Fixed bug where multiple calls to jasmine.Clock.useMock cause multiple tear downs

src/mock-timeout.js

@@ -64,9 +64,9 @@ jasmine.FakeTimer.prototype.runFunctionsWithinRange = function(oldMillis, nowMil
         funcToRun.funcToCall();
         if (funcToRun.recurring) {
           this.scheduleFunction(funcToRun.timeoutKey,
-            funcToRun.funcToCall,
-            funcToRun.millis,
-            true);
+              funcToRun.funcToCall,
+              funcToRun.millis,
+              true);
         }
       } catch(e) {
       }
@@ -110,10 +110,12 @@ jasmine.Clock = {
   },
 
   useMock: function() {
-    var spec = jasmine.getEnv().currentSpec;
-    spec.after(jasmine.Clock.uninstallMock);
+    if (!jasmine.Clock.isInstalled()) {
+      var spec = jasmine.getEnv().currentSpec;
+      spec.after(jasmine.Clock.uninstallMock);
 
-    jasmine.Clock.installMock();
+      jasmine.Clock.installMock();
+    }
   },
 
   installMock: function() {
@@ -121,6 +123,7 @@ jasmine.Clock = {
   },
 
   uninstallMock: function() {
+    jasmine.log("uninstall")
     jasmine.Clock.assertInstalled();
     jasmine.Clock.installed = jasmine.Clock.real;
   },
@@ -133,11 +136,15 @@ jasmine.Clock = {
   },
 
   assertInstalled: function() {
-    if (jasmine.Clock.installed != jasmine.Clock.defaultFakeTimer) {
+    if (!jasmine.Clock.isInstalled()) {
       throw new Error("Mock clock is not installed, use jasmine.Clock.useMock()");
     }
   },
 
+  isInstalled: function() {
+    return jasmine.Clock.installed == jasmine.Clock.defaultFakeTimer;
+  },
+
   installed: null
 };
 jasmine.Clock.installed = jasmine.Clock.real;
@@ -171,7 +178,7 @@ jasmine.getGlobal().clearInterval = function(timeoutKey) {
   if (jasmine.Clock.installed.clearTimeout.apply) {
     return jasmine.Clock.installed.clearInterval.apply(this, arguments);
   } else {
-  return jasmine.Clock.installed.clearInterval(timeoutKey);
+    return jasmine.Clock.installed.clearInterval(timeoutKey);
   }
 };