feat: add after build command option

lib/build_verify.dart

@@ -20,6 +20,9 @@ const defaultCommand = [
 /// with the full, platform-specific path to the corresponding executable in the
 /// currently executing SDK.
 ///
+/// If [afterBuildCommand] is specified, it will be run after the build and
+/// has the same behavior as [customCommand].
+///
 /// If provided, [gitDiffPathArguments] are passed as `-- <path>` to `git diff`.
 /// This can be useful if you want to include certain files from the diff
 /// calculation.
@@ -29,10 +32,12 @@ const defaultCommand = [
 Future<void> expectBuildClean({
   String? packageRelativeDirectory,
   List<String> customCommand = defaultCommand,
+  List<String>? afterBuildCommand,
   List<String>? gitDiffPathArguments,
 }) => expectBuildCleanImpl(
   Directory.current.resolveSymbolicLinksSync(),
   command: customCommand,
+  afterBuildCommand: afterBuildCommand,
   packageRelativeDirectory: packageRelativeDirectory,
   gitDiffPathArguments: gitDiffPathArguments,
 );

lib/src/impl.dart

@@ -13,6 +13,7 @@ const dartPlaceHolder = 'DART';
 Future<void> expectBuildCleanImpl(
   String workingDir, {
   List<String> command = defaultCommand,
+  List<String>? afterBuildCommand,
   String? packageRelativeDirectory,
   List<String>? gitDiffPathArguments,
 }) async {
@@ -54,7 +55,19 @@ Future<void> expectBuildCleanImpl(
 
   expectResultOutputSucceeds(result);
 
-  // 3 - get a list of modified files after the build - should still be empty
+  // 3 - run after build command
+  if (afterBuildCommand != null && afterBuildCommand.isNotEmpty) {
+    var executable = afterBuildCommand.first;
+    if (executable == 'DART') {
+      executable = dartPath;
+    }
+
+    final arguments = afterBuildCommand.skip(1).toList();
+
+    await _runProc(executable, arguments, workingDir);
+  }
+
+  // 4 - get a list of modified files after the build - should still be empty
   expect(
     await _changedGeneratedFiles(
       workingDir,

test/integration/simple_integration_test.dart

@@ -61,4 +61,72 @@ void main() {
       );
     });
   });
+
+  group('afterBuildCommand without file changes', () {
+    test(
+      'should succeed if afterBuildCommand does not produce git changes',
+      () async {
+        final afterBuildCommand = [dartPlaceHolder, 'pub', 'get'];
+        await expectBuildCleanImpl(
+          d.sandbox,
+          afterBuildCommand: afterBuildCommand,
+        );
+      },
+    );
+
+    test(
+      'should fail if afterBuildCommand itself fails (e.g. command not exists)',
+      () async {
+        final failingAfterBuildCommand = ['this_command_does_not_exist'];
+
+        await expectLater(
+          expectBuildCleanImpl(
+            d.sandbox,
+            afterBuildCommand: failingAfterBuildCommand,
+          ),
+          throwsA(isA<ProcessException>()),
+        );
+      },
+    );
+  });
+
+  group('afterBuildCommand when a file changes', () {
+    const pubspecLockFileName = 'pubspec.lock';
+
+    setUp(() async {
+      await gitDir.runCommand(['add', pubspecLockFileName]);
+      await gitDir.runCommand(['commit', '-am', 'commit pubspec']);
+    });
+
+    test('should fail if afterBuildCommand produces git changes', () async {
+      final afterBuildCommand = [
+        'sh',
+        '-c',
+        'echo "new content just for this test" > $pubspecLockFileName',
+      ];
+
+      await expectLater(
+        expectBuildCleanImpl(d.sandbox, afterBuildCommand: afterBuildCommand),
+        throwsATestFailure,
+      );
+    });
+
+    test(
+      'should succeed if afterBuildCommand produces git changes which are then '
+      'ignored by gitDiffPathArguments',
+      () async {
+        final afterBuildCommand = [
+          'sh',
+          '-c',
+          'echo "new content just for this test" > $pubspecLockFileName',
+        ];
+
+        await expectBuildCleanImpl(
+          d.sandbox,
+          afterBuildCommand: afterBuildCommand,
+          gitDiffPathArguments: [':!$pubspecLockFileName'],
+        );
+      },
+    );
+  });
 }