Fix for issue #100

lib/assert.js

@@ -259,47 +259,52 @@ assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
   }
 };
 
-function _throws (shouldThrow, block, err, message) {
-  var exception = null,
-      threw = false,
-      typematters = true;
-
-  message = message || "";
-
-  //handle optional arguments
-  if (arguments.length == 3) {
-    if (typeof(err) == "string") {
-      message = err;
-      typematters = false;
-    }
-  } else if (arguments.length == 2) {
-    typematters = false;
+function expectedException(actual, expected) {
+  if (!actual || !expected) {
+    return false;
+  }
+
+  if (expected instanceof RegExp) {
+    return expected.test(actual);
+  } else if (actual instanceof expected) {
+    return true;
+  } else if (expected.call({}, actual) === true) {
+    return true;
+  }
+
+  return false;
+}
+
+function _throws(shouldThrow, block, expected, message) {
+  var actual;
+
+  if (typeof expected === 'string') {
+    message = expected;
+    expected = null;
   }
 
   try {
     block();
   } catch (e) {
-    threw = true;
-    exception = e;
+    actual = e;
   }
 
-  if (shouldThrow && !threw) {
-    fail( "Missing expected exception"
-        + (err && err.name ? " ("+err.name+")." : '.')
-        + (message ? " " + message : "")
-        );
+  message = (expected && expected.name ? ' (' + expected.name + ').' : '.') +
+            (message ? ' ' + message : '.');
+
+  if (shouldThrow && !actual) {
+    fail('Missing expected exception' + message);
   }
-  if (!shouldThrow && threw && typematters && exception instanceof err) {
-    fail( "Got unwanted exception"
-        + (err && err.name ? " ("+err.name+")." : '.')
-        + (message ? " " + message : "")
-        );
+
+  if (!shouldThrow && expectedException(actual, expected)) {
+    fail('Got unwanted exception' + message);
   }
-  if ((shouldThrow && threw && typematters && !(exception instanceof err)) ||
-      (!shouldThrow && threw)) {
-    throw exception;
+
+  if ((shouldThrow && actual && expected &&
+      !expectedException(actual, expected)) || (!shouldThrow && actual)) {
+    throw actual;
   }
-};
+}
 
 // 11. Expected to throw an error:
 // assert.throws(block, Error_opt, message_opt);

test/test-base.js

@@ -130,6 +130,30 @@ exports.testThrows = makeTest('throws',
         return;
     }]
 );
+exports.testThrowsWithReGex = makeTest('throws',
+    [function () {
+        throw new Error('test');
+    }, /test/],
+    [function () {
+        throw new Error('test');
+    }, /fail/]
+);
+exports.testThrowsWithErrorValidation = makeTest('throws',
+    [function () {
+        throw new Error('test');
+    }, function(err) {
+        if ( (err instanceof Error) && /test/.test(err) ) {
+            return true;
+        }
+    }],
+    [function () {
+        throw new Error('test');
+    }, function(err) {
+        if ( (err instanceof Error) && /fail/.test(err) ) {
+            return true;
+        }
+    }]
+);
 exports.testDoesNotThrows = makeTest('doesNotThrow',
     [function () {
         return;