add optional 2. arg to QUnit.raises qunitjs#69.

qunit/qunit.js

@@ -338,14 +338,37 @@ var QUnit = {
 		QUnit.push(expected !== actual, actual, expected, message);
 	},
 
-	raises: function(fn,  message) {
+	raises: function(block, expected, message) {
+		var actual, ok = false;
+
+		if (typeof expected === 'string') {
+			message = expected;
+			expected = null;
+		}
+
 		try {
-			fn();
-			QUnit.ok( false, message );
+			block();
+		} catch (e) {
+			actual = e;
 		}
-		catch (e) {
-			QUnit.ok( true, message );
+
+		if (actual) {
+			// we don't want to validate thrown error
+			if (!expected) {
+				ok = true;
+			// expected is a regexp	
+			} else if (QUnit.objectType(expected) === "regexp") {
+				ok = expected.test(actual);
+			// expected is a constructor	
+			} else if (actual instanceof expected) {
+				ok = true;
+			// expected is a validation function which returns true is validation passed	
+			} else if (expected.call({}, actual) === true) {
+				ok = true;
+			}
 		}
+
+		QUnit.ok(ok, message);
 	},
 
 	start: function() {

test/test.js

@@ -207,19 +207,45 @@ test("jsDump output", function() {
 });
 
 module("assertions");
-test("raises", function() {
-	function thrower1() {
-		throw 'Errored!';
+test("raises",function() {
+	function CustomError( message ) {
+		this.message = message;
 	}
-	function thrower2() {
-		throw new TypeError("Type!");
-	}
-	function thrower3() {
-		throw {message:"Custom!"};
-	}
-	raises(thrower1, 'Errored!', 'throwing string');
-	raises(thrower2, 'Type!', 'throwing TypeError instance');
-	raises(thrower3, 'Custom!', 'throwing custom object');
+
+	CustomError.prototype.toString = function() {
+		return this.message;	
+	};
+
+
+
+	raises(
+		function() {
+			throw new CustomError();
+		},
+		CustomError,
+		'raised error is an instance of CustomError'
+	);
+
+	raises(
+		function() {
+			throw new CustomError("some error description");
+		},
+		/description/,
+		"raised error message contains 'description'"
+	);
+
+	raises(
+		function() {
+			throw new CustomError("some error description");
+		},
+		function( err ) {
+			if ( (err instanceof CustomError) && /description/.test(err) ) {
+				return true;
+			}
+		},
+		"custom validation function"		
+	);	
+
 });
 
 if (typeof document !== "undefined") {