Stabilize volume unit tests by waiting for exact state

Wait for specific final state instead of waiting for specific number of
operations in volume unit tests. The tests are more readable and will survive
random goroutine ordering (PV and PVC controller have both their own
goroutine).

pkg/controller/volume/persistentvolume/controller_test.go

@@ -33,7 +33,6 @@ import (
 // can't reliably simulate periodic sync of volumes/claims - it would be
 // either very timing-sensitive or slow to wait for real periodic sync.
 func TestControllerSync(t *testing.T) {
-	expectedChanges := []int{4, 1, 1, 2, 1, 1, 1}
 	tests := []controllerTest{
 		// [Unit test set 5] - controller tests.
 		// We test the controller as if
@@ -157,7 +156,7 @@ func TestControllerSync(t *testing.T) {
 		},
 	}
 
-	for ix, test := range tests {
+	for _, test := range tests {
 		glog.V(4).Infof("starting test %q", test.name)
 
 		// Initialize the controller
@@ -176,7 +175,6 @@ func TestControllerSync(t *testing.T) {
 		}
 
 		// Start the controller
-		count := reactor.getChangeCount()
 		go ctrl.Run()
 
 		// Wait for the controller to pass initial sync and fill its caches.
@@ -199,13 +197,10 @@ func TestControllerSync(t *testing.T) {
 		ctrl.claims.Resync()
 		ctrl.volumes.store.Resync()
 
-		// Wait at least once, just in case expectedChanges[ix] == 0
-		reactor.waitTest()
-		// Wait for expected number of operations.
-		for reactor.getChangeCount() < count+expectedChanges[ix] {
-			reactor.waitTest()
+		err = reactor.waitTest(test)
+		if err != nil {
+			t.Errorf("Failed to run test %s: %v", test.name, err)
 		}
-
 		ctrl.Stop()
 
 		evaluateTestResults(ctrl, reactor, test, t)