Run the test's heartbeat whenever the process emits output

CHANGELOG.md

@@ -1,4 +1,6 @@
-## 1.0.5-dev
+## 1.0.5
+
+* Don't allow the test to time out as long as the process is emitting output.
 
 ## 1.0.4
 

lib/test_process.dart

@@ -134,11 +134,13 @@ class TestProcess {
     // Call [split] explicitly because we don't want to log overridden
     // [stdoutStream] or [stderrStream] output.
     _stdoutSplitter.split().listen((line) {
+      _heartbeat();
       if (forwardStdio) print(line);
       _log.add('    $line');
     });
 
     _stderrSplitter.split().listen((line) {
+      _heartbeat();
       if (forwardStdio) print(line);
       _log.add('[e] $line');
     });
@@ -232,4 +234,12 @@ class TestProcess {
     expect(exitCode, expectedExitCode,
         reason: 'Process `$description` had an unexpected exit code.');
   }
+
+  /// Signal to the test runner that the test is still making progress and
+  /// shouldn't time out.
+  void _heartbeat() {
+    // Interacting with the test runner's asynchronous expectation logic will
+    // notify it that the test is alive.
+    expectAsync0(() {})();
+  }
 }

pubspec.yaml

@@ -1,5 +1,5 @@
 name: test_process
-version: 1.0.5-dev
+version: 1.0.5
 
 description: A package for testing subprocesses.
 homepage: https://github.com/dart-lang/test_process