Merge pull request #403 from cjqed/3.x.x

Assert ifError now throws the error passed in, to keep it consistent wit...

lib/chai/interface/assert.js

@@ -1243,11 +1243,24 @@ module.exports = function (chai, util) {
   }
 
   /*!
-   * Undocumented / untested
+   * ### .ifError(object)
+   *
+   * Asserts if value is not a false value, and throws if it is a true value.
+   * This is added to allow for chai to be a drop-in replacement for Node's 
+   * assert class.
+   *
+   *     var err = new Error('I am a custom error');
+   *     assert.ifError(err); // Rethrows err!
+   *
+   * @name ifError
+   * @param {Object} object
+   * @api public
    */
 
-  assert.ifError = function (val, msg) {
-    new Assertion(val, msg).to.not.be.ok;
+  assert.ifError = function (val) {
+    if (val) {
+      throw(val);
+    }
   };
 
   /*!

test/assert.js

@@ -551,8 +551,9 @@ describe('assert', function () {
     assert.ifError(undefined);
 
     err(function () {
-      assert.ifError('foo');
-     }, "expected \'foo\' to be falsy");
+      var err = new Error('This is an error message');
+      assert.ifError(err);
+     }, 'This is an error message');
   });
 
   it('operator', function() {