Add buildtool test to run Xcode unit-test targets with xctest

ChangeLog

@@ -1,3 +1,25 @@
+2026-10-29 Daniel Boyd <danieljboyd@icloud.com>
+
+* XCode/PBXProject+Testing.[hm]: New. `buildtool test`: build the
+ project, then run each unit-test target's bundle with xctest
+ (tools-xctest), selected with -target, a scheme's testables and
+ skipped/selected tests, or xcodebuild's -only-testing/-skip-testing.
+ A target whose TEST_HOST names an application in the project runs
+ inside it (xctest -host).
+* XCode/PBXContainer.[hm] (setTestOptions:, test): New.
+* XCode/GNUmakefile: Add PBXProject+Testing.[hm].
+* XCode/PBXProject+Testing.m: -only-testing becomes xctest's -XCTest
+ selection; skipped tests and TEST_HOST use xctest's -skip-testing and
+ -host only when its --help lists them, and fail with a message
+ otherwise.
+* Tools/buildtool/ToolDelegate.m (testOptions:): New. Add the test
+ action; for it, -target and -scheme choose the test targets instead
+ of narrowing the build, so test hosts are still built.
+* Tests/Fixtures/Xcode/unit-tests, Tests/run-buildtool-test-action.sh:
+ New. A project with unit tests, an application and hosted tests, and
+ regressions for `buildtool test`.
+* README.md: Document `buildtool test`.
+
 2026-01-10 Gregory John Casamento <greg.casamento@gmail.com>
 
 * XCode/PBXNativeTarget.m: Include TEST_TYPE in bundle-style

README.md

@@ -100,6 +100,31 @@ Supported xcodebuild-style options:
   `-parallelizeTargets`, `-quiet`, `-verbose`, `-list`, and
   `-showBuildSettings` are accepted for command-line compatibility.
 
+`buildtool test` builds the project, like `xcodebuild test`, then runs each
+unit-test target's `.xctest` bundle with `xctest` from
+[tools-xctest](https://github.com/gnustep/tools-xctest). For `test`,
+`-target` and `-scheme` choose the test targets (a scheme's testables and
+its skipped or selected tests) rather than narrowing the build, so test
+hosts are still built:
+
+```
+buildtool test                                  # every unit-test target
+buildtool test -target MyTests                  # one target
+buildtool test -scheme MyApp                    # a scheme's testables
+buildtool test -only-testing:MyTests/FooTests -skip-testing:MyTests/FooTests/testSlow
+```
+
+`-only-testing:` becomes an `-XCTest` selection, which any tools-xctest
+accepts. Skipping tests (`-skip-testing:`, or a scheme's skipped tests) needs
+an `xctest` that lists `-skip-testing` in its `--help`, and a test target
+whose `TEST_HOST` names an application in the project runs inside that
+application, which needs one that lists `-host` (and an X display, e.g.
+`xvfb-run -a buildtool test`). With an older `xctest`, those targets fail
+with a message saying so. `XCTEST` chooses the `xctest` program, and
+`XCTEST_FLAGS` passes extra options to it (e.g.
+`XCTEST_FLAGS="-junit-report results.xml"`). buildtool exits with status 1
+when the build or any test fails.
+
 Buildtool exits with status 0 on success and nonzero on a failed operation,
 invalid project path, or exception. An explicit project path never falls back
 to another project in the current directory.

Tests/Fixtures/Xcode/unit-tests/App/AppDelegate.h

@@ -0,0 +1,8 @@
+#import <AppKit/AppKit.h>
+
+@interface AppDelegate : NSObject
+{
+  BOOL launched;
+}
+@property BOOL launched;
+@end

Tests/Fixtures/Xcode/unit-tests/App/AppDelegate.m

@@ -0,0 +1,10 @@
+#import "AppDelegate.h"
+
+@implementation AppDelegate
+@synthesize launched;
+
+- (void) applicationDidFinishLaunching: (NSNotification *)notification
+{
+  [self setLaunched: YES];
+}
+@end

Tests/Fixtures/Xcode/unit-tests/App/main.m

@@ -0,0 +1,10 @@
+#import <AppKit/AppKit.h>
+#import "AppDelegate.h"
+
+int main(int argc, const char *argv[])
+{
+  NSApplication *app = [NSApplication sharedApplication];
+  [app setDelegate: [[AppDelegate alloc] init]];
+  [app run];
+  return 0;
+}

Tests/Fixtures/Xcode/unit-tests/AppTests/AppTests.m

@@ -0,0 +1,16 @@
+#import <AppKit/AppKit.h>
+#import <XCTest/XCTest.h>
+
+@interface AppTests : XCTestCase
+@end
+
+@implementation AppTests
+
+- (void) testRunsInsideTheApp
+{
+  XCTAssertNotNil(NSApp);
+  XCTAssertEqualObjects(NSStringFromClass([[NSApp delegate] class]), @"AppDelegate");
+  XCTAssertEqualObjects([(NSObject *)[NSApp delegate] valueForKey: @"launched"], [NSNumber numberWithBool: YES]);
+}
+
+@end