[3.9] pythongh-127845: Minor improvements to iOS test runner script (pythonGH-127846) (python#127892)

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.
(cherry picked from commit ba2d2fd)

Co-authored-by: Russell Keith-Magee <[email protected]>

Author: miss-islington

Makefile.pre.in

@@ -1286,7 +1286,7 @@ 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 testall, but with only one pass and without multiple processes.
 # Run an optional script to include information about the build environment.

iOS/testbed/__main__.py

@@ -7,6 +7,7 @@
 import sys
 from contextlib import asynccontextmanager
 from datetime import datetime
+from itertools import chain
 from pathlib import Path
 
 
@@ -141,10 +142,12 @@ 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",
@@ -159,18 +162,33 @@ 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)
 
 
+# A backport of Path.relative_to(*, walk_up=True)
+def relative_to(target, other):
+    for step, path in enumerate(chain([other], other.parents)):
+        if path == target or path in target.parents:
+            break
+    else:
+        raise ValueError(f"{str(target)!r} and {str(other)!r} have different anchors")
+    parts = ['..'] * step + list(target.parts[len(path.parts):])
+    return Path("/".join(parts))
+
+
 def clone_testbed(
     source: Path,
     target: Path,
@@ -182,7 +200,9 @@ 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 +222,48 @@ 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(
+                relative_to(framework, xc_framework_path.parent)
+            )
+            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(
+                relative_to(framework, sim_framework_path.parent)
             )
-            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 +278,11 @@ 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
@@ -256,10 +292,10 @@ 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))
-    except* MySystemExit as e:
+            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:
+    except subprocess.CalledProcessError as e:
         # Extract it from the ExceptionGroup so it can be handled by `main`.
         raise e.exceptions[0]
 
@@ -315,6 +351,11 @@ 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 +371,7 @@ 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 +389,7 @@ 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