Merge branch 'develop' into feature/coding_standardsfeature/coding_standards

1 files changed, 1272 insertions, 254 deletions

diff --git a/test/vol.c b/test/vol.c
index 5ff0af0..aba9311 100644
--- a/test/vol.c
+++ b/test/vol.c
@@ -5,7 +5,7 @@
  * This file is part of HDF5.  The full HDF5 copyright notice, including     *
  * terms governing use, modification, and redistribution, is contained in    *
  * the COPYING file, which can be found at the root of the source code       *
- * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * distribution tree, or in https://www.hdfgroup.org/licenses.               *
  * If you do not have access to either file, you may request a copy from     *
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
@@ -18,123 +18,557 @@
  *          other mechanisms.
  */
 
+/* Headers needed */
 #include "h5test.h"
+#include "H5Iprivate.h" /* IDs                                  */
+#define H5T_FRIEND      /* Suppress error about including H5Tpkg    */
+#include "H5Tpkg.h"     /* Datatypes                            */
+#define H5VL_FRIEND     /* Suppress error about including H5VLpkg    */
+#define H5VL_TESTING
+#include "H5VLpkg.h" /* Virtual Object Layer                 */
 
 /* Filename */
-const char *FILENAME[] = {
-    "native_vol_test",
-    NULL
+const char *FILENAME[] = {"native_vol_test", NULL};
+
+#define NATIVE_VOL_TEST_GROUP_NAME     "test_group"
+#define NATIVE_VOL_TEST_DATASET_NAME   "test_dataset"
+#define NATIVE_VOL_TEST_ATTRIBUTE_NAME "test_dataset"
+#define NATIVE_VOL_TEST_HARD_LINK_NAME "test_hard_link"
+#define NATIVE_VOL_TEST_SOFT_LINK_NAME "test_soft_link"
+#define NATIVE_VOL_TEST_MOVE_LINK_NAME "test_move_link"
+#define NATIVE_VOL_TEST_COPY_LINK_NAME "test_copy_link"
+#define NATIVE_VOL_TEST_DATATYPE_NAME  "test_datatype"
+
+#define N_ELEMENTS 10
+
+/* A VOL class struct to verify registering optional operations */
+static int    reg_opt_curr_op_val;
+static herr_t reg_opt_op_optional(void *obj, H5VL_optional_args_t *args, hid_t dxpl_id, void **req);
+static herr_t reg_opt_link_optional(void *obj, const H5VL_loc_params_t *loc_params,
+                                    H5VL_optional_args_t *args, hid_t dxpl_id, void **req);
+static herr_t reg_opt_datatype_get(void *obj, H5VL_datatype_get_args_t *args, hid_t dxpl_id, void **req);
+#define REG_OPT_VOL_NAME  "reg_opt"
+#define REG_OPT_VOL_VALUE ((H5VL_class_value_t)502)
+static const H5VL_class_t reg_opt_vol_g = {
+    H5VL_VERSION,      /* VOL class struct version */
+    REG_OPT_VOL_VALUE, /* value        */
+    REG_OPT_VOL_NAME,  /* name         */
+    0,                 /* version      */
+    0,                 /* capability flags */
+    NULL,              /* initialize   */
+    NULL,              /* terminate    */
+    {
+        /* info_cls */
+        (size_t)0, /* size    */
+        NULL,      /* copy    */
+        NULL,      /* compare */
+        NULL,      /* free    */
+        NULL,      /* to_str  */
+        NULL,      /* from_str */
+    },
+    {
+        /* wrap_cls */
+        NULL, /* get_object   */
+        NULL, /* get_wrap_ctx */
+        NULL, /* wrap_object  */
+        NULL, /* unwrap_object */
+        NULL, /* free_wrap_ctx */
+    },
+    {
+        /* attribute_cls */
+        NULL,                /* create       */
+        NULL,                /* open         */
+        NULL,                /* read         */
+        NULL,                /* write        */
+        NULL,                /* get          */
+        NULL,                /* specific     */
+        reg_opt_op_optional, /* optional     */
+        NULL                 /* close        */
+    },
+    {
+        /* dataset_cls */
+        NULL,                /* create       */
+        NULL,                /* open         */
+        NULL,                /* read         */
+        NULL,                /* write        */
+        NULL,                /* get          */
+        NULL,                /* specific     */
+        reg_opt_op_optional, /* optional     */
+        NULL                 /* close        */
+    },
+    {
+        /* datatype_cls */
+        NULL,                 /* commit       */
+        NULL,                 /* open         */
+        reg_opt_datatype_get, /* get          */
+        NULL,                 /* specific     */
+        reg_opt_op_optional,  /* optional     */
+        NULL                  /* close        */
+    },
+    {
+        /* file_cls */
+        NULL,                /* create       */
+        NULL,                /* open         */
+        NULL,                /* get          */
+        NULL,                /* specific     */
+        reg_opt_op_optional, /* optional     */
+        NULL                 /* close        */
+    },
+    {
+        /* group_cls */
+        NULL,                /* create       */
+        NULL,                /* open         */
+        NULL,                /* get          */
+        NULL,                /* specific     */
+        reg_opt_op_optional, /* optional     */
+        NULL                 /* close        */
+    },
+    {
+        /* link_cls */
+        NULL,                 /* create       */
+        NULL,                 /* copy         */
+        NULL,                 /* move         */
+        NULL,                 /* get          */
+        NULL,                 /* specific     */
+        reg_opt_link_optional /* optional     */
+    },
+    {
+        /* object_cls */
+        NULL,                 /* open         */
+        NULL,                 /* copy         */
+        NULL,                 /* get          */
+        NULL,                 /* specific     */
+        reg_opt_link_optional /* optional     */
+    },
+    {
+        /* introspect_cls */
+        NULL, /* get_conn_cls */
+        NULL, /* get_cap_flags */
+        NULL, /* opt_query    */
+    },
+    {
+        /* request_cls */
+        NULL, /* wait         */
+        NULL, /* notify       */
+        NULL, /* cancel       */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* free         */
+    },
+    {
+        /* blob_cls */
+        NULL, /* put          */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* token_cls */
+        NULL, /* cmp              */
+        NULL, /* to_str           */
+        NULL  /* from_str         */
+    },
+    NULL /* optional     */
 };
 
-#define NATIVE_VOL_TEST_GROUP_NAME      "test_group"
-#define NATIVE_VOL_TEST_DATASET_NAME    "test_dataset"
-#define NATIVE_VOL_TEST_ATTRIBUTE_NAME  "test_dataset"
-#define NATIVE_VOL_TEST_HARD_LINK_NAME  "test_hard_link"
-#define NATIVE_VOL_TEST_SOFT_LINK_NAME  "test_soft_link"
-#define NATIVE_VOL_TEST_MOVE_LINK_NAME  "test_move_link"
-#define NATIVE_VOL_TEST_COPY_LINK_NAME  "test_copy_link"
-#define NATIVE_VOL_TEST_DATATYPE_NAME   "test_datatype"
-
-#define N_ELEMENTS  10
-
-#define FAKE_VOL_NAME   "fake"
+#define FAKE_VOL_NAME  "fake"
+#define FAKE_VOL_VALUE ((H5VL_class_value_t)501)
 
 /* A VOL class struct that describes a VOL class with no
  * functionality.
  */
 static const H5VL_class_t fake_vol_g = {
-    0,                                              /* version      */
-    (H5VL_class_value_t)501,                        /* value        */
-    FAKE_VOL_NAME,                                  /* name         */
-    0,                                              /* capability flags */
-    NULL,                                           /* initialize   */
-    NULL,                                           /* terminate    */
-    {   /* info_cls */
-        (size_t)0,                                  /* size    */
-        NULL,                                       /* copy    */
-        NULL,                                       /* compare */
-        NULL,                                       /* free    */
-        NULL,                                       /* to_str  */
-        NULL,                                       /* from_str */
+    H5VL_VERSION,   /* VOL class struct version */
+    FAKE_VOL_VALUE, /* value        */
+    FAKE_VOL_NAME,  /* name         */
+    0,              /* connector version */
+    0,              /* capability flags */
+    NULL,           /* initialize   */
+    NULL,           /* terminate    */
+    {
+        /* info_cls */
+        (size_t)0, /* size    */
+        NULL,      /* copy    */
+        NULL,      /* compare */
+        NULL,      /* free    */
+        NULL,      /* to_str  */
+        NULL,      /* from_str */
+    },
+    {
+        /* wrap_cls */
+        NULL, /* get_object   */
+        NULL, /* get_wrap_ctx */
+        NULL, /* wrap_object  */
+        NULL, /* unwrap_object */
+        NULL, /* free_wrap_ctx */
     },
-    {   /* wrap_cls */
-        NULL,                                       /* get_object   */
-        NULL,                                       /* get_wrap_ctx */
-        NULL,                                       /* wrap_object  */
-        NULL,                                       /* unwrap_object */
-        NULL,                                       /* free_wrap_ctx */
+    {
+        /* attribute_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* read         */
+        NULL, /* write        */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
     },
-    {   /* attribute_cls */
-        NULL,                                       /* create       */
-        NULL,                                       /* open         */
-        NULL,                                       /* read         */
-        NULL,                                       /* write        */
-        NULL,                                       /* get          */
-        NULL,                                       /* specific     */
-        NULL,                                       /* optional     */
-        NULL                                        /* close        */
+    {
+        /* dataset_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* read         */
+        NULL, /* write        */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
     },
-    {   /* dataset_cls */
-        NULL,                                       /* create       */
-        NULL,                                       /* open         */
-        NULL,                                       /* read         */
-        NULL,                                       /* write        */
-        NULL,                                       /* get          */
-        NULL,                                       /* specific     */
-        NULL,                                       /* optional     */
-        NULL                                        /* close        */
+    {
+        /* datatype_cls */
+        NULL,                 /* commit       */
+        NULL,                 /* open         */
+        reg_opt_datatype_get, /* get          */
+        NULL,                 /* specific     */
+        NULL,                 /* optional     */
+        NULL                  /* close        */
     },
-    {   /* datatype_cls */
-        NULL,                                       /* commit       */
-        NULL,                                       /* open         */
-        NULL,                                       /* get_size     */
-        NULL,                                       /* specific     */
-        NULL,                                       /* optional     */
-        NULL                                        /* close        */
+    {
+        /* file_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
     },
-    {   /* file_cls */
-        NULL,                                       /* create       */
-        NULL,                                       /* open         */
-        NULL,                                       /* get          */
-        NULL,                                       /* specific     */
-        NULL,                                       /* optional     */
-        NULL                                        /* close        */
+    {
+        /* group_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
     },
-    {   /* group_cls */
-        NULL,                                       /* create       */
-        NULL,                                       /* open         */
-        NULL,                                       /* get          */
-        NULL,                                       /* specific     */
-        NULL,                                       /* optional     */
-        NULL                                        /* close        */
+    {
+        /* link_cls */
+        NULL, /* create       */
+        NULL, /* copy         */
+        NULL, /* move         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
     },
-    {   /* link_cls */
-        NULL,                                       /* create       */
-        NULL,                                       /* copy         */
-        NULL,                                       /* move         */
-        NULL,                                       /* get          */
-        NULL,                                       /* specific     */
-        NULL                                        /* optional     */
+    {
+        /* object_cls */
+        NULL, /* open         */
+        NULL, /* copy         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
     },
-    {   /* object_cls */
-        NULL,                                       /* open         */
-        NULL,                                       /* copy         */
-        NULL,                                       /* get          */
-        NULL,                                       /* specific     */
-        NULL                                        /* optional     */
+    {
+        /* introspect_cls */
+        NULL, /* get_conn_cls */
+        NULL, /* get_cap_flags */
+        NULL, /* opt_query    */
     },
-    {   /* request_cls */
-        NULL,                                       /* wait         */
-        NULL,                                       /* notify       */
-        NULL,                                       /* cancel       */
-        NULL,                                       /* specific     */
-        NULL,                                       /* optional     */
-        NULL                                        /* free         */
+    {
+        /* request_cls */
+        NULL, /* wait         */
+        NULL, /* notify       */
+        NULL, /* cancel       */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* free         */
     },
-    NULL                                            /* optional     */
+    {
+        /* blob_cls */
+        NULL, /* put          */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* token_cls */
+        NULL, /* cmp              */
+        NULL, /* to_str           */
+        NULL  /* from_str         */
+    },
+    NULL /* optional     */
 };
 
-
+static herr_t fake_async_get_cap_flags(const void *info, unsigned *cap_flags);
+
+#define FAKE_ASYNC_VOL_NAME  "fake_async"
+#define FAKE_ASYNC_VOL_VALUE ((H5VL_class_value_t)503)
+
+/* A VOL class struct that describes a VOL class with no
+ * functionality except to set the async capability flag.
+ */
+static const H5VL_class_t fake_async_vol_g = {
+    H5VL_VERSION,         /* VOL class struct version */
+    FAKE_ASYNC_VOL_VALUE, /* value        */
+    FAKE_ASYNC_VOL_NAME,  /* name         */
+    0,                    /* connector version */
+    H5VL_CAP_FLAG_ASYNC,  /* capability flags */
+    NULL,                 /* initialize   */
+    NULL,                 /* terminate    */
+    {
+        /* info_cls */
+        (size_t)0, /* size    */
+        NULL,      /* copy    */
+        NULL,      /* compare */
+        NULL,      /* free    */
+        NULL,      /* to_str  */
+        NULL,      /* from_str */
+    },
+    {
+        /* wrap_cls */
+        NULL, /* get_object   */
+        NULL, /* get_wrap_ctx */
+        NULL, /* wrap_object  */
+        NULL, /* unwrap_object */
+        NULL, /* free_wrap_ctx */
+    },
+    {
+        /* attribute_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* read         */
+        NULL, /* write        */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* dataset_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* read         */
+        NULL, /* write        */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* datatype_cls */
+        NULL, /* commit       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* file_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* group_cls */
+        NULL, /* create       */
+        NULL, /* open         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* close        */
+    },
+    {
+        /* link_cls */
+        NULL, /* create       */
+        NULL, /* copy         */
+        NULL, /* move         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* object_cls */
+        NULL, /* open         */
+        NULL, /* copy         */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* introspect_cls */
+        NULL,                     /* get_conn_cls */
+        fake_async_get_cap_flags, /* get_cap_flags */
+        NULL,                     /* opt_query    */
+    },
+    {
+        /* request_cls */
+        NULL, /* wait         */
+        NULL, /* notify       */
+        NULL, /* cancel       */
+        NULL, /* specific     */
+        NULL, /* optional     */
+        NULL  /* free         */
+    },
+    {
+        /* blob_cls */
+        NULL, /* put          */
+        NULL, /* get          */
+        NULL, /* specific     */
+        NULL  /* optional     */
+    },
+    {
+        /* token_cls */
+        NULL, /* cmp              */
+        NULL, /* to_str           */
+        NULL  /* from_str         */
+    },
+    NULL /* optional     */
+};
+
+/*-------------------------------------------------------------------------
+ * Function:    reg_opt_op_optional_verify
+ *
+ * Purpose:     Common verification routine for dynamic optional operations
+ *
+ * Return:      Success:    0
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+reg_opt_op_optional_verify(void *obj, H5VL_optional_args_t *args)
+{
+    int *o = (int *)obj;
+    int *op_args;
+
+    /* Check for receiving correct operation value */
+    if (args->op_type != reg_opt_curr_op_val)
+        return -1;
+
+    /* Check that the object is correct */
+    if ((-1) != *o)
+        return -1;
+
+    /* Update the object, with the operation value */
+    *o = args->op_type;
+
+    /* Check that the argument is correct */
+    op_args = args->args;
+    if (NULL == op_args)
+        return -1;
+    if ((-1) != *op_args)
+        return -1;
+
+    /* Update the argument return parameter */
+    *op_args = args->op_type;
+
+    return 0;
+} /* end reg_opt_op_optional_verify() */
+
+/*-------------------------------------------------------------------------
+ * Function:    reg_opt_op_optional
+ *
+ * Purpose:     Common callback to perform a connector-specific operation
+ *              on an object
+ *
+ * Return:      Success:    0
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+reg_opt_op_optional(void *obj, H5VL_optional_args_t *args, hid_t H5_ATTR_UNUSED dxpl_id,
+                    void H5_ATTR_UNUSED **req)
+{
+    /* Invoke the common value verification routine */
+    return reg_opt_op_optional_verify(obj, args);
+} /* end reg_opt_op_optional() */
+
+/*-------------------------------------------------------------------------
+ * Function:    reg_opt_link_optional
+ *
+ * Purpose:     Callback to perform a connector-specific operation
+ *              on a link
+ *
+ * Return:      Success:    0
+ *              Failure:    -1
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+reg_opt_link_optional(void *obj, const H5VL_loc_params_t *loc_params, H5VL_optional_args_t *args,
+                      hid_t H5_ATTR_UNUSED dxpl_id, void H5_ATTR_UNUSED **req)
+{
+    /* Check for receiving correct loc_params info */
+    if (loc_params->type != H5VL_OBJECT_BY_NAME)
+        return -1;
+    if (loc_params->obj_type != H5I_GROUP)
+        return -1;
+    if (HDstrcmp(loc_params->loc_data.loc_by_name.name, ".") != 0)
+        return -1;
+    if (loc_params->loc_data.loc_by_name.lapl_id != H5P_LINK_ACCESS_DEFAULT)
+        return -1;
+
+    /* Invoke the common value verification routine */
+    return reg_opt_op_optional_verify(obj, args);
+} /* end reg_opt_link_optional() */
+
+/*-------------------------------------------------------------------------
+ * Function:    reg_opt_datatype_get
+ *
+ * Purpose:     Handles the datatype get callback
+ *
+ * Note:        This is _strictly_ a testing fixture to support the
+ *              exercise_reg_opt_oper() testing routine.  It fakes just
+ *              enough of the named datatype VOL callback for the
+ *              H5VL_register_using_vol_id() call in that test routine to
+ *              succeed.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+reg_opt_datatype_get(void H5_ATTR_UNUSED *obj, H5VL_datatype_get_args_t *args, hid_t H5_ATTR_UNUSED dxpl_id,
+                     void H5_ATTR_UNUSED **req)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    if (H5VL_DATATYPE_GET_BINARY_SIZE == args->op_type) {
+        if (H5Tencode(H5T_NATIVE_INT, NULL, args->args.get_binary_size.size) < 0)
+            ret_value = FAIL;
+    } /* end if */
+    else if (H5VL_DATATYPE_GET_BINARY == args->op_type) {
+        if (H5Tencode(H5T_NATIVE_INT, args->args.get_binary.buf, &args->args.get_binary.buf_size) < 0)
+            ret_value = FAIL;
+    } /* end if */
+    else
+        ret_value = FAIL;
+
+    return ret_value;
+} /* end reg_opt_datatype_get() */
+
+/*-------------------------------------------------------------------------
+ * Function:    fake_async_get_cap_flags
+ *
+ * Purpose:     Return the capability flags for the 'fake async' connector
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+fake_async_get_cap_flags(const void H5_ATTR_UNUSED *info, unsigned *cap_flags)
+{
+    *cap_flags = fake_async_vol_g.cap_flags;
+
+    return SUCCEED;
+} /* end fake_async_get_cap_flags() */
+
 /*-------------------------------------------------------------------------
  * Function:    test_vol_registration()
  *
@@ -148,18 +582,23 @@ static const H5VL_class_t fake_vol_g = {
 static herr_t
 test_vol_registration(void)
 {
-    hid_t native_id = H5I_INVALID_HID;
-    hid_t lapl_id = H5I_INVALID_HID;
-    hid_t vipl_id = H5I_INVALID_HID;
-    herr_t ret = SUCCEED;
-    htri_t is_registered = FAIL;
-    hid_t vol_id = H5I_INVALID_HID;
-    hid_t vol_id2 = H5I_INVALID_HID;
+    hid_t         native_id          = H5I_INVALID_HID;
+    hid_t         lapl_id            = H5I_INVALID_HID;
+    hid_t         vipl_id            = H5I_INVALID_HID;
+    herr_t        ret                = SUCCEED;
+    htri_t        is_registered      = FAIL;
+    hid_t         vol_id             = H5I_INVALID_HID;
+    hid_t         vol_id2            = H5I_INVALID_HID;
+    H5VL_class_t *bad_fake_vol_class = NULL;
 
     TESTING("VOL registration");
 
     /* The test/fake VOL connector should not be registered at the start of the test */
-    if ((is_registered = H5VLis_connector_registered(FAKE_VOL_NAME)) < 0)
+    if ((is_registered = H5VLis_connector_registered_by_name(FAKE_VOL_NAME)) < 0)
+        TEST_ERROR;
+    if (is_registered > 0)
+        FAIL_PUTS_ERROR("VOL connector is inappropriately registered");
+    if ((is_registered = H5VLis_connector_registered_by_value(FAKE_VOL_VALUE)) < 0)
         TEST_ERROR;
     if (is_registered > 0)
         FAIL_PUTS_ERROR("VOL connector is inappropriately registered");
@@ -167,14 +606,31 @@ test_vol_registration(void)
     /* Test registering a connector with an incorrect property list (SHOULD FAIL) */
     if ((lapl_id = H5Pcreate(H5P_LINK_ACCESS)) < 0)
         TEST_ERROR;
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         vol_id = H5VLregister_connector(&fake_vol_g, lapl_id);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
     if (H5I_INVALID_HID != vol_id)
         FAIL_PUTS_ERROR("should not be able to register a connector with an incorrect property list");
     if (H5Pclose(lapl_id) < 0)
         TEST_ERROR;
 
+    /* Test registering a VOL connector with an incompatible version # */
+    if (NULL == (bad_fake_vol_class = HDmalloc(sizeof(H5VL_class_t))))
+        TEST_ERROR;
+    HDmemcpy(bad_fake_vol_class, &fake_vol_g, sizeof(H5VL_class_t));
+    bad_fake_vol_class->version = H5VL_VERSION + 1;
+    H5E_BEGIN_TRY
+    {
+        vol_id = H5VLregister_connector(bad_fake_vol_class, H5P_DEFAULT);
+    }
+    H5E_END_TRY;
+    if (H5I_INVALID_HID != vol_id)
+        FAIL_PUTS_ERROR("should not be able to register a connector with an incompatible version #");
+    HDfree(bad_fake_vol_class);
+    bad_fake_vol_class = NULL;
+
     /* Load a VOL interface
      * The vipl_id does nothing without a VOL that needs it, but we do need to
      * test creating a property list of that class and passing it along as a
@@ -188,7 +644,11 @@ test_vol_registration(void)
         TEST_ERROR;
 
     /* The test/fake VOL connector should be registered now */
-    if ((is_registered = H5VLis_connector_registered(FAKE_VOL_NAME)) < 0)
+    if ((is_registered = H5VLis_connector_registered_by_name(FAKE_VOL_NAME)) < 0)
+        TEST_ERROR;
+    if (0 == is_registered)
+        FAIL_PUTS_ERROR("VOL connector is un-registered");
+    if ((is_registered = H5VLis_connector_registered_by_value(FAKE_VOL_VALUE)) < 0)
         TEST_ERROR;
     if (0 == is_registered)
         FAIL_PUTS_ERROR("VOL connector is un-registered");
@@ -198,7 +658,11 @@ test_vol_registration(void)
         TEST_ERROR;
 
     /* The test/fake VOL connector should still be registered now */
-    if ((is_registered = H5VLis_connector_registered(FAKE_VOL_NAME)) < 0)
+    if ((is_registered = H5VLis_connector_registered_by_name(FAKE_VOL_NAME)) < 0)
+        TEST_ERROR;
+    if (0 == is_registered)
+        FAIL_PUTS_ERROR("VOL connector is un-registered");
+    if ((is_registered = H5VLis_connector_registered_by_value(FAKE_VOL_VALUE)) < 0)
         TEST_ERROR;
     if (0 == is_registered)
         FAIL_PUTS_ERROR("VOL connector is un-registered");
@@ -208,7 +672,11 @@ test_vol_registration(void)
         TEST_ERROR;
 
     /* The test/fake VOL connector should still be registered now */
-    if ((is_registered = H5VLis_connector_registered(FAKE_VOL_NAME)) < 0)
+    if ((is_registered = H5VLis_connector_registered_by_name(FAKE_VOL_NAME)) < 0)
+        TEST_ERROR;
+    if (0 == is_registered)
+        FAIL_PUTS_ERROR("VOL connector is un-registered");
+    if ((is_registered = H5VLis_connector_registered_by_value(FAKE_VOL_VALUE)) < 0)
         TEST_ERROR;
     if (0 == is_registered)
         FAIL_PUTS_ERROR("VOL connector is un-registered");
@@ -218,11 +686,13 @@ test_vol_registration(void)
         TEST_ERROR;
 
     /* Try to unregister the native VOL connector (should fail) */
-    if (H5I_INVALID_HID == (native_id = H5VLget_connector_id(H5VL_NATIVE_NAME)))
+    if (H5I_INVALID_HID == (native_id = H5VLget_connector_id_by_name(H5VL_NATIVE_NAME)))
         TEST_ERROR;
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         ret = H5VLunregister_connector(native_id);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
     if (FAIL != ret)
         FAIL_PUTS_ERROR("should not be able to unregister the native VOL connector");
 
@@ -230,16 +700,20 @@ test_vol_registration(void)
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5VLunregister_connector(vol_id);
         H5Pclose(lapl_id);
         H5Pclose(vipl_id);
-    } H5E_END_TRY;
-    return FAIL;
+    }
+    H5E_END_TRY;
+
+    if (bad_fake_vol_class)
+        HDfree(bad_fake_vol_class);
 
+    return FAIL;
 } /* end test_vol_registration() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_native_vol_init()
  *
@@ -257,7 +731,12 @@ test_native_vol_init(void)
     TESTING("Native VOL connector initialization");
 
     /* The native VOL connector should always be registered */
-    if ((is_registered = H5VLis_connector_registered(H5VL_NATIVE_NAME)) < 0)
+    if ((is_registered = H5VLis_connector_registered_by_name(H5VL_NATIVE_NAME)) < 0)
+        TEST_ERROR;
+    if (0 == is_registered)
+        FAIL_PUTS_ERROR("native VOL connector is un-registered");
+
+    if ((is_registered = H5VLis_connector_registered_by_value(H5VL_NATIVE_VALUE)) < 0)
         TEST_ERROR;
     if (0 == is_registered)
         FAIL_PUTS_ERROR("native VOL connector is un-registered");
@@ -270,7 +749,6 @@ error:
 
 } /* end test_native_vol_init() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_file_operation()
  *
@@ -283,20 +761,20 @@ error:
 static herr_t
 test_basic_file_operation(const char *env_h5_drvr)
 {
-    hid_t fid           = H5I_INVALID_HID;
-    hid_t fid_reopen    = H5I_INVALID_HID;
-    hid_t fapl_id       = H5I_INVALID_HID;
-    hid_t fapl_id2      = H5I_INVALID_HID;
-    hid_t fcpl_id       = H5I_INVALID_HID;
-
-    char            filename[1024];
-    ssize_t         obj_count;
-    hid_t           obj_id_list[1];
-    hsize_t         file_size;
-    unsigned        intent;
-    void           *os_file_handle = NULL;
-    H5F_info2_t     finfo;
-    char            name[32];
+    hid_t fid        = H5I_INVALID_HID;
+    hid_t fid_reopen = H5I_INVALID_HID;
+    hid_t fapl_id    = H5I_INVALID_HID;
+    hid_t fapl_id2   = H5I_INVALID_HID;
+    hid_t fcpl_id    = H5I_INVALID_HID;
+
+    char        filename[1024];
+    ssize_t     obj_count;
+    hid_t       obj_id_list[1];
+    hsize_t     file_size;
+    unsigned    intent;
+    void *      os_file_handle = NULL;
+    H5F_info2_t finfo;
+    char        name[32];
 
     TESTING("Basic VOL file operations");
 
@@ -313,9 +791,9 @@ test_basic_file_operation(const char *env_h5_drvr)
      *  I'm not fighting it, just getting the testing to verify that the VOL
      *  connector property is returned correctly.  -QAK, 2018/11/17
      */
-    if(H5Pset_fclose_degree(fapl_id, H5F_CLOSE_SEMI) < 0)
+    if (H5Pset_fclose_degree(fapl_id, H5F_CLOSE_SEMI) < 0)
         TEST_ERROR;
-    if(H5Pset_metadata_read_attempts(fapl_id, 9) < 0)
+    if (H5Pset_metadata_read_attempts(fapl_id, 9) < 0)
         TEST_ERROR
 
     /* H5Fcreate */
@@ -336,8 +814,11 @@ test_basic_file_operation(const char *env_h5_drvr)
     if ((obj_count = H5Fget_obj_ids((hid_t)H5F_OBJ_ALL, H5F_OBJ_DATASET, 2, obj_id_list)) < 0)
         TEST_ERROR;
 
-    /* Can't compare VFD properties for split / multi / family VFDs */
-    if((hbool_t)(HDstrcmp(env_h5_drvr, "split") && HDstrcmp(env_h5_drvr, "multi") && HDstrcmp(env_h5_drvr, "family"))) {
+    /* Can't compare VFD properties for several VFDs */
+    if ((hbool_t)(HDstrcmp(env_h5_drvr, "split") != 0 && HDstrcmp(env_h5_drvr, "multi") != 0 &&
+                  HDstrcmp(env_h5_drvr, "family") != 0 && HDstrcmp(env_h5_drvr, "direct") != 0 &&
+                  HDstrcmp(env_h5_drvr, "core") != 0 && HDstrcmp(env_h5_drvr, "core_paged") != 0 &&
+                  HDstrcmp(env_h5_drvr, "mpio") != 0 && HDstrcmp(env_h5_drvr, "splitter") != 0)) {
         /* H5Fget_access_plist */
         if ((fapl_id2 = H5Fget_access_plist(fid)) < 0)
             TEST_ERROR;
@@ -358,7 +839,8 @@ test_basic_file_operation(const char *env_h5_drvr)
         TEST_ERROR;
 
     /* Can't retrieve VFD handle for split / multi / family VFDs */
-    if((hbool_t)(HDstrcmp(env_h5_drvr, "split") && HDstrcmp(env_h5_drvr, "multi") && HDstrcmp(env_h5_drvr, "family"))) {
+    if ((hbool_t)(HDstrcmp(env_h5_drvr, "split") != 0 && HDstrcmp(env_h5_drvr, "multi") != 0 &&
+                  HDstrcmp(env_h5_drvr, "family") != 0)) {
         /* H5Fget_vfd_handle */
         if (H5Fget_vfd_handle(fid, H5P_DEFAULT, &os_file_handle) < 0)
             TEST_ERROR;
@@ -396,28 +878,34 @@ test_basic_file_operation(const char *env_h5_drvr)
     if ((fid = H5Fopen(filename, H5F_ACC_RDWR, fapl_id)) < 0)
         TEST_ERROR;
 
-    /* Can't compare VFD properties for split / multi / family VFDs */
-    if((hbool_t)(HDstrcmp(env_h5_drvr, "split") && HDstrcmp(env_h5_drvr, "multi") && HDstrcmp(env_h5_drvr, "family"))) {
+    /* Can't compare VFD properties for several VFDs */
+    if ((hbool_t)(HDstrcmp(env_h5_drvr, "split") != 0 && HDstrcmp(env_h5_drvr, "multi") != 0 &&
+                  HDstrcmp(env_h5_drvr, "family") != 0 && HDstrcmp(env_h5_drvr, "direct") != 0 &&
+                  HDstrcmp(env_h5_drvr, "core") != 0 && HDstrcmp(env_h5_drvr, "core_paged") != 0 &&
+                  HDstrcmp(env_h5_drvr, "mpio") != 0 && HDstrcmp(env_h5_drvr, "splitter") != 0)) {
         /* H5Fget_access_plist */
-        if((fapl_id2 = H5Fget_access_plist(fid)) < 0)
+        if ((fapl_id2 = H5Fget_access_plist(fid)) < 0)
             TEST_ERROR;
-        if(H5Pequal(fapl_id, fapl_id2) != TRUE)
+        if (H5Pequal(fapl_id, fapl_id2) != TRUE)
             TEST_ERROR;
-        if(H5Pclose(fapl_id2) < 0)
+        if (H5Pclose(fapl_id2) < 0)
             TEST_ERROR;
     } /* end if */
 
     if ((fid_reopen = H5Freopen(fid)) < 0)
         TEST_ERROR;
 
-    /* Can't compare VFD properties for split / multi / family VFDs */
-    if((hbool_t)(HDstrcmp(env_h5_drvr, "split") && HDstrcmp(env_h5_drvr, "multi") && HDstrcmp(env_h5_drvr, "family"))) {
+    /* Can't compare VFD properties for several VFDs */
+    if ((hbool_t)(HDstrcmp(env_h5_drvr, "split") != 0 && HDstrcmp(env_h5_drvr, "multi") != 0 &&
+                  HDstrcmp(env_h5_drvr, "family") != 0 && HDstrcmp(env_h5_drvr, "direct") != 0 &&
+                  HDstrcmp(env_h5_drvr, "core") != 0 && HDstrcmp(env_h5_drvr, "core_paged") != 0 &&
+                  HDstrcmp(env_h5_drvr, "mpio") != 0 && HDstrcmp(env_h5_drvr, "splitter") != 0)) {
         /* H5Fget_access_plist */
-        if((fapl_id2 = H5Fget_access_plist(fid_reopen)) < 0)
+        if ((fapl_id2 = H5Fget_access_plist(fid_reopen)) < 0)
             TEST_ERROR;
-        if(H5Pequal(fapl_id, fapl_id2) != TRUE)
+        if (H5Pequal(fapl_id, fapl_id2) != TRUE)
             TEST_ERROR;
-        if(H5Pclose(fapl_id2) < 0)
+        if (H5Pclose(fapl_id2) < 0)
             TEST_ERROR;
     } /* end if */
 
@@ -436,19 +924,20 @@ test_basic_file_operation(const char *env_h5_drvr)
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Fclose(fid);
         H5Fclose(fid_reopen);
         H5Pclose(fapl_id);
         H5Pclose(fapl_id2);
         H5Pclose(fcpl_id);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_file_operation() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_group_operation()
  *
@@ -459,14 +948,14 @@ error:
  *-------------------------------------------------------------------------
  */
 static herr_t
-test_basic_group_operation(void)
+test_basic_group_operation(const char *env_h5_drvr)
 {
-    hid_t fid = H5I_INVALID_HID;
-    hid_t fapl_id = H5I_INVALID_HID;
-    hid_t gid = H5I_INVALID_HID;
-    hid_t gid_a = H5I_INVALID_HID;
-    hid_t gcpl_id = H5I_INVALID_HID;
-    char filename[1024];
+    hid_t      fid     = H5I_INVALID_HID;
+    hid_t      fapl_id = H5I_INVALID_HID;
+    hid_t      gid     = H5I_INVALID_HID;
+    hid_t      gid_a   = H5I_INVALID_HID;
+    hid_t      gcpl_id = H5I_INVALID_HID;
+    char       filename[1024];
     H5G_info_t info;
 
     TESTING("Basic VOL group operations");
@@ -502,9 +991,10 @@ test_basic_group_operation(void)
     if (H5Gget_info_by_idx(fid, "/", H5_INDEX_NAME, H5_ITER_NATIVE, 0, &info, H5P_DEFAULT) < 0)
         TEST_ERROR;
 
-    /* H5Gflush */
-    if (H5Gflush(gid) < 0)
-        TEST_ERROR;
+    /* H5Gflush - skip for MPIO file driver as flush calls cause assertions in the library */
+    if (HDstrcmp(env_h5_drvr, "mpio") != 0)
+        if (H5Gflush(gid) < 0)
+            TEST_ERROR;
 
     /* H5Gclose */
     if (H5Gclose(gid) < 0)
@@ -539,18 +1029,19 @@ test_basic_group_operation(void)
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Fclose(fid);
         H5Gclose(gid);
         H5Pclose(fapl_id);
         H5Pclose(gcpl_id);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_group_operation() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_dataset_operation()
  *
@@ -561,24 +1052,24 @@ error:
  *-------------------------------------------------------------------------
  */
 static herr_t
-test_basic_dataset_operation(void)
+test_basic_dataset_operation(const char *env_h5_drvr)
 {
-    hid_t fid       = H5I_INVALID_HID;
-    hid_t fapl_id   = H5I_INVALID_HID;
-    hid_t dcpl_id   = H5I_INVALID_HID;
-    hid_t dapl_id   = H5I_INVALID_HID;
-    hid_t did       = H5I_INVALID_HID;
-    hid_t did_a     = H5I_INVALID_HID;
-    hid_t sid       = H5I_INVALID_HID;
-    hid_t tid       = H5I_INVALID_HID;
+    hid_t fid     = H5I_INVALID_HID;
+    hid_t fapl_id = H5I_INVALID_HID;
+    hid_t dcpl_id = H5I_INVALID_HID;
+    hid_t dapl_id = H5I_INVALID_HID;
+    hid_t did     = H5I_INVALID_HID;
+    hid_t did_a   = H5I_INVALID_HID;
+    hid_t sid     = H5I_INVALID_HID;
+    hid_t tid     = H5I_INVALID_HID;
 
     char filename[1024];
 
-    hsize_t curr_dims   = 0;
-    hsize_t max_dims    = H5S_UNLIMITED;
+    hsize_t curr_dims = 0;
+    hsize_t max_dims  = H5S_UNLIMITED;
 
-    hsize_t storage_size;
-    haddr_t offset;
+    hsize_t            storage_size;
+    haddr_t            offset;
     H5D_space_status_t status;
 
     int in_buf[N_ELEMENTS];
@@ -595,7 +1086,7 @@ test_basic_dataset_operation(void)
     if ((fid = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl_id)) < 0)
         TEST_ERROR;
     for (i = 0; i < N_ELEMENTS; i++) {
-        in_buf[i] = i;
+        in_buf[i]  = i;
         out_buf[i] = 0;
     }
 
@@ -608,7 +1099,8 @@ test_basic_dataset_operation(void)
         TEST_ERROR;
     if (H5Pset_chunk(dcpl_id, 1, &curr_dims) < 0)
         TEST_ERROR;
-    if ((did = H5Dcreate2(fid, NATIVE_VOL_TEST_DATASET_NAME, H5T_NATIVE_INT, sid, H5P_DEFAULT, dcpl_id, H5P_DEFAULT)) < 0)
+    if ((did = H5Dcreate2(fid, NATIVE_VOL_TEST_DATASET_NAME, H5T_NATIVE_INT, sid, H5P_DEFAULT, dcpl_id,
+                          H5P_DEFAULT)) < 0)
         TEST_ERROR;
 
     /* H5Dcreate_anon */
@@ -625,9 +1117,10 @@ test_basic_dataset_operation(void)
     if (H5Dset_extent(did, &curr_dims) < 0)
         TEST_ERROR;
 
-    /* H5Dflush */
-    if (H5Dflush(did) < 0)
-        TEST_ERROR;
+    /* H5Dflush - skip for MPIO file driver as flush calls cause assertions in the library */
+    if (HDstrcmp(env_h5_drvr, "mpio") != 0)
+        if (H5Dflush(did) < 0)
+            TEST_ERROR;
 
     /* H5Dwrite */
     if (H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, in_buf) < 0)
@@ -716,7 +1209,8 @@ test_basic_dataset_operation(void)
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Fclose(fid);
         H5Dclose(did);
         H5Dclose(did_a);
@@ -725,13 +1219,13 @@ error:
         H5Pclose(fapl_id);
         H5Pclose(dapl_id);
         H5Pclose(dcpl_id);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_dataset_operation() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_attribute_operation()
  *
@@ -744,19 +1238,19 @@ error:
 static herr_t
 test_basic_attribute_operation(void)
 {
-    hid_t fid       = H5I_INVALID_HID;
-    hid_t fapl_id   = H5I_INVALID_HID;
-    hid_t gid       = H5I_INVALID_HID;
-    hid_t aid       = H5I_INVALID_HID;
-    hid_t aid_name  = H5I_INVALID_HID;
-    hid_t sid       = H5I_INVALID_HID;
+    hid_t fid      = H5I_INVALID_HID;
+    hid_t fapl_id  = H5I_INVALID_HID;
+    hid_t gid      = H5I_INVALID_HID;
+    hid_t aid      = H5I_INVALID_HID;
+    hid_t aid_name = H5I_INVALID_HID;
+    hid_t sid      = H5I_INVALID_HID;
 
-    char    filename[1024];
+    char filename[1024];
 
-    hsize_t dims    = 1;
+    hsize_t dims = 1;
 
-    int     data_in     = 42;
-    int     data_out    = 0;
+    int data_in  = 42;
+    int data_out = 0;
 
     TESTING("Basic VOL attribute operations");
 
@@ -773,7 +1267,8 @@ test_basic_attribute_operation(void)
         TEST_ERROR;
 
     /* H5Acreate */
-    if ((aid = H5Acreate2(fid, NATIVE_VOL_TEST_ATTRIBUTE_NAME, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+    if ((aid = H5Acreate2(fid, NATIVE_VOL_TEST_ATTRIBUTE_NAME, H5T_NATIVE_INT, sid, H5P_DEFAULT,
+                          H5P_DEFAULT)) < 0)
         TEST_ERROR;
 
     /* H5Awrite */
@@ -801,7 +1296,8 @@ test_basic_attribute_operation(void)
         TEST_ERROR;
 
     /* H5Acreate_by_name */
-    if ((aid_name = H5Acreate_by_name(fid, NATIVE_VOL_TEST_GROUP_NAME, NATIVE_VOL_TEST_ATTRIBUTE_NAME, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+    if ((aid_name = H5Acreate_by_name(fid, NATIVE_VOL_TEST_GROUP_NAME, NATIVE_VOL_TEST_ATTRIBUTE_NAME,
+                                      H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR;
     /* H5Aclose */
     if (H5Aclose(aid_name) < 0)
@@ -828,20 +1324,21 @@ test_basic_attribute_operation(void)
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Fclose(fid);
         H5Pclose(fapl_id);
         H5Gclose(gid);
         H5Sclose(sid);
         H5Aclose(aid);
         H5Aclose(aid_name);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_attribute_operation() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_object_operation()
  *
@@ -854,13 +1351,13 @@ error:
 static herr_t
 test_basic_object_operation(void)
 {
-    hid_t fid       = H5I_INVALID_HID;
-    hid_t fapl_id   = H5I_INVALID_HID;
-    hid_t gid       = H5I_INVALID_HID;
-    hid_t oid       = H5I_INVALID_HID;
+    hid_t fid     = H5I_INVALID_HID;
+    hid_t fapl_id = H5I_INVALID_HID;
+    hid_t gid     = H5I_INVALID_HID;
+    hid_t oid     = H5I_INVALID_HID;
 
-    char filename[1024];
-    H5O_info_t object_info;
+    char        filename[1024];
+    H5O_info2_t object_info;
 
     TESTING("Basic VOL object operations");
 
@@ -874,27 +1371,31 @@ test_basic_object_operation(void)
         TEST_ERROR;
 
     /* H5Oget_info */
-    if (H5Oget_info2(fid, &object_info, H5O_INFO_ALL) < 0)
+    if (H5Oget_info3(fid, &object_info, H5O_INFO_ALL) < 0)
         TEST_ERROR;
 
+    //! [H5Oget_info_by_name3_snip]
+
     /* H5Oget_info_by_name */
-    if (H5Oget_info_by_name2(fid, NATIVE_VOL_TEST_GROUP_NAME, &object_info, H5O_INFO_ALL, H5P_DEFAULT) < 0)
+    if (H5Oget_info_by_name3(fid, NATIVE_VOL_TEST_GROUP_NAME, &object_info, H5O_INFO_ALL, H5P_DEFAULT) < 0)
         TEST_ERROR;
 
+    //! [H5Oget_info_by_name3_snip]
+
     /* H5Oexists_by_name */
-    if (H5Oexists_by_name(fid, NATIVE_VOL_TEST_GROUP_NAME, H5P_DEFAULT) != TRUE) 
+    if (H5Oexists_by_name(fid, NATIVE_VOL_TEST_GROUP_NAME, H5P_DEFAULT) != TRUE)
         TEST_ERROR;
 
     /* H5Oopen/close */
-    if ((oid = H5Oopen(fid, NATIVE_VOL_TEST_GROUP_NAME, H5P_DEFAULT)) < 0) 
+    if ((oid = H5Oopen(fid, NATIVE_VOL_TEST_GROUP_NAME, H5P_DEFAULT)) < 0)
         TEST_ERROR;
     if (H5Oclose(oid) < 0)
         TEST_ERROR;
 
-    if (H5Fclose(fid) < 0)
-        TEST_ERROR;
     if (H5Gclose(gid) < 0)
         TEST_ERROR;
+    if (H5Fclose(fid) < 0)
+        TEST_ERROR;
 
     h5_delete_test_file(FILENAME[0], fapl_id);
 
@@ -902,22 +1403,22 @@ test_basic_object_operation(void)
     if (H5Pclose(fapl_id) < 0)
         TEST_ERROR;
 
-
     PASSED();
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Fclose(fid);
         H5Pclose(fapl_id);
         H5Gclose(gid);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_object_operation() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_link_operation()
  *
@@ -930,10 +1431,10 @@ error:
 static herr_t
 test_basic_link_operation(void)
 {
-    hid_t fid       = H5I_INVALID_HID;
-    hid_t gid       = H5I_INVALID_HID;
-    hid_t fapl_id   = H5I_INVALID_HID;
-    char filename[1024];
+    hid_t fid     = H5I_INVALID_HID;
+    hid_t gid     = H5I_INVALID_HID;
+    hid_t fapl_id = H5I_INVALID_HID;
+    char  filename[1024];
 
     TESTING("Basic VOL link operations");
 
@@ -961,17 +1462,19 @@ test_basic_link_operation(void)
         TEST_ERROR;
 
     /* H5Lcopy */
-    if (H5Lcopy(gid, NATIVE_VOL_TEST_HARD_LINK_NAME, fid, NATIVE_VOL_TEST_COPY_LINK_NAME, H5P_DEFAULT, H5P_DEFAULT) < 0)
+    if (H5Lcopy(gid, NATIVE_VOL_TEST_HARD_LINK_NAME, fid, NATIVE_VOL_TEST_COPY_LINK_NAME, H5P_DEFAULT,
+                H5P_DEFAULT) < 0)
         TEST_ERROR;
 
     /* H5Lmove */
-    if (H5Lmove(fid, NATIVE_VOL_TEST_COPY_LINK_NAME, gid, NATIVE_VOL_TEST_MOVE_LINK_NAME, H5P_DEFAULT, H5P_DEFAULT) < 0)
+    if (H5Lmove(fid, NATIVE_VOL_TEST_COPY_LINK_NAME, gid, NATIVE_VOL_TEST_MOVE_LINK_NAME, H5P_DEFAULT,
+                H5P_DEFAULT) < 0)
         TEST_ERROR;
 
-    if (H5Fclose(fid) < 0)
-        TEST_ERROR;
     if (H5Gclose(gid) < 0)
         TEST_ERROR;
+    if (H5Fclose(fid) < 0)
+        TEST_ERROR;
 
     h5_delete_test_file(FILENAME[0], fapl_id);
 
@@ -979,22 +1482,22 @@ test_basic_link_operation(void)
     if (H5Pclose(fapl_id) < 0)
         TEST_ERROR;
 
-
     PASSED();
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Fclose(fid);
         H5Fclose(gid);
         H5Pclose(fapl_id);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_link_operation() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    test_basic_datatype_operation()
  *
@@ -1005,14 +1508,14 @@ error:
  *-------------------------------------------------------------------------
  */
 static herr_t
-test_basic_datatype_operation(void)
+test_basic_datatype_operation(const char *env_h5_drvr)
 {
-    hid_t fid       = H5I_INVALID_HID;
-    hid_t fapl_id   = H5I_INVALID_HID;
-    hid_t tid       = H5I_INVALID_HID;
-    hid_t tid_anon  = H5I_INVALID_HID;
-    hid_t tcpl_id   = H5I_INVALID_HID;
-    char filename[1024];
+    hid_t fid      = H5I_INVALID_HID;
+    hid_t fapl_id  = H5I_INVALID_HID;
+    hid_t tid      = H5I_INVALID_HID;
+    hid_t tid_anon = H5I_INVALID_HID;
+    hid_t tcpl_id  = H5I_INVALID_HID;
+    char  filename[1024];
 
     TESTING("Basic VOL datatype operations");
 
@@ -1029,9 +1532,10 @@ test_basic_datatype_operation(void)
     if (H5Tcommit2(fid, NATIVE_VOL_TEST_DATATYPE_NAME, tid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT) < 0)
         TEST_ERROR;
 
-    /* H5Tflush */
-    if (H5Tflush(tid) < 0)
-        TEST_ERROR;
+    /* H5Tflush - skip for MPIO file driver as flush calls cause assertions in the library */
+    if (HDstrcmp(env_h5_drvr, "mpio") != 0)
+        if (H5Tflush(tid) < 0)
+            TEST_ERROR;
 
     /* H5Trefresh */
     if (H5Trefresh(tid) < 0)
@@ -1074,19 +1578,533 @@ test_basic_datatype_operation(void)
     return SUCCEED;
 
 error:
-    H5E_BEGIN_TRY {
+    H5E_BEGIN_TRY
+    {
         H5Pclose(tcpl_id);
         H5Fclose(fid);
         H5Pclose(fapl_id);
         H5Tclose(tid);
         H5Tclose(tid_anon);
-    } H5E_END_TRY;
+    }
+    H5E_END_TRY;
 
     return FAIL;
 
 } /* end test_basic_datatype_operation() */
 
-
+typedef herr_t (*reg_opt_obj_oper_t)(const char *app_file, const char *app_func, unsigned app_line,
+                                     hid_t obj_id, H5VL_optional_args_t *args, hid_t dxpl_id, hid_t es_id);
+typedef herr_t (*reg_opt_link_oper_t)(const char *app_file, const char *app_func, unsigned app_line,
+                                      hid_t obj_id, const char *name, hid_t lapl_id,
+                                      H5VL_optional_args_t *args, hid_t dxpl_id, hid_t es_id);
+typedef union {
+    reg_opt_obj_oper_t  obj_op;
+    reg_opt_link_oper_t link_op;
+} reg_opt_oper_t;
+
+/*-------------------------------------------------------------------------
+ * Function:    exercise_reg_opt_oper()
+ *
+ * Purpose:     Exercise a particular optional operation for a type.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+exercise_reg_opt_oper(hid_t fake_vol_id, hid_t reg_opt_vol_id, H5VL_subclass_t subcls,
+                      const char *subcls_name, H5I_type_t id_type, reg_opt_oper_t reg_opt_op)
+{
+    char                 op_name[256]; /* Operation name to register */
+    hid_t                obj_id = H5I_INVALID_HID;
+    H5VL_object_t *      vol_obj;
+    H5VL_optional_args_t vol_cb_args;
+    int                  fake_obj, fake_arg;
+    int                  op_val = -1, op_val2 = -1;
+    int                  find_op_val;
+    herr_t               ret = SUCCEED;
+
+    /* Test registering optional operation */
+    HDsnprintf(op_name, sizeof(op_name), "%s-op1", subcls_name);
+    if (H5VLregister_opt_operation(subcls, op_name, &op_val) < 0)
+        TEST_ERROR;
+
+    /* Verify that the reserved amount of optional operations is obeyed */
+    /* (The first optional operation registered should be at the lower limit) */
+    if (op_val != H5VL_RESERVED_NATIVE_OPTIONAL)
+        TEST_ERROR;
+
+    /* Look up 1st registered optional operation */
+    find_op_val = 0;
+    if (H5VLfind_opt_operation(subcls, op_name, &find_op_val) < 0)
+        TEST_ERROR;
+
+    /* Verify that the operation was looked up successfully */
+    if (op_val != find_op_val)
+        TEST_ERROR;
+
+    /* Test registering second optional operation */
+    HDsnprintf(op_name, sizeof(op_name), "%s-op2", subcls_name);
+    if (H5VLregister_opt_operation(subcls, op_name, &op_val2) < 0)
+        TEST_ERROR;
+
+    /* Verify that the reserved amount of optional operations is obeyed */
+    /* (The 2nd optional operation registered should be at the lower limit + 1) */
+    if (op_val2 != (H5VL_RESERVED_NATIVE_OPTIONAL + 1))
+        TEST_ERROR;
+
+    /* Look up 2nd registered optional operation */
+    find_op_val = 0;
+    if (H5VLfind_opt_operation(subcls, op_name, &find_op_val) < 0)
+        TEST_ERROR;
+
+    /* Verify that the operation was looked up successfully */
+    if (op_val2 != find_op_val)
+        TEST_ERROR;
+
+    /* Push a new API context on the stack */
+    /* (Necessary for the named datatype construction routines) */
+    if (H5VL_SUBCLS_DATATYPE == subcls)
+        H5CX_push();
+
+    /* Create fake object on fake VOL connector */
+    if (H5I_INVALID_HID == (obj_id = H5VL_register_using_vol_id(id_type, &fake_obj, fake_vol_id, TRUE)))
+        TEST_ERROR;
+
+    /* Pop the API context off the stack */
+    if (H5VL_SUBCLS_DATATYPE == subcls)
+        H5CX_pop(FALSE);
+
+    /* Attempt to issue operation on fake VOL connector */
+    fake_obj            = -1;
+    fake_arg            = -1;
+    vol_cb_args.op_type = op_val;
+    vol_cb_args.args    = &fake_arg;
+    H5E_BEGIN_TRY
+    {
+        if (H5VL_SUBCLS_LINK == subcls || H5VL_SUBCLS_OBJECT == subcls)
+            ret = (*reg_opt_op.link_op)(__FILE__, __func__, __LINE__, obj_id, ".", H5P_DEFAULT, &vol_cb_args,
+                                        H5P_DEFAULT, H5ES_NONE);
+        else
+            ret = (*reg_opt_op.obj_op)(__FILE__, __func__, __LINE__, obj_id, &vol_cb_args, H5P_DEFAULT,
+                                       H5ES_NONE);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to perform an optional operation with a NULL callback");
+    if ((-1) != fake_obj)
+        FAIL_PUTS_ERROR("'fake_obj' changed during failed operation?");
+    if ((-1) != fake_arg)
+        FAIL_PUTS_ERROR("'fake_arg' changed during failed operation?");
+
+    /* Named datatypes must be destroyed differently */
+    if (H5VL_SUBCLS_DATATYPE == subcls) {
+        H5T_t *dt;
+
+        /* Destroy fake datatype object */
+        if (NULL == (dt = H5I_remove(obj_id)))
+            TEST_ERROR;
+        if (H5VL_free_object(dt->vol_obj) < 0)
+            TEST_ERROR;
+        dt->vol_obj = NULL;
+        if (H5T_close(dt) < 0)
+            TEST_ERROR;
+    } /* end if */
+    else {
+        /* Destroy fake object */
+        if (NULL == (vol_obj = H5I_remove(obj_id)))
+            TEST_ERROR;
+        if (H5VL_free_object(vol_obj) < 0)
+            TEST_ERROR;
+    } /* end else */
+
+    /* Push a new API context on the stack */
+    /* (Necessary for the named datatype construction routines) */
+    if (H5VL_SUBCLS_DATATYPE == subcls)
+        H5CX_push();
+
+    /* Create fake object on reg_opt VOL connector */
+    if (H5I_INVALID_HID == (obj_id = H5VL_register_using_vol_id(id_type, &fake_obj, reg_opt_vol_id, TRUE)))
+        TEST_ERROR;
+
+    /* Pop the API context off the stack */
+    if (H5VL_SUBCLS_DATATYPE == subcls)
+        H5CX_pop(FALSE);
+
+    /* Issue first operation */
+    fake_obj            = -1;
+    fake_arg            = -1;
+    reg_opt_curr_op_val = op_val;
+    vol_cb_args.op_type = op_val;
+    vol_cb_args.args    = &fake_arg;
+    if (H5VL_SUBCLS_LINK == subcls || H5VL_SUBCLS_OBJECT == subcls)
+        ret = (*reg_opt_op.link_op)(__FILE__, __func__, __LINE__, obj_id, ".", H5P_DEFAULT, &vol_cb_args,
+                                    H5P_DEFAULT, H5ES_NONE);
+    else
+        ret =
+            (*reg_opt_op.obj_op)(__FILE__, __func__, __LINE__, obj_id, &vol_cb_args, H5P_DEFAULT, H5ES_NONE);
+    if (ret < 0)
+        TEST_ERROR;
+
+    /* Verify that fake object & argument were modified correctly */
+    if (op_val != fake_obj)
+        FAIL_PUTS_ERROR("'fake_obj' not updated");
+    if (op_val != fake_arg)
+        FAIL_PUTS_ERROR("'fake_arg' not updated");
+
+    /* Issue second operation */
+    fake_obj            = -1;
+    fake_arg            = -1;
+    reg_opt_curr_op_val = op_val2;
+    vol_cb_args.op_type = op_val2;
+    vol_cb_args.args    = &fake_arg;
+    if (H5VL_SUBCLS_LINK == subcls || H5VL_SUBCLS_OBJECT == subcls)
+        ret = (*reg_opt_op.link_op)(__FILE__, __func__, __LINE__, obj_id, ".", H5P_DEFAULT, &vol_cb_args,
+                                    H5P_DEFAULT, H5ES_NONE);
+    else
+        ret =
+            (*reg_opt_op.obj_op)(__FILE__, __func__, __LINE__, obj_id, &vol_cb_args, H5P_DEFAULT, H5ES_NONE);
+    if (ret < 0)
+        TEST_ERROR;
+
+    /* Verify that fake object & argument were modified correctly */
+    if (op_val2 != fake_obj)
+        FAIL_PUTS_ERROR("'fake_obj' not updated");
+    if (op_val2 != fake_arg)
+        FAIL_PUTS_ERROR("'fake_arg' not updated");
+
+    /* Named datatypes must be destroyed differently */
+    if (H5VL_SUBCLS_DATATYPE == subcls) {
+        H5T_t *dt;
+
+        /* Destroy fake datatype object */
+        if (NULL == (dt = H5I_remove(obj_id)))
+            TEST_ERROR;
+        if (H5VL_free_object(dt->vol_obj) < 0)
+            TEST_ERROR;
+        dt->vol_obj = NULL;
+        if (H5T_close(dt) < 0)
+            TEST_ERROR;
+    } /* end if */
+    else {
+        /* Destroy fake object */
+        if (NULL == (vol_obj = H5I_remove(obj_id)))
+            TEST_ERROR;
+        if (H5VL_free_object(vol_obj) < 0)
+            TEST_ERROR;
+    } /* end else */
+
+    /* Unregister 2nd registered optional operation */
+    if (H5VLunregister_opt_operation(subcls, op_name) < 0)
+        TEST_ERROR;
+
+    return SUCCEED;
+
+error:
+    return FAIL;
+} /* end exercise_reg_opt_oper() */
+
+/*-------------------------------------------------------------------------
+ * Function:    test_register_opt_operation()
+ *
+ * Purpose:     Tests if we can load, register, and close a simple
+ *              VOL connector.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+test_register_opt_operation(void)
+{
+    hid_t fake_vol_id    = H5I_INVALID_HID;
+    hid_t reg_opt_vol_id = H5I_INVALID_HID;
+    struct {
+        H5VL_subclass_t subcls;
+        const char *    subcls_name;
+        H5I_type_t      id_type;
+        reg_opt_oper_t  reg_opt_op;
+    } test_params[] = {{H5VL_SUBCLS_ATTR, "attr", H5I_ATTR, {.obj_op = H5VLattr_optional_op}},
+                       {H5VL_SUBCLS_DATASET, "dataset", H5I_DATASET, {.obj_op = H5VLdataset_optional_op}},
+                       {H5VL_SUBCLS_DATATYPE, "datatype", H5I_DATATYPE, {.obj_op = H5VLdatatype_optional_op}},
+                       {H5VL_SUBCLS_FILE, "file", H5I_FILE, {.obj_op = H5VLfile_optional_op}},
+                       {H5VL_SUBCLS_GROUP, "group", H5I_GROUP, {.obj_op = H5VLgroup_optional_op}},
+                       {H5VL_SUBCLS_LINK, "link", H5I_GROUP, {.link_op = H5VLlink_optional_op}},
+                       {H5VL_SUBCLS_OBJECT, "object", H5I_GROUP, {.link_op = H5VLobject_optional_op}}};
+    int      op_val = -1;
+    unsigned u;
+    herr_t   ret = SUCCEED;
+
+    TESTING("dynamically registering optional operations");
+
+    /* Register the VOL connectors for testing */
+    if ((fake_vol_id = H5VLregister_connector(&fake_vol_g, H5P_DEFAULT)) < 0)
+        TEST_ERROR;
+    if ((reg_opt_vol_id = H5VLregister_connector(&reg_opt_vol_g, H5P_DEFAULT)) < 0)
+        TEST_ERROR;
+
+    /* Test registering invalid optional VOL subclass operations */
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLregister_opt_operation(H5VL_SUBCLS_NONE, "fail", &op_val);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to register an optional operation for the 'NONE' VOL subclass");
+    if ((-1) != op_val)
+        FAIL_PUTS_ERROR("'op_val' changed during failed operation?");
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLregister_opt_operation(H5VL_SUBCLS_INFO, "fail2", &op_val);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to register an optional operation for the 'INFO' VOL subclass");
+    if ((-1) != op_val)
+        FAIL_PUTS_ERROR("'op_val' changed during failed operation?");
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLregister_opt_operation(H5VL_SUBCLS_WRAP, "fail3", &op_val);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to register an optional operation for the 'WRAP' VOL subclass");
+    if ((-1) != op_val)
+        FAIL_PUTS_ERROR("'op_val' changed during failed operation?");
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLregister_opt_operation(H5VL_SUBCLS_BLOB, "fail4", &op_val);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to register an optional operation for the 'BLOB' VOL subclass");
+    if ((-1) != op_val)
+        FAIL_PUTS_ERROR("'op_val' changed during failed operation?");
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLregister_opt_operation(H5VL_SUBCLS_TOKEN, "fail5", &op_val);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to register an optional operation for the 'TOKEN' VOL subclass");
+    if ((-1) != op_val)
+        FAIL_PUTS_ERROR("'op_val' changed during failed operation?");
+
+    /* Test registering valid optional VOL subclass operation with NULL op_val ptr*/
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLregister_opt_operation(H5VL_SUBCLS_FILE, "fail6", NULL);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to register an optional operation with a NULL 'op_val'");
+
+    /* Try finding a non-existent optional VOL subclass operation */
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLfind_opt_operation(H5VL_SUBCLS_DATASET, "fail", &op_val);
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to find a non-existent optional operation");
+
+    /* Try unregistering a non-existent optional VOL subclass operation */
+    H5E_BEGIN_TRY
+    {
+        ret = H5VLunregister_opt_operation(H5VL_SUBCLS_DATASET, "fail");
+    }
+    H5E_END_TRY;
+    if (FAIL != ret)
+        FAIL_PUTS_ERROR("should not be able to unregister a non-existent optional operation");
+
+    /* Optional operations on requests are supported (but difficult to test further) */
+    if (H5VLregister_opt_operation(H5VL_SUBCLS_REQUEST, "req_op", &op_val) < 0)
+        TEST_ERROR;
+
+    /* Register & test calling optional operations for each valid VOL subclass */
+    /* (Table-driven, with test_params array) */
+    for (u = 0; u < NELMTS(test_params); u++)
+        /* Exercise appropriate callback, for each VOL subclass */
+        if (exercise_reg_opt_oper(fake_vol_id, reg_opt_vol_id, test_params[u].subcls,
+                                  test_params[u].subcls_name, test_params[u].id_type,
+                                  test_params[u].reg_opt_op) < 0)
+            TEST_ERROR;
+
+    /* Unregister the VOL connectors */
+    if (H5VLunregister_connector(fake_vol_id) < 0)
+        TEST_ERROR;
+    if (H5VLunregister_connector(reg_opt_vol_id) < 0)
+        TEST_ERROR;
+
+    PASSED();
+
+    return SUCCEED;
+
+error:
+    H5E_BEGIN_TRY
+    {
+        H5VLunregister_connector(fake_vol_id);
+        H5VLunregister_connector(reg_opt_vol_id);
+    }
+    H5E_END_TRY;
+
+    return FAIL;
+} /* end test_register_opt_operation() */
+
+/*-------------------------------------------------------------------------
+ * Function:    test_async_vol_props()
+ *
+ * Purpose:     Test properties related to asynchronous VOL connector operation
+ *
+ * Note:        Overrides the HDF5_VOL_CONNECTOR environment variable, to
+ *              provide stable testing environment.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+test_async_vol_props(void)
+{
+    hid_t                    fapl_id = H5I_INVALID_HID;
+    hid_t                    vol_id  = H5I_INVALID_HID;
+    H5VL_pass_through_info_t passthru_info;
+    unsigned                 cap_flags    = 0;
+    char *                   conn_env_str = NULL;
+
+    TESTING("Async VOL props");
+
+    /* Retrieve the file access property for testing */
+    fapl_id = h5_fileaccess();
+
+    /* Test 'capability flags' property */
+
+    /* Test query w/NULL for cap_flags parameter */
+    if (H5Pget_vol_cap_flags(fapl_id, NULL) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Override possible environment variable & re-initialize default VOL connector */
+    conn_env_str = HDgetenv(HDF5_VOL_CONNECTOR);
+    if (conn_env_str) {
+        if (NULL == (conn_env_str = HDstrdup(conn_env_str)))
+            TEST_ERROR
+        if (HDunsetenv(HDF5_VOL_CONNECTOR) < 0)
+            TEST_ERROR
+        if (H5VL__reparse_def_vol_conn_variable_test() < 0)
+            TEST_ERROR
+    } /* end if */
+
+    /* Test query w/default VOL, which should indicate no async, since native connector
+     * doesn't support async.
+     */
+    if (H5Pget_vol_cap_flags(fapl_id, &cap_flags) < 0)
+        FAIL_STACK_ERROR;
+    if ((cap_flags & H5VL_CAP_FLAG_ASYNC) > 0)
+        TEST_ERROR
+    if ((cap_flags & H5VL_CAP_FLAG_NATIVE_FILES) == 0)
+        TEST_ERROR
+
+    /* Close FAPL */
+    if (H5Pclose(fapl_id) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Register a fake VOL connector that sets the async capability flag */
+    if ((vol_id = H5VLregister_connector(&fake_async_vol_g, H5P_DEFAULT)) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Set environment variable to use 'fake async' connector & re-init default connector */
+    if (HDsetenv(HDF5_VOL_CONNECTOR, "fake_async", TRUE) < 0)
+        TEST_ERROR
+    if (H5VL__reparse_def_vol_conn_variable_test() < 0)
+        TEST_ERROR
+
+    /* Retrieve the file access property again */
+    fapl_id = h5_fileaccess();
+
+    /* Test query w/fake async VOL, which should succeed */
+    cap_flags = 0;
+    if (H5Pget_vol_cap_flags(fapl_id, &cap_flags) < 0)
+        FAIL_STACK_ERROR;
+    if ((cap_flags & H5VL_CAP_FLAG_ASYNC) == 0)
+        TEST_ERROR
+    if ((cap_flags & H5VL_CAP_FLAG_NATIVE_FILES) > 0)
+        TEST_ERROR
+
+    /* Reset environment variable & re-init default connector */
+    if (HDunsetenv(HDF5_VOL_CONNECTOR) < 0)
+        TEST_ERROR
+    if (H5VL__reparse_def_vol_conn_variable_test() < 0)
+        TEST_ERROR
+
+    /* Close FAPL */
+    if (H5Pclose(fapl_id) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Retrieve the file access property again */
+    fapl_id = h5_fileaccess();
+
+    /* Set the VOL connector for the FAPL to the fake async connector */
+    if (H5Pset_vol(fapl_id, vol_id, NULL) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Test query w/fake async VOL, which should succeed */
+    cap_flags = 0;
+    if (H5Pget_vol_cap_flags(fapl_id, &cap_flags) < 0)
+        FAIL_STACK_ERROR;
+    if ((cap_flags & H5VL_CAP_FLAG_ASYNC) == 0)
+        TEST_ERROR
+    if ((cap_flags & H5VL_CAP_FLAG_NATIVE_FILES) > 0)
+        TEST_ERROR
+
+    /* Stack the [internal] passthrough VOL connector on top of the fake async connector */
+    passthru_info.under_vol_id   = vol_id;
+    passthru_info.under_vol_info = NULL;
+    if (H5Pset_vol(fapl_id, H5VL_PASSTHRU, &passthru_info) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Test query w/passthru -> fake async VOL, which should succeed */
+    cap_flags = 0;
+    if (H5Pget_vol_cap_flags(fapl_id, &cap_flags) < 0)
+        FAIL_STACK_ERROR;
+    if ((cap_flags & H5VL_CAP_FLAG_ASYNC) == 0)
+        TEST_ERROR
+    if ((cap_flags & H5VL_CAP_FLAG_NATIVE_FILES) > 0)
+        TEST_ERROR
+
+    /* Unregister the fake async VOL ID */
+    if (H5VLunregister_connector(vol_id) < 0)
+        TEST_ERROR;
+
+    /* Close FAPL */
+    if (H5Pclose(fapl_id) < 0)
+        FAIL_STACK_ERROR;
+
+    /* Restore environment variable, if there was one */
+    if (conn_env_str) {
+        if (HDsetenv(HDF5_VOL_CONNECTOR, conn_env_str, TRUE) < 0)
+            TEST_ERROR
+        HDfree(conn_env_str);
+
+        if (H5VL__reparse_def_vol_conn_variable_test() < 0)
+            TEST_ERROR
+    } /* end if */
+
+    PASSED();
+
+    return SUCCEED;
+
+error:
+    H5E_BEGIN_TRY
+    {
+        H5Pclose(fapl_id);
+        H5VLunregister_connector(vol_id);
+    }
+    H5E_END_TRY;
+    HDfree(conn_env_str);
+
+    return FAIL;
+} /* end test_async_vol_props() */
+
 /*-------------------------------------------------------------------------
  * Function:    main
  *
@@ -1099,31 +2117,32 @@ error:
 int
 main(void)
 {
-    const char  *env_h5_drvr;   /* File driver value from environment */
-    int nerrors = 0;
+    const char *env_h5_drvr; /* File driver value from environment */
+    int         nerrors = 0;
 
     /* Get the VFD to use */
-    env_h5_drvr = HDgetenv("HDF5_DRIVER");
-    if(env_h5_drvr == NULL)
+    env_h5_drvr = HDgetenv(HDF5_DRIVER);
+    if (env_h5_drvr == NULL)
         env_h5_drvr = "nomatch";
 
     h5_reset();
 
     HDputs("Testing basic Virtual Object Layer (VOL) functionality.");
 
-    nerrors += test_vol_registration() < 0          ? 1 : 0;
-    nerrors += test_native_vol_init() < 0           ? 1 : 0;
+    nerrors += test_vol_registration() < 0 ? 1 : 0;
+    nerrors += test_register_opt_operation() < 0 ? 1 : 0;
+    nerrors += test_native_vol_init() < 0 ? 1 : 0;
     nerrors += test_basic_file_operation(env_h5_drvr) < 0 ? 1 : 0;
-    nerrors += test_basic_group_operation() < 0     ? 1 : 0;
-    nerrors += test_basic_dataset_operation() < 0   ? 1 : 0;
+    nerrors += test_basic_group_operation(env_h5_drvr) < 0 ? 1 : 0;
+    nerrors += test_basic_dataset_operation(env_h5_drvr) < 0 ? 1 : 0;
     nerrors += test_basic_attribute_operation() < 0 ? 1 : 0;
-    nerrors += test_basic_object_operation() < 0    ? 1 : 0;
-    nerrors += test_basic_link_operation() < 0      ? 1 : 0;
-    nerrors += test_basic_datatype_operation() < 0  ? 1 : 0;
+    nerrors += test_basic_object_operation() < 0 ? 1 : 0;
+    nerrors += test_basic_link_operation() < 0 ? 1 : 0;
+    nerrors += test_basic_datatype_operation(env_h5_drvr) < 0 ? 1 : 0;
+    nerrors += test_async_vol_props() < 0 ? 1 : 0;
 
     if (nerrors) {
-        HDprintf("***** %d Virtual Object Layer TEST%s FAILED! *****\n",
-            nerrors, nerrors > 1 ? "S" : "");
+        HDprintf("***** %d Virtual Object Layer TEST%s FAILED! *****\n", nerrors, nerrors > 1 ? "S" : "");
         HDexit(EXIT_FAILURE);
     }
 
@@ -1132,4 +2151,3 @@ main(void)
     HDexit(EXIT_SUCCESS);
 
 } /* end main() */
-