[concurrency] Add an end<->end test for nonisolated inherits isolation.

Author: gottesmm

test/Concurrency/Runtime/nonisolated_inherits_isolation.swift

@@ -0,0 +1,94 @@
+// RUN: %target-run-simple-swift( -swift-version 6 -g %import-libdispatch -import-objc-header %S/Inputs/RunOnMainActor.h -enable-experimental-feature NonIsolatedAsyncInheritsIsolationFromContext )
+
+// REQUIRES: executable_test
+// REQUIRES: concurrency
+// REQUIRES: concurrency_runtime
+// REQUIRES: libdispatch
+// REQUIRES: asserts
+
+// REQUIRES: swift_feature_NonIsolatedAsyncInheritsIsolationFromContext
+
+// UNSUPPORTED: freestanding
+
+import StdlibUnittest
+
+////////////////////////
+// MARK: Declarations //
+////////////////////////
+
+@_silgen_name("dispatch_assert_queue")
+func dispatch_assertQueue(_ ptr: UnsafeRawPointer)
+
+func checkIfOnMainQueue() {
+  dispatch_assertQueue(getDispatchMain())
+}
+
+actor Custom {
+}
+
+@globalActor
+struct CustomActor {
+  static var shared: Custom {
+    return Custom()
+  }
+}
+
+let tests = TestSuite("NonIsolatedInheritsIsolation")
+
+tests.test("checkIfOnMainQueue does not crash on the main queue") { @MainActor () -> () in
+  expectCrashLater()
+  checkIfOnMainQueue()
+}
+
+tests.test("checkIfOnMainQueue does not crash on the main queue") { @MainActor () async -> () in
+  checkIfOnMainQueue()
+}
+
+tests.test("checkIfOnMainQueue crashes off the main queue") {
+  expectCrashLater()
+  await { @CustomActor in
+    print("=> checkIfOnMainQueue crashes off the main queue")
+    checkIfOnMainQueue()
+  }()
+}
+
+tests.test("checkIfOnMainQueue crashes off the main queue 2") { @CustomActor () async -> () in
+  expectCrashLater()
+  print("=> checkIfOnMainQueue crashes off the main queue 2")
+  checkIfOnMainQueue()
+}
+
+/////////////////
+// MARK: Tests //
+/////////////////
+
+nonisolated func nonisolatedCheckIfOnMainQueue() async {
+  checkIfOnMainQueue()
+}
+
+tests.test("Check if nonisolated inherits MainActor does not crash") { @MainActor () async -> () in
+  await nonisolatedCheckIfOnMainQueue()
+}
+
+tests.test("Check if nonisolated inherits CustomActor crashes") { @CustomActor () async -> () in
+  expectCrashLater()
+  await nonisolatedCheckIfOnMainQueue()
+}
+
+tests.test("Check if nonisolated inheriting nonisolated crashes") { () async -> () in
+  // By default this closure is @MainActor isolated. We detach on a background
+  // thread and sleep 5 seconds to get the crash. The crash should happen
+  // quicker than 5 seconds... we just want to make sure that the code does not
+  // exit before we crash.
+  expectCrashLater()
+  Task.detached {
+    await nonisolatedCheckIfOnMainQueue()
+  }
+  sleep(5)
+}
+
+@MainActor func run() async {
+  await runAllTestsAsync()
+}
+
+await run()