Run package:test tests on mac (#2280)

This will exercise things like launching browsers (where they are
currently working on CI).

Add `osx` to the sharded `package:test` tests alongside `windows`. These
exercise the majority of OS specific behavior.

Skip existing safari tests due to a bug running tests in non-interactive
environments. (#1253)

Skip existing firefox tests due to a changed executable path. (Planned
fix in #2276)

Refactor a ternary chain to an if/else chain to add the extra
conditions for firefox and safari.

pkgs/test/mono_pkg.yaml

@@ -22,25 +22,30 @@ stages:
   - command: dart test --preset travis --total-shards 5 --shard-index 0
     os:
     - windows
+    - osx
     sdk:
     - pubspec
   - command: dart test --preset travis --total-shards 5 --shard-index 1
     os:
     - windows
+    - osx
     sdk:
     - pubspec
   - command: dart test --preset travis --total-shards 5 --shard-index 2
     os:
     - windows
+    - osx
     sdk:
     - pubspec
   - command: dart test --preset travis --total-shards 5 --shard-index 3
     os:
     - windows
+    - osx
     sdk:
     - pubspec
   - command: dart test --preset travis --total-shards 5 --shard-index 4
     os:
     - windows
+    - osx
     sdk:
     - pubspec

pkgs/test/test/runner/browser/safari_test.dart

@@ -18,7 +18,8 @@ import 'code_server.dart';
 void main() {
   setUpAll(precompileTestExecutable);
 
-  test('starts Safari with the given URL', () async {
+  test('starts Safari with the given URL',
+      skip: 'https://github.com/dart-lang/test/issues/1253', () async {
     var server = await CodeServer.start();
 
     server.handleJavaScript('''
@@ -54,7 +55,8 @@ webSocket.addEventListener("open", function() {
             startsWith('Failed to run Safari: $noSuchFileMessage'))));
   });
 
-  test('can run successful tests', () async {
+  test('can run successful tests',
+      skip: 'https://github.com/dart-lang/test/issues/1253', () async {
     await d.file('test.dart', '''
 import 'package:test/test.dart';
 

pkgs/test/test/runner/compiler_runtime_matrix_test.dart

@@ -26,8 +26,19 @@ void main() {
           (runtime == Runtime.safari && !Platform.isMacOS)) {
         continue;
       }
+      String? skipReason;
+      if (runtime == Runtime.safari) {
+        skipReason = 'https://github.com/dart-lang/test/issues/1253';
+      } else if (compiler == Compiler.dart2wasm) {
+        skipReason = 'Wasm tests are experimental and require special setup';
+      } else if ([Runtime.firefox, Runtime.nodeJS].contains(runtime) &&
+          Platform.isWindows) {
+        skipReason = 'https://github.com/dart-lang/test/issues/1942';
+      } else if (runtime == Runtime.firefox && Platform.isMacOS) {
+        skipReason = 'https://github.com/dart-lang/test/pull/2276';
+      }
       group('--runtime ${runtime.identifier} --compiler ${compiler.identifier}',
-          () {
+          skip: skipReason, () {
         final testArgs = [
           'test.dart',
           '-p',
@@ -112,13 +123,7 @@ void main() {
                   ? 'https://github.com/dart-lang/test/issues/2150'
                   : null);
         }
-      },
-          skip: compiler == Compiler.dart2wasm
-              ? 'Wasm tests are experimental and require special setup'
-              : [Runtime.firefox, Runtime.nodeJS].contains(runtime) &&
-                      Platform.isWindows
-                  ? 'https://github.com/dart-lang/test/issues/1942'
-                  : null);
+      });
     }
   }
 }