);
+
+    JSVERIFY( FAIL,
+              H5FD_s3comms_uriencode(NULL, "word$", 5, false, &dest_written),
+              "destination cannot be NULL" );
+    JSVERIFY( FAIL,
+              H5FD_s3comms_uriencode(dest, NULL, 5, false, &dest_written),
+              "source string cannot be NULL" );
+
+    free(dest);
+    dest = NULL;
+
+    PASSED();
+    return 0;
+
+error:
+    if (dest != NULL) {
+        free(dest);
+    }
+    return -1;
+
+} /* test_uriencode */
+
+
+
+
+/*-------------------------------------------------------------------------
+ * Function: main()
+ *
+ * Purpose:
+ *
+ *     Run unit tests for S3 Communications (s3comms).
+ *
+ * Return:
+ *
+ *     Success: 0
+ *     Failure: 1
+ *
+ * Programmer:  Jacob Smith
+ *              2017-10-12
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+main(void)
+{
+    int nerrors = 0;
+#ifdef H5_HAVE_ROS3_VFD
+    const char *bucket_url_env = NULL;
+#endif /* H5_HAVE_ROS3_VFD */
+
+    h5_reset();
+
+    HDprintf("Testing S3Communications functionality.\n");
+
+#ifdef H5_HAVE_ROS3_VFD
+
+    /* "clear" profile data strings */
+    s3_test_aws_access_key_id[0]     = '\0';
+    s3_test_aws_secret_access_key[0] = '\0';
+    s3_test_aws_region[0]            = '\0';
+    s3_test_bucket_url[0]            = '\0';
+
+/* TODO: unit/regression test for H5FD_s3comms_load_aws_profile()
+ * requires a few test files and/or manipulation of default path
+ */
+    /* attempt to load test credentials
+     * if unable, certain tests will be skipped
+     */
+    if (SUCCEED == H5FD_s3comms_load_aws_profile(
+            S3_TEST_PROFILE_NAME,
+            s3_test_aws_access_key_id,
+            s3_test_aws_secret_access_key,
+            s3_test_aws_region))
+    {
+        s3_test_credentials_loaded = 1;
+    }
+
+    bucket_url_env = HDgetenv("HDF5_ROS3_TEST_BUCKET_URL");
+    if (bucket_url_env == NULL || bucket_url_env[0] == '\0') {
+        HDprintf("WARNING: S3 bucket url is not defined in enviornment " \
+                 "variable 'HDF5_ROS3_TEST_BUCKET_URL'!\n");
+    } else {
+        HDstrncpy(s3_test_bucket_url, bucket_url_env, S3_TEST_MAX_URL_SIZE);
+        s3_test_bucket_defined = TRUE;
+    }
+
+#endif /* H5_HAVE_ROS3_VFD */
+
+    /* tests ordered rougly by dependence */
+    nerrors += test_macro_format_credential() < 0 ? 1 : 0;
+    nerrors += test_trim()                    < 0 ? 1 : 0;
+    nerrors += test_nlowercase()              < 0 ? 1 : 0;
+    nerrors += test_uriencode()               < 0 ? 1 : 0;
+    nerrors += test_percent_encode_char()     < 0 ? 1 : 0;
+    nerrors += test_bytes_to_hex()            < 0 ? 1 : 0;
+    nerrors += test_HMAC_SHA256()             < 0 ? 1 : 0;
+    nerrors += test_signing_key()             < 0 ? 1 : 0;
+    nerrors += test_hrb_node_set()            < 0 ? 1 : 0;
+    nerrors += test_hrb_init_request()        < 0 ? 1 : 0;
+    nerrors += test_parse_url()               < 0 ? 1 : 0;
+    nerrors += test_aws_canonical_request()   < 0 ? 1 : 0;
+    nerrors += test_tostringtosign()          < 0 ? 1 : 0;
+    nerrors += test_s3r_open()                < 0 ? 1 : 0;
+    nerrors += test_s3r_get_filesize()        < 0 ? 1 : 0;
+    nerrors += test_s3r_read()                < 0 ? 1 : 0;
+
+    if(nerrors) {
+        HDprintf("***** %d S3comms TEST%s FAILED! *****\n",
+                 nerrors,
+                 nerrors > 1 ? "S" : "");
+        return 1;
+    } /* end if */
+
+    HDprintf("All S3comms tests passed.\n");
+
+    return 0;
+} /* end main() */
+