gh-127845: Minor improvements to iOS test runner script (#127846)

Uses symlinks to install iOS framework into testbed clone, adds a verbose mode
to the iOS runner to hide most Xcode output, adds another mechanism to disable
terminal colors, and ensures that stdout is flushed after every write.

Makefile.pre.in

@@ -2169,7 +2169,7 @@ testios:
 	$(PYTHON_FOR_BUILD) $(srcdir)/iOS/testbed clone --framework $(PYTHONFRAMEWORKPREFIX) "$(XCFOLDER)"
 
 	# Run the testbed project
-	$(PYTHON_FOR_BUILD) "$(XCFOLDER)" run -- test -uall --single-process --rerun -W
+	$(PYTHON_FOR_BUILD) "$(XCFOLDER)" run --verbose -- 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

iOS/testbed/__main__.py

@@ -141,10 +141,12 @@ async def log_stream_task(initial_devices):
             else:
                 suppress_dupes = False
                 sys.stdout.write(line)
+            sys.stdout.flush()
 
 
-async def xcode_test(location, simulator):
+async def xcode_test(location, simulator, verbose):
     # Run the test suite on the named simulator
+    print("Starting xcodebuild...")
     args = [
         "xcodebuild",
         "test",
@@ -159,13 +161,17 @@ async def xcode_test(location, simulator):
         "-derivedDataPath",
         str(location / "DerivedData"),
     ]
+    if not verbose:
+        args += ["-quiet"]
+
     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)
+            sys.stdout.flush()
 
         status = await asyncio.wait_for(process.wait(), timeout=1)
         exit(status)
@@ -182,7 +188,9 @@ def clone_testbed(
         sys.exit(10)
 
     if framework is None:
-        if not (source / "Python.xcframework/ios-arm64_x86_64-simulator/bin").is_dir():
+        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"
@@ -202,33 +210,48 @@ def clone_testbed(
             )
             sys.exit(13)
 
-    print("Cloning testbed project...")
-    shutil.copytree(source, target)
+    print("Cloning testbed project:")
+    print(f"  Cloning {source}...", end="", flush=True)
+    shutil.copytree(source, target, symlinks=True)
+    print(" done")
 
     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)
+            print("  Installing XCFramework...", end="", flush=True)
+            xc_framework_path = (target / "Python.xcframework").resolve()
+            if xc_framework_path.is_dir():
+                shutil.rmtree(xc_framework_path)
+            else:
+                xc_framework_path.unlink()
+            xc_framework_path.symlink_to(
+                framework.relative_to(xc_framework_path.parent, walk_up=True)
+            )
+            print(" done")
         else:
-            print("Installing simulator Framework...")
+            print("  Installing simulator framework...", end="", flush=True)
             sim_framework_path = (
                 target / "Python.xcframework" / "ios-arm64_x86_64-simulator"
+            ).resolve()
+            if sim_framework_path.is_dir():
+                shutil.rmtree(sim_framework_path)
+            else:
+                sim_framework_path.unlink()
+            sim_framework_path.symlink_to(
+                framework.relative_to(sim_framework_path.parent, walk_up=True)
             )
-            shutil.rmtree(sim_framework_path)
-            shutil.copytree(framework, sim_framework_path)
+            print(" done")
     else:
-        print("Using pre-existing iOS framework.")
+        print("  Using pre-existing iOS framework.")
 
     for app_src in apps:
-        print(f"Installing app {app_src.name!r}...")
+        print(f"  Installing app {app_src.name!r}...", end="", flush=True)
         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(" done")
 
-    print(f"Testbed project created in {target}")
+    print(f"Successfully cloned testbed: {target.resolve()}")
 
 
 def update_plist(testbed_path, args):
@@ -243,10 +266,11 @@ def update_plist(testbed_path, args):
         plistlib.dump(info, f)
 
 
-async def run_testbed(simulator: str, args: list[str]):
+async def run_testbed(simulator: str, args: list[str], verbose: bool=False):
     location = Path(__file__).parent
-    print("Updating plist...")
+    print("Updating plist...", end="", flush=True)
     update_plist(location, args)
+    print(" done.")
 
     # 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
@@ -256,7 +280,7 @@ async def run_testbed(simulator: str, args: list[str]):
     try:
         async with asyncio.TaskGroup() as tg:
             tg.create_task(log_stream_task(initial_devices))
-            tg.create_task(xcode_test(location, simulator))
+            tg.create_task(xcode_test(location, simulator=simulator, verbose=verbose))
     except* MySystemExit as e:
         raise SystemExit(*e.exceptions[0].args) from None
     except* subprocess.CalledProcessError as e:
@@ -315,6 +339,11 @@ def main():
         default="iPhone SE (3rd Generation)",
         help="The name of the simulator to use (default: 'iPhone SE (3rd Generation)')",
     )
+    run.add_argument(
+        "-v", "--verbose",
+        action="store_true",
+        help="Enable verbose output",
+    )
 
     try:
         pos = sys.argv.index("--")
@@ -330,7 +359,7 @@ def main():
         clone_testbed(
             source=Path(__file__).parent,
             target=Path(context.location),
-            framework=Path(context.framework) if context.framework else None,
+            framework=Path(context.framework).resolve() if context.framework else None,
             apps=[Path(app) for app in context.apps],
         )
     elif context.subcommand == "run":
@@ -348,6 +377,7 @@ def main():
             asyncio.run(
                 run_testbed(
                     simulator=context.simulator,
+                    verbose=context.verbose,
                     args=test_args,
                 )
             )

iOS/testbed/iOSTestbedTests/iOSTestbedTests.m

@@ -24,8 +24,11 @@ - (void)testPython {
 
     NSString *resourcePath = [[NSBundle mainBundle] resourcePath];
 
-    // Disable all color, as the Xcode log can't display color
+    // Set some other common environment indicators to disable color, as the
+    // Xcode log can't display color. Stdout will report that it is *not* a
+    // TTY.
     setenv("NO_COLOR", "1", true);
+    setenv("PY_COLORS", "0", true);
 
     // Arguments to pass into the test suite runner.
     // argv[0] must identify the process; any subsequent arg