18 files changed, 792 insertions, 58 deletions
diff --git a/Doc/c-api/init_config.rst b/Doc/c-api/init_config.rst
index d6569dd..7497bf2 100644
--- a/Doc/c-api/init_config.rst
+++ b/Doc/c-api/init_config.rst
@@ -1281,6 +1281,15 @@ PyConfig
 
       Default: ``1`` in Python config and ``0`` in isolated config.
 
+   .. c:member:: int use_system_logger
+
+      If non-zero, ``stdout`` and ``stderr`` will be redirected to the system
+      log.
+
+      Only available on macOS 10.12 and later, and on iOS.
+
+      Default: ``0`` (don't use system log).
+
    .. c:member:: int user_site_directory
 
       If non-zero, add the user site directory to :data:`sys.path`.
diff --git a/Doc/using/ios.rst b/Doc/using/ios.rst
index 4d4eb20..aa43f75 100644
--- a/Doc/using/ios.rst
+++ b/Doc/using/ios.rst
@@ -292,10 +292,12 @@ To add Python to an iOS Xcode project:
 10. Add Objective C code to initialize and use a Python interpreter in embedded
     mode. You should ensure that:
 
-   * :c:member:`UTF-8 mode <PyPreConfig.utf8_mode>` is *enabled*;
-   * :c:member:`Buffered stdio <PyConfig.buffered_stdio>` is *disabled*;
-   * :c:member:`Writing bytecode <PyConfig.write_bytecode>` is *disabled*;
-   * :c:member:`Signal handlers <PyConfig.install_signal_handlers>` are *enabled*;
+   * UTF-8 mode (:c:member:`PyPreConfig.utf8_mode`) is *enabled*;
+   * Buffered stdio (:c:member:`PyConfig.buffered_stdio`) is *disabled*;
+   * Writing bytecode (:c:member:`PyConfig.write_bytecode`) is *disabled*;
+   * Signal handlers (:c:member:`PyConfig.install_signal_handlers`) are *enabled*;
+   * System logging (:c:member:`PyConfig.use_system_logger`) is *enabled*
+     (optional, but strongly recommended);
    * ``PYTHONHOME`` for the interpreter is configured to point at the
      ``python`` subfolder of your app's bundle; and
    * The ``PYTHONPATH`` for the interpreter includes:
@@ -324,6 +326,49 @@ modules in your app, some additional steps will be required:
 * If you're using a separate folder for third-party packages, ensure that folder
   is included as part of the ``PYTHONPATH`` configuration in step 10.
 
+Testing a Python package
+------------------------
+
+The CPython source tree contains :source:`a testbed project <iOS/testbed>` that
+is used to run the CPython test suite on the iOS simulator. This testbed can also
+be used as a testbed project for running your Python library's test suite on iOS.
+
+After building or obtaining an iOS XCFramework (See :source:`iOS/README.rst`
+for details), create a clone of the Python iOS testbed project by running:
+
+.. code-block:: bash
+
+    $ python iOS/testbed clone --framework <path/to/Python.xcframework> --app <path/to/module1> --app <path/to/module2> app-testbed
+
+You will need to modify the ``iOS/testbed`` reference to point to that
+directory in the CPython source tree; any folders specified with the ``--app``
+flag will be copied into the cloned testbed project. The resulting testbed will
+be created in the ``app-testbed`` folder. In this example, the ``module1`` and
+``module2`` would be importable modules at runtime. If your project has
+additional dependencies, they can be installed into the
+``app-testbed/iOSTestbed/app_packages`` folder (using ``pip install --target
+app-testbed/iOSTestbed/app_packages`` or similar).
+
+You can then use the ``app-testbed`` folder to run the test suite for your app,
+For example, if ``module1.tests`` was the entry point to your test suite, you
+could run:
+
+.. code-block:: bash
+
+    $ python app-testbed run -- module1.tests
+
+This is the equivalent of running ``python -m module1.tests`` on a desktop
+Python build. Any arguments after the ``--`` will be passed to the testbed as
+if they were arguments to ``python -m`` on a desktop machine.
+
+You can also open the testbed project in Xcode by running:
+
+.. code-block:: bash
+
+    $ open app-testbed/iOSTestbed.xcodeproj
+
+This will allow you to use the full Xcode suite of tools for debugging.
+
 App Store Compliance
 ====================
 
diff --git a/Doc/whatsnew/3.14.rst b/Doc/whatsnew/3.14.rst
index b300e34..b71d31f 100644
--- a/Doc/whatsnew/3.14.rst
+++ b/Doc/whatsnew/3.14.rst
@@ -245,6 +245,13 @@ Other language changes
   making it a :term:`generic type`.
   (Contributed by Brian Schubert in :gh:`126012`.)
 
+* iOS and macOS apps can now be configured to redirect ``stdout`` and
+  ``stderr`` content to the system log. (Contributed by Russell Keith-Magee in
+  :gh:`127592`.)
+
+* The iOS testbed is now able to stream test output while the test is running.
+  The testbed can also be used to run the test suite of projects other than
+  CPython itself. (Contributed by Russell Keith-Magee in :gh:`127592`.)
 
 New modules
 ===========
diff --git a/Include/cpython/initconfig.h b/Include/cpython/initconfig.h
index f69c586..8ef19f6 100644
--- a/Include/cpython/initconfig.h
+++ b/Include/cpython/initconfig.h
@@ -179,6 +179,9 @@ typedef struct PyConfig {
     int use_frozen_modules;
     int safe_path;
     int int_max_str_digits;
+#ifdef __APPLE__
+    int use_system_logger;
+#endif
 
     int cpu_count;
 #ifdef Py_GIL_DISABLED
diff --git a/Lib/_apple_support.py b/Lib/_apple_support.py
new file mode 100644
index 0000000..92febdc
--- /dev/null
+++ b/Lib/_apple_support.py
@@ -0,0 +1,66 @@
+import io
+import sys
+
+
+def init_streams(log_write, stdout_level, stderr_level):
+    # Redirect stdout and stderr to the Apple system log. This method is
+    # invoked by init_apple_streams() (initconfig.c) if config->use_system_logger
+    # is enabled.
+    sys.stdout = SystemLog(log_write, stdout_level, errors=sys.stderr.errors)
+    sys.stderr = SystemLog(log_write, stderr_level, errors=sys.stderr.errors)
+
+
+class SystemLog(io.TextIOWrapper):
+    def __init__(self, log_write, level, **kwargs):
+        kwargs.setdefault("encoding", "UTF-8")
+        kwargs.setdefault("line_buffering", True)
+        super().__init__(LogStream(log_write, level), **kwargs)
+
+    def __repr__(self):
+        return f"<SystemLog (level {self.buffer.level})>"
+
+    def write(self, s):
+        if not isinstance(s, str):
+            raise TypeError(
+                f"write() argument must be str, not {type(s).__name__}")
+
+        # In case `s` is a str subclass that writes itself to stdout or stderr
+        # when we call its methods, convert it to an actual str.
+        s = str.__str__(s)
+
+        # We want to emit one log message per line, so split
+        # the string before sending it to the superclass.
+        for line in s.splitlines(keepends=True):
+            super().write(line)
+
+        return len(s)
+
+
+class LogStream(io.RawIOBase):
+    def __init__(self, log_write, level):
+        self.log_write = log_write
+        self.level = level
+
+    def __repr__(self):
+        return f"<LogStream (level {self.level!r})>"
+
+    def writable(self):
+        return True
+
+    def write(self, b):
+        if type(b) is not bytes:
+            try:
+                b = bytes(memoryview(b))
+            except TypeError:
+                raise TypeError(
+                    f"write() argument must be bytes-like, not {type(b).__name__}"
+                ) from None
+
+        # Writing an empty string to the stream should have no effect.
+        if b:
+            # Encode null bytes using "modified UTF-8" to avoid truncating the
+            # message. This should not affect the return value, as the caller
+            # may be expecting it to match the length of the input.
+            self.log_write(self.level, b.replace(b"\x00", b"\xc0\x80"))
+
+        return len(b)
diff --git a/Lib/test/test_apple.py b/Lib/test/test_apple.py
new file mode 100644
index 0000000..ab5296a
--- /dev/null
+++ b/Lib/test/test_apple.py
@@ -0,0 +1,155 @@
+import unittest
+from _apple_support import SystemLog
+from test.support import is_apple
+from unittest.mock import Mock, call
+
+if not is_apple:
+    raise unittest.SkipTest("Apple-specific")
+
+
+# Test redirection of stdout and stderr to the Apple system log.
+class TestAppleSystemLogOutput(unittest.TestCase):
+    maxDiff = None
+
+    def assert_writes(self, output):
+        self.assertEqual(
+            self.log_write.mock_calls,
+            [
+                call(self.log_level, line)
+                for line in output
+            ]
+        )
+
+        self.log_write.reset_mock()
+
+    def setUp(self):
+        self.log_write = Mock()
+        self.log_level = 42
+        self.log = SystemLog(self.log_write, self.log_level, errors="replace")
+
+    def test_repr(self):
+        self.assertEqual(repr(self.log), "<SystemLog (level 42)>")
+        self.assertEqual(repr(self.log.buffer), "<LogStream (level 42)>")
+
+    def test_log_config(self):
+        self.assertIs(self.log.writable(), True)
+        self.assertIs(self.log.readable(), False)
+
+        self.assertEqual("UTF-8", self.log.encoding)
+        self.assertEqual("replace", self.log.errors)
+
+        self.assertIs(self.log.line_buffering, True)
+        self.assertIs(self.log.write_through, False)
+
+    def test_empty_str(self):
+        self.log.write("")
+        self.log.flush()
+
+        self.assert_writes([])
+
+    def test_simple_str(self):
+        self.log.write("hello world\n")
+
+        self.assert_writes([b"hello world\n"])
+
+    def test_buffered_str(self):
+        self.log.write("h")
+        self.log.write("ello")
+        self.log.write(" ")
+        self.log.write("world\n")
+        self.log.write("goodbye.")
+        self.log.flush()
+
+        self.assert_writes([b"hello world\n", b"goodbye."])
+
+    def test_manual_flush(self):
+        self.log.write("Hello")
+
+        self.assert_writes([])
+
+        self.log.write(" world\nHere for a while...\nGoodbye")
+        self.assert_writes([b"Hello world\n", b"Here for a while...\n"])
+
+        self.log.write(" world\nHello again")
+        self.assert_writes([b"Goodbye world\n"])
+
+        self.log.flush()
+        self.assert_writes([b"Hello again"])
+
+    def test_non_ascii(self):
+        # Spanish
+        self.log.write("ol\u00e9\n")
+        self.assert_writes([b"ol\xc3\xa9\n"])
+
+        # Chinese
+        self.log.write("\u4e2d\u6587\n")
+        self.assert_writes([b"\xe4\xb8\xad\xe6\x96\x87\n"])
+
+        # Printing Non-BMP emoji
+        self.log.write("\U0001f600\n")
+        self.assert_writes([b"\xf0\x9f\x98\x80\n"])
+
+        # Non-encodable surrogates are replaced
+        self.log.write("\ud800\udc00\n")
+        self.assert_writes([b"??\n"])
+
+    def test_modified_null(self):
+        # Null characters are logged using "modified UTF-8".
+        self.log.write("\u0000\n")
+        self.assert_writes([b"\xc0\x80\n"])
+        self.log.write("a\u0000\n")
+        self.assert_writes([b"a\xc0\x80\n"])
+        self.log.write("\u0000b\n")
+        self.assert_writes([b"\xc0\x80b\n"])
+        self.log.write("a\u0000b\n")
+        self.assert_writes([b"a\xc0\x80b\n"])
+
+    def test_nonstandard_str(self):
+        # String subclasses are accepted, but they should be converted
+        # to a standard str without calling any of their methods.
+        class CustomStr(str):
+            def splitlines(self, *args, **kwargs):
+                raise AssertionError()
+
+            def __len__(self):
+                raise AssertionError()
+
+            def __str__(self):
+                raise AssertionError()
+
+        self.log.write(CustomStr("custom\n"))
+        self.assert_writes([b"custom\n"])
+
+    def test_non_str(self):
+        # Non-string classes are not accepted.
+        for obj in [b"", b"hello", None, 42]:
+            with self.subTest(obj=obj):
+                with self.assertRaisesRegex(
+                    TypeError,
+                    fr"write\(\) argument must be str, not "
+                    fr"{type(obj).__name__}"
+                ):
+                    self.log.write(obj)
+
+    def test_byteslike_in_buffer(self):
+        # The underlying buffer *can* accept bytes-like objects
+        self.log.buffer.write(bytearray(b"hello"))
+        self.log.flush()
+
+        self.log.buffer.write(b"")
+        self.log.flush()
+
+        self.log.buffer.write(b"goodbye")
+        self.log.flush()
+
+        self.assert_writes([b"hello", b"goodbye"])
+
+    def test_non_byteslike_in_buffer(self):
+        for obj in ["hello", None, 42]:
+            with self.subTest(obj=obj):
+                with self.assertRaisesRegex(
+                    TypeError,
+                    fr"write\(\) argument must be bytes-like, not "
+                    fr"{type(obj).__name__}"
+                ):
+                    self.log.buffer.write(obj)
diff --git a/Lib/test/test_capi/test_config.py b/Lib/test/test_capi/test_config.py
index 77730ad..a3179ef 100644
--- a/Lib/test/test_capi/test_config.py
+++ b/Lib/test/test_capi/test_config.py
@@ -110,6 +110,10 @@ class CAPITests(unittest.TestCase):
             options.extend((
                 ("_pystats", bool, None),
             ))
+        if support.is_apple:
+            options.extend((
+                ("use_system_logger", bool, None),
+            ))
 
         for name, option_type, sys_attr in options:
             with self.subTest(name=name, option_type=option_type,
diff --git a/Lib/test/test_embed.py b/Lib/test/test_embed.py
index 5c38b28..7110fb8 100644
--- a/Lib/test/test_embed.py
+++ b/Lib/test/test_embed.py
@@ -649,6 +649,8 @@ class InitConfigTests(EmbeddingTestsMixin, unittest.TestCase):
         CONFIG_COMPAT.update({
             'legacy_windows_stdio': False,
         })
+    if support.is_apple:
+        CONFIG_COMPAT['use_system_logger'] = False
 
     CONFIG_PYTHON = dict(CONFIG_COMPAT,
         _config_init=API_PYTHON,
diff --git a/Makefile.pre.in b/Makefile.pre.in
index dd8a3ab..7b66802 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -2146,7 +2146,6 @@ testuniversal: all
 # This must be run *after* a `make install` has completed the build. The
 # `--with-framework-name` argument *cannot* be used when configuring the build.
 XCFOLDER:=iOSTestbed.$(MULTIARCH).$(shell date +%s)
-XCRESULT=$(XCFOLDER)/$(MULTIARCH).xcresult
 .PHONY: testios
 testios:
 	@if test "$(MACHDEP)" != "ios"; then \
@@ -2165,29 +2164,12 @@ testios:
 		echo "Cannot find a finalized iOS Python.framework. Have you run 'make install' to finalize the framework build?"; \
 		exit 1;\
 	fi
-	# Copy the testbed project into the build folder
-	cp -r $(srcdir)/iOS/testbed $(XCFOLDER)
-	# Copy the framework from the install location to the testbed project.
-	cp -r $(PYTHONFRAMEWORKPREFIX)/* $(XCFOLDER)/Python.xcframework/ios-arm64_x86_64-simulator
-
-	# Run the test suite for the Xcode project, targeting the iOS simulator.
-	# If the suite fails, touch a file in the test folder as a marker
-	if ! xcodebuild test -project $(XCFOLDER)/iOSTestbed.xcodeproj -scheme "iOSTestbed" -destination "platform=iOS Simulator,name=iPhone SE (3rd Generation)" -resultBundlePath $(XCRESULT) -derivedDataPath $(XCFOLDER)/DerivedData ; then \
-	 	touch $(XCFOLDER)/failed; \
-	fi
 
-	# Regardless of success or failure, extract and print the test output
-	xcrun xcresulttool get --path $(XCRESULT) \
-		--id $$( \
-			xcrun xcresulttool get --path $(XCRESULT) --format json | \
-			$(PYTHON_FOR_BUILD) -c "import sys, json; result = json.load(sys.stdin); print(result['actions']['_values'][0]['actionResult']['logRef']['id']['_value'])" \
-		) \
-		--format json | \
-		$(PYTHON_FOR_BUILD) -c "import sys, json; result = json.load(sys.stdin); print(result['subsections']['_values'][1]['subsections']['_values'][0]['emittedOutput']['_value'])"
+	# Clone the testbed project into the XCFOLDER
+	$(PYTHON_FOR_BUILD) $(srcdir)/iOS/testbed clone --framework $(PYTHONFRAMEWORKPREFIX) "$(XCFOLDER)"
 
-	@if test -e $(XCFOLDER)/failed ; then \
-		exit 1; \
-	fi
+	# Run the testbed project
+	$(PYTHON_FOR_BUILD) "$(XCFOLDER)" run -- test -uall --single-process --rerun -W
 
 # Like test, but using --slow-ci which enables all test resources and use
 # longer timeout. Run an optional pybuildbot.identify script to include
diff --git a/Misc/NEWS.d/next/Library/2024-12-04-15-04-12.gh-issue-126821.lKCLVV.rst b/Misc/NEWS.d/next/Library/2024-12-04-15-04-12.gh-issue-126821.lKCLVV.rst
new file mode 100644
index 0000000..677acf5
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2024-12-04-15-04-12.gh-issue-126821.lKCLVV.rst
@@ -0,0 +1,2 @@
+macOS and iOS apps can now choose to redirect stdout and stderr to the
+system log during interpreter configuration.
diff --git a/Misc/NEWS.d/next/Tests/2024-12-04-15-03-24.gh-issue-126925.uxAMK-.rst b/Misc/NEWS.d/next/Tests/2024-12-04-15-03-24.gh-issue-126925.uxAMK-.rst
new file mode 100644
index 0000000..fb307c7
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2024-12-04-15-03-24.gh-issue-126925.uxAMK-.rst
@@ -0,0 +1,2 @@
+iOS test results are now streamed during test execution, and the deprecated
+xcresulttool is no longer used.
diff --git a/Python/initconfig.c b/Python/initconfig.c
index 438f8a5..7851b86 100644
--- a/Python/initconfig.c
+++ b/Python/initconfig.c
@@ -168,6 +168,9 @@ static const PyConfigSpec PYCONFIG_SPEC[] = {
     SPEC(tracemalloc, UINT, READ_ONLY, NO_SYS),
     SPEC(use_frozen_modules, BOOL, READ_ONLY, NO_SYS),
     SPEC(use_hash_seed, BOOL, READ_ONLY, NO_SYS),
+#ifdef __APPLE__
+    SPEC(use_system_logger, BOOL, PUBLIC, NO_SYS),
+#endif
     SPEC(user_site_directory, BOOL, READ_ONLY, NO_SYS),  // sys.flags.no_user_site
     SPEC(warn_default_encoding, BOOL, READ_ONLY, NO_SYS),
 
@@ -884,6 +887,9 @@ config_check_consistency(const PyConfig *config)
     assert(config->cpu_count != 0);
     // config->use_frozen_modules is initialized later
     // by _PyConfig_InitImportConfig().
+#ifdef __APPLE__
+    assert(config->use_system_logger >= 0);
+#endif
 #ifdef Py_STATS
     assert(config->_pystats >= 0);
 #endif
@@ -986,6 +992,9 @@ _PyConfig_InitCompatConfig(PyConfig *config)
     config->_is_python_build = 0;
     config->code_debug_ranges = 1;
     config->cpu_count = -1;
+#ifdef __APPLE__
+    config->use_system_logger = 0;
+#endif
 #ifdef Py_GIL_DISABLED
     config->enable_gil = _PyConfig_GIL_DEFAULT;
     config->tlbc_enabled = 1;
@@ -1015,6 +1024,9 @@ config_init_defaults(PyConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_stdio = 0;
 #endif
+#ifdef __APPLE__
+    config->use_system_logger = 0;
+#endif
 }
 
 
@@ -1049,6 +1061,9 @@ PyConfig_InitIsolatedConfig(PyConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_stdio = 0;
 #endif
+#ifdef __APPLE__
+    config->use_system_logger = 0;
+#endif
 }
 
 
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index ceb30e9..0641812 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -45,7 +45,9 @@
 #endif
 
 #if defined(__APPLE__)
+#  include <AvailabilityMacros.h>
 #  include <mach-o/loader.h>
+#  include <os/log.h>
 #endif
 
 #ifdef HAVE_SIGNAL_H
@@ -75,6 +77,9 @@ static PyStatus init_sys_streams(PyThreadState *tstate);
 #ifdef __ANDROID__
 static PyStatus init_android_streams(PyThreadState *tstate);
 #endif
+#if defined(__APPLE__)
+static PyStatus init_apple_streams(PyThreadState *tstate);
+#endif
 static void wait_for_thread_shutdown(PyThreadState *tstate);
 static void finalize_subinterpreters(void);
 static void call_ll_exitfuncs(_PyRuntimeState *runtime);
@@ -1257,6 +1262,14 @@ init_interp_main(PyThreadState *tstate)
         return status;
     }
 #endif
+#if defined(__APPLE__)
+    if (config->use_system_logger) {
+        status = init_apple_streams(tstate);
+        if (_PyStatus_EXCEPTION(status)) {
+            return status;
+        }
+    }
+#endif
 
 #ifdef Py_DEBUG
     run_presite(tstate);
@@ -2933,6 +2946,75 @@ done:
 
 #endif  // __ANDROID__
 
+#if defined(__APPLE__)
+
+static PyObject *
+apple_log_write_impl(PyObject *self, PyObject *args)
+{
+    int logtype = 0;
+    const char *text = NULL;
+    if (!PyArg_ParseTuple(args, "iy", &logtype, &text)) {
+        return NULL;
+    }
+
+    // Call the underlying Apple logging API. The os_log unified logging APIs
+    // were introduced in macOS 10.12, iOS 10.0, tvOS 10.0, and watchOS 3.0;
+    // this call is a no-op on older versions.
+    #if TARGET_OS_IPHONE || (TARGET_OS_OSX && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12)
+    // Pass the user-provided text through explicit %s formatting
+    // to avoid % literals being interpreted as a formatting directive.
+    os_log_with_type(OS_LOG_DEFAULT, logtype, "%s", text);
+    #endif
+    Py_RETURN_NONE;
+}
+
+
+static PyMethodDef apple_log_write_method = {
+    "apple_log_write", apple_log_write_impl, METH_VARARGS
+};
+
+
+static PyStatus
+init_apple_streams(PyThreadState *tstate)
+{
+    PyStatus status = _PyStatus_OK();
+    PyObject *_apple_support = NULL;
+    PyObject *apple_log_write = NULL;
+    PyObject *result = NULL;
+
+    _apple_support = PyImport_ImportModule("_apple_support");
+    if (_apple_support == NULL) {
+        goto error;
+    }
+
+    apple_log_write = PyCFunction_New(&apple_log_write_method, NULL);
+    if (apple_log_write == NULL) {
+        goto error;
+    }
+
+    // Initialize the logging streams, sending stdout -> Default; stderr -> Error
+    result = PyObject_CallMethod(
+        _apple_support, "init_streams", "Oii",
+        apple_log_write, OS_LOG_TYPE_DEFAULT, OS_LOG_TYPE_ERROR);
+    if (result == NULL) {
+        goto error;
+    }
+
+    goto done;
+
+error:
+    _PyErr_Print(tstate);
+    status = _PyStatus_ERR("failed to initialize Apple log streams");
+
+done:
+    Py_XDECREF(result);
+    Py_XDECREF(apple_log_write);
+    Py_XDECREF(_apple_support);
+    return status;
+}
+
+#endif  // __APPLE__
+
 
 static void
 _Py_FatalError_DumpTracebacks(int fd, PyInterpreterState *interp,
diff --git a/Python/stdlib_module_names.h b/Python/stdlib_module_names.h
index c8cdb93..584b050 100644
--- a/Python/stdlib_module_names.h
+++ b/Python/stdlib_module_names.h
@@ -6,6 +6,7 @@ static const char* _Py_stdlib_module_names[] = {
 "_abc",
 "_aix_support",
 "_android_support",
+"_apple_support",
 "_ast",
 "_asyncio",
 "_bisect",
diff --git a/iOS/README.rst b/iOS/README.rst
index e33455e..9cea98c 100644
--- a/iOS/README.rst
+++ b/iOS/README.rst
@@ -285,52 +285,42 @@ This will:
 * Install the Python iOS framework into the copy of the testbed project; and
 * Run the test suite on an "iPhone SE (3rd generation)" simulator.
 
-While the test suite is running, Xcode does not display any console output.
-After showing some Xcode build commands, the console output will print ``Testing
-started``, and then appear to stop. It will remain in this state until the test
-suite completes. On a 2022 M1 MacBook Pro, the test suite takes approximately 12
-minutes to run; a couple of extra minutes is required to boot and prepare the
-iOS simulator.
-
 On success, the test suite will exit and report successful completion of the
-test suite. No output of the Python test suite will be displayed.
-
-On failure, the output of the Python test suite *will* be displayed. This will
-show the details of the tests that failed.
+test suite. On a 2022 M1 MacBook Pro, the test suite takes approximately 12
+minutes to run; a couple of extra minutes is required to compile the testbed
+project, and then boot and prepare the iOS simulator.
 
 Debugging test failures
 -----------------------
 
-The easiest way to diagnose a single test failure is to open the testbed project
-in Xcode and run the tests from there using the "Product > Test" menu item.
-
-To test in Xcode, you must ensure the testbed project has a copy of a compiled
-framework. If you've configured your build with the default install location of
-``iOS/Frameworks``, you can copy from that location into the test project. To
-test on an ARM64 simulator, run::
-
-    $ rm -rf iOS/testbed/Python.xcframework/ios-arm64_x86_64-simulator/*
-    $ cp -r iOS/Frameworks/arm64-iphonesimulator/* iOS/testbed/Python.xcframework/ios-arm64_x86_64-simulator
+Running ``make test`` generates a standalone version of the ``iOS/testbed``
+project, and runs the full test suite. It does this using ``iOS/testbed``
+itself - the folder is an executable module that can be used to create and run
+a clone of the testbed project.
 
-To test on an x86-64 simulator, run::
+You can generate your own standalone testbed instance by running::
 
-    $ rm -rf iOS/testbed/Python.xcframework/ios-arm64_x86_64-simulator/*
-    $ cp -r iOS/Frameworks/x86_64-iphonesimulator/* iOS/testbed/Python.xcframework/ios-arm64_x86_64-simulator
+    $ python iOS/testbed clone --framework iOS/Frameworks/arm64-iphonesimulator my-testbed
 
-To test on a physical device::
+This invocation assumes that ``iOS/Frameworks/arm64-iphonesimulator`` is the
+path to the iOS simulator framework for your platform (ARM64 in this case);
+``my-testbed`` is the name of the folder for the new testbed clone.
 
-    $ rm -rf iOS/testbed/Python.xcframework/ios-arm64/*
-    $ cp -r iOS/Frameworks/arm64-iphoneos/* iOS/testbed/Python.xcframework/ios-arm64
+You can then use the ``my-testbed`` folder to run the Python test suite,
+passing in any command line arguments you may require. For example, if you're
+trying to diagnose a failure in the ``os`` module, you might run::
 
-Alternatively, you can configure your build to install directly into the
-testbed project. For a simulator, use::
+    $ python my-testbed run -- test -W test_os
 
-    --enable-framework=$(pwd)/iOS/testbed/Python.xcframework/ios-arm64_x86_64-simulator
+This is the equivalent of running ``python -m test -W test_os`` on a desktop
+Python build. Any arguments after the ``--`` will be passed to testbed as if
+they were arguments to ``python -m`` on a desktop machine.
 
-For a physical device, use::
+You can also open the testbed project in Xcode by running::
 
-    --enable-framework=$(pwd)/iOS/testbed/Python.xcframework/ios-arm64
+    $ open my-testbed/iOSTestbed.xcodeproj
 
+This will allow you to use the full Xcode suite of tools for debugging.
 
 Testing on an iOS device
 ^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/iOS/testbed/__main__.py b/iOS/testbed/__main__.py
new file mode 100644
index 0000000..22570ee
--- /dev/null
+++ b/iOS/testbed/__main__.py
@@ -0,0 +1,365 @@
+import argparse
+import asyncio
+import json
+import plistlib
+import shutil
+import subprocess
+import sys
+from contextlib import asynccontextmanager
+from datetime import datetime
+from pathlib import Path
+
+
+DECODE_ARGS = ("UTF-8", "backslashreplace")
+
+
+# Work around a bug involving sys.exit and TaskGroups
+# (https://github.com/python/cpython/issues/101515).
+def exit(*args):
+    raise MySystemExit(*args)
+
+
+class MySystemExit(Exception):
+    pass
+
+
+# All subprocesses are executed through this context manager so that no matter
+# what happens, they can always be cancelled from another task, and they will
+# always be cleaned up on exit.
+@asynccontextmanager
+async def async_process(*args, **kwargs):
+    process = await asyncio.create_subprocess_exec(*args, **kwargs)
+    try:
+        yield process
+    finally:
+        if process.returncode is None:
+            # Allow a reasonably long time for Xcode to clean itself up,
+            # because we don't want stale emulators left behind.
+            timeout = 10
+            process.terminate()
+            try:
+                await asyncio.wait_for(process.wait(), timeout)
+            except TimeoutError:
+                print(
+                    f"Command {args} did not terminate after {timeout} seconds "
+                    f" - sending SIGKILL"
+                )
+                process.kill()
+
+                # Even after killing the process we must still wait for it,
+                # otherwise we'll get the warning "Exception ignored in __del__".
+                await asyncio.wait_for(process.wait(), timeout=1)
+
+
+async def async_check_output(*args, **kwargs):
+    async with async_process(
+        *args, stdout=subprocess.PIPE, stderr=subprocess.PIPE, **kwargs
+    ) as process:
+        stdout, stderr = await process.communicate()
+        if process.returncode == 0:
+            return stdout.decode(*DECODE_ARGS)
+        else:
+            raise subprocess.CalledProcessError(
+                process.returncode,
+                args,
+                stdout.decode(*DECODE_ARGS),
+                stderr.decode(*DECODE_ARGS),
+            )
+
+
+# Return a list of UDIDs associated with booted simulators
+async def list_devices():
+    # List the testing simulators, in JSON format
+    raw_json = await async_check_output(
+        "xcrun", "simctl", "--set", "testing", "list", "-j"
+    )
+    json_data = json.loads(raw_json)
+
+    # Filter out the booted iOS simulators
+    return [
+        simulator["udid"]
+        for runtime, simulators in json_data["devices"].items()
+        for simulator in simulators
+        if runtime.split(".")[-1].startswith("iOS") and simulator["state"] == "Booted"
+    ]
+
+
+async def find_device(initial_devices):
+    while True:
+        new_devices = set(await list_devices()).difference(initial_devices)
+        if len(new_devices) == 0:
+            await asyncio.sleep(1)
+        elif len(new_devices) == 1:
+            udid = new_devices.pop()
+            print(f"{datetime.now():%Y-%m-%d %H:%M:%S}: New test simulator detected")
+            print(f"UDID: {udid}")
+            return udid
+        else:
+            exit(f"Found more than one new device: {new_devices}")
+
+
+async def log_stream_task(initial_devices):
+    # Wait up to 5 minutes for the build to complete and the simulator to boot.
+    udid = await asyncio.wait_for(find_device(initial_devices), 5 * 60)
+
+    # Stream the iOS device's logs, filtering out messages that come from the
+    # XCTest test suite (catching NSLog messages from the test method), or
+    # Python itself (catching stdout/stderr content routed to the system log
+    # with config->use_system_logger).
+    args = [
+        "xcrun",
+        "simctl",
+        "--set",
+        "testing",
+        "spawn",
+        udid,
+        "log",
+        "stream",
+        "--style",
+        "compact",
+        "--predicate",
+        (
+            'senderImagePath ENDSWITH "/iOSTestbedTests.xctest/iOSTestbedTests"'
+            ' OR senderImagePath ENDSWITH "/Python.framework/Python"'
+        ),
+    ]
+
+    async with async_process(
+        *args,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+    ) as process:
+        suppress_dupes = False
+        while line := (await process.stdout.readline()).decode(*DECODE_ARGS):
+            # The iOS log streamer can sometimes lag; when it does, it outputs
+            # a warning about messages being dropped... often multiple times.
+            # Only print the first of these duplicated warnings.
+            if line.startswith("=== Messages dropped "):
+                if not suppress_dupes:
+                    suppress_dupes = True
+                    sys.stdout.write(line)
+            else:
+                suppress_dupes = False
+                sys.stdout.write(line)
+
+
+async def xcode_test(location, simulator):
+    # Run the test suite on the named simulator
+    args = [
+        "xcodebuild",
+        "test",
+        "-project",
+        str(location / "iOSTestbed.xcodeproj"),
+        "-scheme",
+        "iOSTestbed",
+        "-destination",
+        f"platform=iOS Simulator,name={simulator}",
+        "-resultBundlePath",
+        str(location / f"{datetime.now():%Y%m%d-%H%M%S}.xcresult"),
+        "-derivedDataPath",
+        str(location / "DerivedData"),
+    ]
+    async with async_process(
+        *args,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+    ) as process:
+        while line := (await process.stdout.readline()).decode(*DECODE_ARGS):
+            sys.stdout.write(line)
+
+        status = await asyncio.wait_for(process.wait(), timeout=1)
+        exit(status)
+
+
+def clone_testbed(
+    source: Path,
+    target: Path,
+    framework: Path,
+    apps: list[Path],
+) -> None:
+    if target.exists():
+        print(f"{target} already exists; aborting without creating project.")
+        sys.exit(10)
+
+    if framework is None:
+        if not (source / "Python.xcframework/ios-arm64_x86_64-simulator/bin").is_dir():
+            print(
+                f"The testbed being cloned ({source}) does not contain "
+                f"a simulator framework. Re-run with --framework"
+            )
+            sys.exit(11)
+    else:
+        if not framework.is_dir():
+            print(f"{framework} does not exist.")
+            sys.exit(12)
+        elif not (
+            framework.suffix == ".xcframework"
+            or (framework / "Python.framework").is_dir()
+        ):
+            print(
+                f"{framework} is not an XCframework, "
+                f"or a simulator slice of a framework build."
+            )
+            sys.exit(13)
+
+    print("Cloning testbed project...")
+    shutil.copytree(source, target)
+
+    if framework is not None:
+        if framework.suffix == ".xcframework":
+            print("Installing XCFramework...")
+            xc_framework_path = target / "Python.xcframework"
+            shutil.rmtree(xc_framework_path)
+            shutil.copytree(framework, xc_framework_path)
+        else:
+            print("Installing simulator Framework...")
+            sim_framework_path = (
+                target / "Python.xcframework" / "ios-arm64_x86_64-simulator"
+            )
+            shutil.rmtree(sim_framework_path)
+            shutil.copytree(framework, sim_framework_path)
+    else:
+        print("Using pre-existing iOS framework.")
+
+    for app_src in apps:
+        print(f"Installing app {app_src.name!r}...")
+        app_target = target / f"iOSTestbed/app/{app_src.name}"
+        if app_target.is_dir():
+            shutil.rmtree(app_target)
+        shutil.copytree(app_src, app_target)
+
+    print(f"Testbed project created in {target}")
+
+
+def update_plist(testbed_path, args):
+    # Add the test runner arguments to the testbed's Info.plist file.
+    info_plist = testbed_path / "iOSTestbed" / "iOSTestbed-Info.plist"
+    with info_plist.open("rb") as f:
+        info = plistlib.load(f)
+
+    info["TestArgs"] = args
+
+    with info_plist.open("wb") as f:
+        plistlib.dump(info, f)
+
+
+async def run_testbed(simulator: str, args: list[str]):
+    location = Path(__file__).parent
+    print("Updating plist...")
+    update_plist(location, args)
+
+    # Get the list of devices that are booted at the start of the test run.
+    # The simulator started by the test suite will be detected as the new
+    # entry that appears on the device list.
+    initial_devices = await list_devices()
+
+    try:
+        async with asyncio.TaskGroup() as tg:
+            tg.create_task(log_stream_task(initial_devices))
+            tg.create_task(xcode_test(location, simulator))
+    except* MySystemExit as e:
+        raise SystemExit(*e.exceptions[0].args) from None
+    except* subprocess.CalledProcessError as e:
+        # Extract it from the ExceptionGroup so it can be handled by `main`.
+        raise e.exceptions[0]
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description=(
+            "Manages the process of testing a Python project in the iOS simulator."
+        ),
+    )
+
+    subcommands = parser.add_subparsers(dest="subcommand")
+
+    clone = subcommands.add_parser(
+        "clone",
+        description=(
+            "Clone the testbed project, copying in an iOS Python framework and"
+            "any specified application code."
+        ),
+        help="Clone a testbed project to a new location.",
+    )
+    clone.add_argument(
+        "--framework",
+        help=(
+            "The location of the XCFramework (or simulator-only slice of an "
+            "XCFramework) to use when running the testbed"
+        ),
+    )
+    clone.add_argument(
+        "--app",
+        dest="apps",
+        action="append",
+        default=[],
+        help="The location of any code to include in the testbed project",
+    )
+    clone.add_argument(
+        "location",
+        help="The path where the testbed will be cloned.",
+    )
+
+    run = subcommands.add_parser(
+        "run",
+        usage="%(prog)s [-h] [--simulator SIMULATOR] -- <test arg> [<test arg> ...]",
+        description=(
+            "Run a testbed project. The arguments provided after `--` will be "
+            "passed to the running iOS process as if they were arguments to "
+            "`python -m`."
+        ),
+        help="Run a testbed project",
+    )
+    run.add_argument(
+        "--simulator",
+        default="iPhone SE (3rd Generation)",
+        help="The name of the simulator to use (default: 'iPhone SE (3rd Generation)')",
+    )
+
+    try:
+        pos = sys.argv.index("--")
+        testbed_args = sys.argv[1:pos]
+        test_args = sys.argv[pos + 1 :]
+    except ValueError:
+        testbed_args = sys.argv[1:]
+        test_args = []
+
+    context = parser.parse_args(testbed_args)
+
+    if context.subcommand == "clone":
+        clone_testbed(
+            source=Path(__file__).parent,
+            target=Path(context.location),
+            framework=Path(context.framework) if context.framework else None,
+            apps=[Path(app) for app in context.apps],
+        )
+    elif context.subcommand == "run":
+        if test_args:
+            if not (
+                Path(__file__).parent / "Python.xcframework/ios-arm64_x86_64-simulator/bin"
+            ).is_dir():
+                print(
+                    f"Testbed does not contain a compiled iOS framework. Use "
+                    f"`python {sys.argv[0]} clone ...` to create a runnable "
+                    f"clone of this testbed."
+                )
+                sys.exit(20)
+
+            asyncio.run(
+                run_testbed(
+                    simulator=context.simulator,
+                    args=test_args,
+                )
+            )
+        else:
+            print(f"Must specify test arguments (e.g., {sys.argv[0]} run -- test)")
+            print()
+            parser.print_help(sys.stderr)
+            sys.exit(21)
+    else:
+        parser.print_help(sys.stderr)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/iOS/testbed/iOSTestbed.xcodeproj/project.pbxproj b/iOS/testbed/iOSTestbed.xcodeproj/project.pbxproj
index 6819ac0..c7d6390 100644
--- a/iOS/testbed/iOSTestbed.xcodeproj/project.pbxproj
+++ b/iOS/testbed/iOSTestbed.xcodeproj/project.pbxproj
@@ -263,6 +263,7 @@
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
 			shellScript = "set -e\n\nmkdir -p \"$CODESIGNING_FOLDER_PATH/python/lib\"\nif [ \"$EFFECTIVE_PLATFORM_NAME\" = \"-iphonesimulator\" ]; then\n    echo \"Installing Python modules for iOS Simulator\"\n    rsync -au --delete \"$PROJECT_DIR/Python.xcframework/ios-arm64_x86_64-simulator/lib/\" \"$CODESIGNING_FOLDER_PATH/python/lib/\" \nelse\n    echo \"Installing Python modules for iOS Device\"\n    rsync -au --delete \"$PROJECT_DIR/Python.xcframework/ios-arm64/lib/\" \"$CODESIGNING_FOLDER_PATH/python/lib/\" \nfi\n";
+			showEnvVarsInLog = 0;
 		};
 		607A66562B0F06200010BFC8 /* Prepare Python Binary Modules */ = {
 			isa = PBXShellScriptBuildPhase;
@@ -282,6 +283,7 @@
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
 			shellScript = "set -e\n\ninstall_dylib () {\n    INSTALL_BASE=$1\n    FULL_EXT=$2\n\n    # The name of the extension file\n    EXT=$(basename \"$FULL_EXT\")\n    # The location of the extension file, relative to the bundle\n    RELATIVE_EXT=${FULL_EXT#$CODESIGNING_FOLDER_PATH/} \n    # The path to the extension file, relative to the install base\n    PYTHON_EXT=${RELATIVE_EXT/$INSTALL_BASE/}\n    # The full dotted name of the extension module, constructed from the file path.\n    FULL_MODULE_NAME=$(echo $PYTHON_EXT | cut -d \".\" -f 1 | tr \"/\" \".\"); \n    # A bundle identifier; not actually used, but required by Xcode framework packaging\n    FRAMEWORK_BUNDLE_ID=$(echo $PRODUCT_BUNDLE_IDENTIFIER.$FULL_MODULE_NAME | tr \"_\" \"-\")\n    # The name of the framework folder.\n    FRAMEWORK_FOLDER=\"Frameworks/$FULL_MODULE_NAME.framework\"\n\n    # If the framework folder doesn't exist, create it.\n    if [ ! -d \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER\" ]; then\n        echo \"Creating framework for $RELATIVE_EXT\" \n        mkdir -p \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER\"\n        cp \"$CODESIGNING_FOLDER_PATH/dylib-Info-template.plist\" \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist\"\n        plutil -replace CFBundleExecutable -string \"$FULL_MODULE_NAME\" \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist\"\n        plutil -replace CFBundleIdentifier -string \"$FRAMEWORK_BUNDLE_ID\" \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/Info.plist\"\n    fi\n    \n    echo \"Installing binary for $FRAMEWORK_FOLDER/$FULL_MODULE_NAME\" \n    mv \"$FULL_EXT\" \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/$FULL_MODULE_NAME\"\n    # Create a placeholder .fwork file where the .so was\n    echo \"$FRAMEWORK_FOLDER/$FULL_MODULE_NAME\" > ${FULL_EXT%.so}.fwork\n    # Create a back reference to the .so file location in the framework\n    echo \"${RELATIVE_EXT%.so}.fwork\" > \"$CODESIGNING_FOLDER_PATH/$FRAMEWORK_FOLDER/$FULL_MODULE_NAME.origin\"             \n}\n\nPYTHON_VER=$(ls -1 \"$CODESIGNING_FOLDER_PATH/python/lib\")\necho \"Install Python $PYTHON_VER standard library extension modules...\"\nfind \"$CODESIGNING_FOLDER_PATH/python/lib/$PYTHON_VER/lib-dynload\" -name \"*.so\" | while read FULL_EXT; do\n    install_dylib python/lib/$PYTHON_VER/lib-dynload/ \"$FULL_EXT\"\ndone\necho \"Install app package extension modules...\"\nfind \"$CODESIGNING_FOLDER_PATH/app_packages\" -name \"*.so\" | while read FULL_EXT; do\n    install_dylib app_packages/ \"$FULL_EXT\"\ndone\necho \"Install app extension modules...\"\nfind \"$CODESIGNING_FOLDER_PATH/app\" -name \"*.so\" | while read FULL_EXT; do\n    install_dylib app/ \"$FULL_EXT\"\ndone\n\n# Clean up dylib template \nrm -f \"$CODESIGNING_FOLDER_PATH/dylib-Info-template.plist\"\necho \"Signing frameworks as $EXPANDED_CODE_SIGN_IDENTITY_NAME ($EXPANDED_CODE_SIGN_IDENTITY)...\"\nfind \"$CODESIGNING_FOLDER_PATH/Frameworks\" -name \"*.framework\" -exec /usr/bin/codesign --force --sign \"$EXPANDED_CODE_SIGN_IDENTITY\" ${OTHER_CODE_SIGN_FLAGS:-} -o runtime --timestamp=none --preserve-metadata=identifier,entitlements,flags --generate-entitlement-der \"{}\" \\; \n";
+			showEnvVarsInLog = 0;
 		};
 /* End PBXShellScriptBuildPhase section */
 
diff --git a/iOS/testbed/iOSTestbedTests/iOSTestbedTests.m b/iOS/testbed/iOSTestbedTests/iOSTestbedTests.m
index db00d43..ac78456 100644
--- a/iOS/testbed/iOSTestbedTests/iOSTestbedTests.m
+++ b/iOS/testbed/iOSTestbedTests/iOSTestbedTests.m
@@ -50,6 +50,8 @@
     // Enforce UTF-8 encoding for stderr, stdout, file-system encoding and locale.
     // See https://docs.python.org/3/library/os.html#python-utf-8-mode.
     preconfig.utf8_mode = 1;
+    // Use the system logger for stdout/err
+    config.use_system_logger = 1;
     // Don't buffer stdio. We want output to appears in the log immediately
     config.buffered_stdio = 0;
     // Don't write bytecode; we can't modify the app bundle