Add timeout tests for the pool package.

pkg/pool/test/pool_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 
+import 'package:fake_async/fake_async.dart';
 import 'package:pool/pool.dart';
 import 'package:stack_trace/stack_trace.dart';
 import 'package:unittest/unittest.dart';
 
 void main() {
   group("request()", () {
     test("resources can be requested freely up to the limit", () {
       var pool = new Pool(50);
       var requests = [];
       for (var i = 0; i < 50; i++) {
         expect(pool.request(), completes);
       }
     });
 
     test("resources block past the limit", () {
-      var pool = new Pool(50);
-      var requests = [];
-      for (var i = 0; i < 50; i++) {
-        expect(pool.request(), completes);
-      }
-      expect(pool.request(), doesNotComplete);
+      new FakeAsync().run((async) {
+        var pool = new Pool(50);
+        var requests = [];
+        for (var i = 0; i < 50; i++) {
+          expect(pool.request(), completes);
+        }
+        expect(pool.request(), doesNotComplete);
+
+        async.elapse(new Duration(seconds: 1));
+      });
     });
 
     test("a blocked resource is allocated when another is released", () {
-      var pool = new Pool(50);
-      var requests = [];
-      for (var i = 0; i < 49; i++) {
-        expect(pool.request(), completes);
-      }
+      new FakeAsync().run((async) {
+        var pool = new Pool(50);
+        var requests = [];
+        for (var i = 0; i < 49; i++) {
+          expect(pool.request(), completes);
+        }
 
-      return pool.request().then((lastAllocatedResource) {
-        var blockedResource = pool.request();
+        pool.request().then((lastAllocatedResource) {
+          // This will only complete once [lastAllocatedResource] is released.
+          expect(pool.request(), completes);
 
-        return pumpEventQueue().then((_) {
-          lastAllocatedResource.release();
-          return pumpEventQueue();
-        }).then((_) {
-          expect(blockedResource, completes);
+          new Future.delayed(new Duration(microseconds: 1)).then((_) {
+            lastAllocatedResource.release();
+          });
         });
+
+        async.elapse(new Duration(seconds: 1));
       });
     });
   });
 
   group("withResource()", () {
     test("can be called freely up to the limit", () {
       var pool = new Pool(50);
       var requests = [];
       for (var i = 0; i < 50; i++) {
         pool.withResource(expectAsync(() => new Completer().future));
       }
     });
 
     test("blocks the callback past the limit", () {
-      var pool = new Pool(50);
-      var requests = [];
-      for (var i = 0; i < 50; i++) {
-        pool.withResource(expectAsync(() => new Completer().future));
-      }
-      pool.withResource(expectNoAsync());
+      new FakeAsync().run((async) {
+        var pool = new Pool(50);
+        var requests = [];
+        for (var i = 0; i < 50; i++) {
+          pool.withResource(expectAsync(() => new Completer().future));
+        }
+        pool.withResource(expectNoAsync());
+
+        async.elapse(new Duration(seconds: 1));
+      });
     });
 
     test("a blocked resource is allocated when another is released", () {
-      var pool = new Pool(50);
-      var requests = [];
-      for (var i = 0; i < 49; i++) {
-        pool.withResource(expectAsync(() => new Completer().future));
-      }
+      new FakeAsync().run((async) {
+        var pool = new Pool(50);
+        var requests = [];
+        for (var i = 0; i < 49; i++) {
+          pool.withResource(expectAsync(() => new Completer().future));
+        }
 
-      var completer = new Completer();
-      var lastAllocatedResource = pool.withResource(() => completer.future);
-      var blockedResourceAllocated = false;
-      var blockedResource = pool.withResource(() {
-        blockedResourceAllocated = true;
-      });
+        var completer = new Completer();
+        var lastAllocatedResource = pool.withResource(() => completer.future);
+        var blockedResourceAllocated = false;
+        var blockedResource = pool.withResource(() {
+          blockedResourceAllocated = true;
+        });
 
-      return pumpEventQueue().then((_) {
-        expect(blockedResourceAllocated, isFalse);
-        completer.complete();
-        return pumpEventQueue();
-      }).then((_) {
-        expect(blockedResourceAllocated, isTrue);
+        new Future.delayed(new Duration(microseconds: 1)).then((_) {
+          expect(blockedResourceAllocated, isFalse);
+          completer.complete();
+          return new Future.delayed(new Duration(microseconds: 1));
+        }).then((_) {
+          expect(blockedResourceAllocated, isTrue);
+        });
+
+        async.elapse(new Duration(seconds: 1));
       });
     });
   });
 
-  // TODO(nweiz): test timeouts when seaneagan's fake_async package lands.
-}
+  group("with a timeout", () {
+    test("doesn't time out if there are no pending requests", () {
+      new FakeAsync().run((async) {
+        var pool = new Pool(50, timeout: new Duration(seconds: 5));
+        for (var i = 0; i < 50; i++) {
+          expect(pool.request(), completes);
+        }
 
-/// Returns a [Future] that completes after pumping the event queue [times]
-/// times. By default, this should pump the event queue enough times to allow
-/// any code to run, as long as it's not waiting on some external event.
-Future pumpEventQueue([int times = 20]) {
-  if (times == 0) return new Future.value();
-  // We use a delayed future to allow microtask events to finish. The
-  // Future.value or Future() constructors use scheduleMicrotask themselves and
-  // would therefore not wait for microtask callbacks that are scheduled after
-  // invoking this method.
-  return new Future.delayed(Duration.ZERO, () => pumpEventQueue(times - 1));
+        async.elapse(new Duration(seconds: 6));
+      });
+    });
+
+    test("resets the timer if a resource is returned", () {
+      new FakeAsync().run((async) {
+        var pool = new Pool(50, timeout: new Duration(seconds: 5));
+        for (var i = 0; i < 49; i++) {
+          expect(pool.request(), completes);
+        }
+
+        pool.request().then((lastAllocatedResource) {
+          // This will only complete once [lastAllocatedResource] is released.
+          expect(pool.request(), completes);
+
+          new Future.delayed(new Duration(seconds: 3)).then((_) {
+            lastAllocatedResource.release();
+            expect(pool.request(), doesNotComplete);
+          });
+        });
+
+        async.elapse(new Duration(seconds: 6));
+      });
+    });
+
+    test("resets the timer if a resource is requested", () {
+      new FakeAsync().run((async) {
+        var pool = new Pool(50, timeout: new Duration(seconds: 5));
+        for (var i = 0; i < 50; i++) {
+          expect(pool.request(), completes);
+        }
+        expect(pool.request(), doesNotComplete);
+
+        new Future.delayed(new Duration(seconds: 3)).then((_) {
+          expect(pool.request(), doesNotComplete);
+        });
+
+        async.elapse(new Duration(seconds: 6));
+      });
+    });    
+
+    test("times out if nothing happens", () {
+      new FakeAsync().run((async) {
+        var pool = new Pool(50, timeout: new Duration(seconds: 5));
+        for (var i = 0; i < 50; i++) {
+          expect(pool.request(), completes);
+        }
+        expect(pool.request(), throwsA(new isInstanceOf<TimeoutException>()));
+
+        async.elapse(new Duration(seconds: 6));
+      });
+    });    
+  });
 }
 
 /// Returns a function that will cause the test to fail if it's called.
 ///
-/// This won't let the test complete until it's confident that the function
-/// won't be called.
+/// This should only be called within a [FakeAsync.run] zone.
 Function expectNoAsync() {
-  // Make sure the test lasts long enough for the function to get called if it's
-  // going to get called.
-  expect(pumpEventQueue(), completes);
-
   var stack = new Trace.current(1);
   return () => handleExternalError(
       new TestFailure("Expected function not to be called."), "",
       stack);
 }
 
 /// A matcher for Futures that asserts that they don't complete.
 ///
-/// This won't let the test complete until it's confident that the function
-/// won't be called.
+/// This should only be called within a [FakeAsync.run] zone.
 Matcher get doesNotComplete => predicate((future) {
   expect(future, new isInstanceOf<Future>('Future'));
-  // Make sure the test lasts long enough for the function to get called if it's
-  // going to get called.
-  expect(pumpEventQueue(), completes);
 
   var stack = new Trace.current(1);
   future.then((_) => handleExternalError(
       new TestFailure("Expected future not to complete."), "",
       stack));
   return true;
 });