Index: testrunner.js
===================================================================
--- testrunner.js	(revision 6272)
+++ testrunner.js	(working copy)
@@ -224,6 +224,7 @@
 	expect: expect,
 	ok: ok,
 	equals: equals,
+	raises: raises,
 	start: start,
 	stop: stop,
 	reset: reset,
@@ -590,6 +591,24 @@
 	push(expected == actual, actual, expected, message);
 }
 
+/**
+ * Checks that the given expression throws an exception of the expected type, with an optional message.
+ *
+ * @example raises( function() { return foo.bar; }, "TypeError", "invalid property access raises TypeError exception" );
+ *
+ * @param Function expression
+ * @param String expected exception type
+ * @param String message (optional)
+ */
+function raises(expression, expected, message) {
+	try {
+		push(false, expression(), expected, message);
+	} catch(ex) {
+		push(ex.name == expected, ex.name, expected, message);
+	}
+}
+
 function push(result, actual, expected, message) {
 	message = message || (result ? "okay" : "failed");
 	QUnit.ok( result, result ? message + ": " + expected : message + ", expected: " + jsDump.parse(expected) + " result: " + jsDump.parse(actual) );