From fe3d8f2411209b202b7fe74cb48b582ffc5cfc5f Mon Sep 17 00:00:00 2001
From: Mikeal Rogers <mikeal.rogers@gmail.com>
Date: Fri, 21 May 2010 12:05:55 -0700
Subject: [PATCH] Add assert.ifError

---
 doc/api.markdown           | 3 +++
 lib/assert.js              | 1 +
 test/simple/test-assert.js | 3 +++
 3 files changed, 7 insertions(+)

diff --git a/doc/api.markdown b/doc/api.markdown
index 6afc4661af..c2467a15bc 100644
--- a/doc/api.markdown
+++ b/doc/api.markdown
@@ -2546,6 +2546,9 @@ Expects `block` to throw an error.
 
 Expects `block` not to throw an error.
 
+### assert.ifError(value)
+
+Tests if value is not a false value, throws if it is a true value. Useful when testing the first argument, `error` in callbacks.
 
 ## Path
 
diff --git a/lib/assert.js b/lib/assert.js
index da9198a8d8..2d1fc08001 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -284,3 +284,4 @@ assert.doesNotThrow = function(block, /*optional*/error, /*optional*/message) {
   _throws.apply(this, [false].concat(pSlice.call(arguments)));
 };
 
+assert.ifError = function (err) { if (err) {throw err;}};
diff --git a/test/simple/test-assert.js b/test/simple/test-assert.js
index 610236856a..10aeb5cc58 100644
--- a/test/simple/test-assert.js
+++ b/test/simple/test-assert.js
@@ -154,3 +154,6 @@ try {
 }
 assert.equal(true,threw,'a.doesNotThrow is not catching type matching errors');
 
+assert.throws(function () {assert.ifError(new Error('test error'))});
+assert.doesNotThrow(function(){assert.ifError(null)});
+assert.doesNotThrow(function(){assert.ifError()});