From a75fdfa0b4e5185733d43868e92ee104003bc7b9 Mon Sep 17 00:00:00 2001
From: Jordan Harband <ljharb@gmail.com>
Date: Tue, 24 Mar 2015 21:29:56 -0700
Subject: [PATCH] Add `enumerableProperty` assertion.

---
 lib/chai/core/assertions.js | 28 ++++++++++++++++++++++++++++
 test/expect.js              | 12 +++++++++++-
 test/should.js              | 10 ++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/lib/chai/core/assertions.js b/lib/chai/core/assertions.js
index ac838837e..8b9fb1811 100644
--- a/lib/chai/core/assertions.js
+++ b/lib/chai/core/assertions.js
@@ -888,6 +888,34 @@ module.exports = function (chai, _) {
   Assertion.addMethod('ownProperty', assertOwnProperty);
   Assertion.addMethod('haveOwnProperty', assertOwnProperty);
 
+  /**
+   * ### .enumerableProperty(name)
+   *
+   * Asserts that the target has an enumerable property `name`.
+   *
+   *     expect('test').not.to.have.enumerableProperty('length');
+   *
+   * @name enumerableProperty
+   * @alias haveEnumerableProperty
+   * @param {String} name
+   * @param {String} message _optional_
+   * @api public
+   */
+
+  function assertEnumerableProperty (name, msg) {
+    if (msg) flag(this, 'message', msg);
+    var obj = flag(this, 'object');
+    var descriptor = Object.getOwnPropertyDescriptor(Object(obj), name);
+    this.assert(
+        descriptor && descriptor.enumerable
+      , 'expected #{this} to have enumerable property ' + _.inspect(name)
+      , 'expected #{this} not to have enumerable property ' + _.inspect(name)
+    );
+  }
+
+  Assertion.addMethod('enumerableProperty', assertEnumerableProperty);
+  Assertion.addMethod('haveEnumerableProperty', assertEnumerableProperty);
+
   /**
    * ### .length(value)
    *
diff --git a/test/expect.js b/test/expect.js
index 0d11c67e6..38cf95270 100644
--- a/test/expect.js
+++ b/test/expect.js
@@ -467,7 +467,7 @@ describe('expect', function () {
     err(function(){
       expect(deepObj).to.have.deep.property('teas[3].tea', 'bar');
     }, "expected { Object (green, teas) } to have a deep property 'teas[3].tea'");
-    
+
     var arr = [
         [ 'chai', 'matcha', 'konacha' ]
       , [ { tea: 'chai' }
@@ -531,6 +531,16 @@ describe('expect', function () {
     }, "blah: expected { length: 12 } to not have own property 'length'");
   });
 
+  it('enumerableProperty(name)', function(){
+    expect('test').not.to.have.enumerableProperty('length');
+    expect('test').not.to.haveEnumerableProperty('length');
+    expect({ length: 12 }).to.have.enumerableProperty('length');
+
+    err(function(){
+      expect({ length: 12 }).not.to.have.enumerableProperty('length', 'blah');
+    }, "blah: expected { length: 12 } not to have enumerable property 'length'");
+  });
+
   it('string()', function(){
     expect('foobar').to.have.string('bar');
     expect('foobar').to.have.string('foo');
diff --git a/test/should.js b/test/should.js
index 4c18e03b0..33f95d63e 100644
--- a/test/should.js
+++ b/test/should.js
@@ -396,6 +396,16 @@ describe('should', function() {
     }, "blah: expected { length: 12 } to not have own property 'length'");
   });
 
+  it('enumerableProperty(name)', function(){
+    'test'.should.not.have.enumerableProperty('length');
+    'test'.should.not.haveEnumerableProperty('length');
+    ({ length: 12 }).should.have.enumerableProperty('length');
+
+    err(function(){
+      ({ length: 12 }).should.not.have.enumerableProperty('length', 'blah');
+    }, "blah: expected { length: 12 } not to have enumerable property 'length'");
+  });
+
   it('string()', function(){
     'foobar'.should.contain.string('bar');
     'foobar'.should.contain.string('foo');