Core: Better isolate async abstractions

src/assert.js

@@ -15,8 +15,7 @@ QUnit.assert = Assert.prototype = {
 		}
 	},
 
-	// Increment this Test's semaphore counter, then return a function that
-	// decrements that counter a maximum of once.
+	// Put a hold on processing and return a function that will release it a maximum of once.
 	async: function( count ) {
 		var test = this.test,
 			popped = false,
@@ -26,9 +25,8 @@ QUnit.assert = Assert.prototype = {
 			acceptCallCount = 1;
 		}
 
-		test.semaphore += 1;
 		test.usedAsync = true;
-		pauseProcessing( test );
+		internalStop( test );
 
 		return function done() {
 
@@ -42,9 +40,8 @@ QUnit.assert = Assert.prototype = {
 				return;
 			}
 
-			test.semaphore -= 1;
 			popped = true;
-			resumeProcessing( test );
+			internalStart( test );
 		};
 	},
 

src/core.js

@@ -111,7 +111,7 @@ extend( QUnit, {
 			);
 		}
 
-		resumeProcessing();
+		scheduleBegin();
 	},
 
 	config: config,
@@ -138,7 +138,7 @@ extend( QUnit, {
 		config.blocking = false;
 
 		if ( config.autostart ) {
-			resumeProcessing();
+			scheduleBegin();
 		}
 	},
 
@@ -150,6 +150,20 @@ extend( QUnit, {
 
 registerLoggingCallbacks( QUnit );
 
+function scheduleBegin() {
+
+	runStarted = true;
+
+	// Add a slight delay to allow definition of more modules and tests.
+	if ( defined.setTimeout ) {
+		setTimeout( function() {
+			begin();
+		}, 13 );
+	} else {
+		begin();
+	}
+}
+
 function begin() {
 	var i, l,
 		modulesLog = [];
@@ -225,24 +239,19 @@ function pauseProcessing( test ) {
 }
 
 function resumeProcessing( test ) {
-	runStarted = true;
 
 	// A slight delay to allow this iteration of the event loop to finish (more assertions, etc.)
 	if ( defined.setTimeout ) {
 		setTimeout( function() {
-			var current = test || config.current;
-			if ( current && ( current.semaphore > 0 || current.resumed ) ) {
+			if ( test.semaphore > 0 || test.resumed ) {
 				return;
 			}
+			test.resumed = true;
 
 			if ( config.timeout ) {
 				clearTimeout( config.timeout );
 			}
 
-			if ( current ) {
-				current.resumed = true;
-			}
-
 			begin();
 		}, 13 );
 	} else {

src/test.js

@@ -627,16 +627,12 @@ function only( testName, callback ) {
 }
 
 function internalStop( test ) {
-
-	// If a test is running, adjust its semaphore
 	test.semaphore += 1;
 
 	pauseProcessing( test );
 }
 
 function internalStart( test ) {
-
-	// If a test is running, adjust its semaphore
 	test.semaphore -= 1;
 
 	// If semaphore is non-numeric, throw error