Add futures to wait for evaluate to execute

Author: srujzs

dwds/test/hot_reload_test.dart

@@ -7,6 +7,8 @@
 @Timeout(Duration(minutes: 5))
 library;
 
+import 'dart:async';
+
 import 'package:dwds/expression_compiler.dart';
 import 'package:test/test.dart';
 import 'package:test_common/logging.dart';
@@ -46,6 +48,20 @@ void main() {
     await recompile();
   }
 
+  /// Wait for `evaluate` to finish executing before checking expectations by
+  /// checking for a log output.
+  Future<void> waitForEvaluateToExecute() async {
+    final completer = Completer<void>();
+    final expectedString = 'evaluate executed';
+    final subscription = context.webkitDebugger.onConsoleAPICalled.listen((e) {
+      if (e.args.first.value == expectedString) {
+        completer.complete();
+      }
+    });
+    await completer.future;
+    await subscription.cancel();
+  }
+
   group('Injected client', () {
     late VmService fakeClient;
 
@@ -81,8 +97,10 @@ void main() {
       expect(source, contains(originalString));
       expect(source.contains(newString), false);
 
+      final evaluateDone = waitForEvaluateToExecute();
       final rootLib = isolate.rootLib;
       await client.evaluate(isolate.id!, rootLib!.id!, 'evaluate()');
+      await evaluateDone;
       source = await context.webDriver.pageSource;
       expect(source, contains(newString));
       expect(source.contains(originalString), false);
@@ -99,8 +117,10 @@ void main() {
       var report = await fakeClient.reloadSources(isolate.id!);
       expect(report.success, true);
 
+      var evaluateDone = waitForEvaluateToExecute();
       final rootLib = isolate.rootLib;
       await client.evaluate(isolate.id!, rootLib!.id!, 'evaluate()');
+      await evaluateDone;
       var source = await context.webDriver.pageSource;
       expect(source, contains(originalString));
       expect(source.contains(newString), false);
@@ -110,7 +130,9 @@ void main() {
       report = await fakeClient.reloadSources(isolate.id!);
       expect(report.success, true);
 
+      evaluateDone = waitForEvaluateToExecute();
       await client.evaluate(isolate.id!, rootLib.id!, 'evaluate()');
+      await evaluateDone;
       source = await context.webDriver.pageSource;
       expect(source, contains(newString));
       expect(source.contains(originalString), false);
@@ -120,7 +142,9 @@ void main() {
       report = await fakeClient.reloadSources(isolate.id!);
       expect(report.success, true);
 
+      evaluateDone = waitForEvaluateToExecute();
       await client.evaluate(isolate.id!, rootLib.id!, 'evaluate()');
+      await evaluateDone;
       source = await context.webDriver.pageSource;
       expect(source, contains(newString));
       expect(source.contains(originalString), false);

fixtures/_test_hot_reload/web/main.dart

@@ -7,11 +7,17 @@ import 'dart:js_interop';
 
 import 'package:_test_hot_reload/library1.dart';
 
+@JS('console.log')
+external void log(String _);
+
 @JS('document.body.innerHTML')
 external set innerHtml(String html);
 
 void evaluate() {
   innerHtml = 'Program is running!\n $reloadValue}\n';
+
+  // Wait for this print statement so that we know evaluate is done executing.
+  log('evaluate executed');
 }
 
 void main() {