Add ownPropertyDescriptor assertion.

chaijs · Mar 30, 2015 · 5e1e680 · 5e1e680
1 parent 57df388
commit 5e1e680
Show file tree

Hide file tree

Showing 3 changed files with 118 additions and 1 deletion.
diff --git a/lib/chai/core/assertions.js b/lib/chai/core/assertions.js
@@ -888,6 +888,55 @@ module.exports = function (chai, _) {
   Assertion.addMethod('ownProperty', assertOwnProperty);
   Assertion.addMethod('haveOwnProperty', assertOwnProperty);
 
+  /**
+   * ### .ownPropertyDescriptor(name[, descriptor[, message]])
+   *
+   * Asserts that the target has an own property descriptor `name`, that optionally matches `descriptor`.
+   *
+   *     expect('test').to.have.ownPropertyDescriptor('length');
+   *     expect('test').to.have.ownPropertyDescriptor('length', { enumerable: false, configurable: false, writable: false, value: 4 });
+   *     expect('test').not.to.have.ownPropertyDescriptor('length', { enumerable: false, configurable: false, writable: false, value: 3 });
+   *     expect('test').ownPropertyDescriptor('length').to.have.property('enumerable', false);
+   *     expect('test').ownPropertyDescriptor('length').to.have.keys('value');
+   *
+   * @name ownPropertyDescriptor
+   * @alias haveOwnPropertyDescriptor
+   * @param {String} name
+   * @param {Object} descriptor _optional_
+   * @param {String} message _optional_
+   * @api public
+   */
+
+  function assertOwnPropertyDescriptor (name, descriptor, msg) {
+    if (typeof descriptor === 'string') {
+      msg = descriptor;
+      descriptor = null;
+    }
+    if (msg) flag(this, 'message', msg);
+    var obj = flag(this, 'object');
+    var actualDescriptor = Object.getOwnPropertyDescriptor(Object(obj), name);
+    if (actualDescriptor && descriptor) {
+      this.assert(
+          _.eql(descriptor, actualDescriptor)
+        , 'expected the own property descriptor for ' + _.inspect(name) + ' on #{this} to match ' + _.inspect(descriptor) + ', got ' + _.inspect(actualDescriptor)
+        , 'expected the own property descriptor for ' + _.inspect(name) + ' on #{this} to not match ' + _.inspect(descriptor)
+        , descriptor
+        , actualDescriptor
+        , true
+      );
+    } else {
+      this.assert(
+          actualDescriptor
+        , 'expected #{this} to have an own property descriptor for ' + _.inspect(name)
+        , 'expected #{this} to not have an own property descriptor for ' + _.inspect(name)
+      );
+    }
+    flag(this, 'object', actualDescriptor);
+  }
+
+  Assertion.addMethod('ownPropertyDescriptor', assertOwnPropertyDescriptor);
+  Assertion.addMethod('haveOwnPropertyDescriptor', assertOwnPropertyDescriptor);
+
   /**
    * ### .length(value)
    *

diff --git 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 +531,40 @@ describe('expect', function () {
     }, "blah: expected { length: 12 } to not have own property 'length'");
   });
 
+  it('ownPropertyDescriptor(name)', function(){
+    expect('test').to.have.ownPropertyDescriptor('length');
+    expect('test').to.haveOwnPropertyDescriptor('length');
+    expect('test').not.to.have.ownPropertyDescriptor('foo');
+
+    var obj = {};
+    var descriptor = {
+      configurable: false,
+      enumerable: true,
+      writable: true,
+      value: NaN
+    };
+    Object.defineProperty(obj, 'test', descriptor);
+    expect(obj).to.have.ownPropertyDescriptor('test', descriptor);
+    err(function(){
+      expect(obj).not.to.have.ownPropertyDescriptor('test', descriptor, 'blah');
+    }, "blah: expected the own property descriptor for 'test' on { test: NaN } to not match { configurable: false,\n  enumerable: true,\n  writable: true,\n  value: NaN }");
+    err(function(){
+      var wrongDescriptor = {
+        configurable: false,
+        enumerable: true,
+        writable: false,
+        value: NaN
+      };
+      expect(obj).to.have.ownPropertyDescriptor('test', wrongDescriptor, 'blah');
+    }, "blah: expected the own property descriptor for 'test' on { test: NaN } to match { configurable: false,\n  enumerable: true,\n  writable: false,\n  value: NaN }, got { value: NaN,\n  writable: true,\n  enumerable: true,\n  configurable: false }");
+
+    err(function(){
+      expect(obj).to.have.ownPropertyDescriptor('test2', 'blah');
+    }, "blah: expected { test: NaN } to have an own property descriptor for 'test2'");
+
+    expect(obj).to.have.ownPropertyDescriptor('test').and.have.property('enumerable', true);
+  });
+
   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
@@ -396,6 +396,40 @@ describe('should', function() {
     }, "blah: expected { length: 12 } to not have own property 'length'");
   });
 
+  it('ownPropertyDescriptor(name)', function(){
+    'test'.should.haveOwnPropertyDescriptor('length');
+    'test'.should.have.ownPropertyDescriptor('length');
+    'test'.should.not.have.ownPropertyDescriptor('foo');
+
+    var obj = { };
+    var descriptor = {
+      configurable: false,
+      enumerable: true,
+      writable: true,
+      value: NaN
+    };
+    Object.defineProperty(obj, 'test', descriptor);
+    obj.should.haveOwnPropertyDescriptor('test', descriptor);
+    err(function(){
+      obj.should.not.haveOwnPropertyDescriptor('test', descriptor, 'blah');
+    }, "blah: expected the own property descriptor for 'test' on { test: NaN } to not match { configurable: false,\n  enumerable: true,\n  writable: true,\n  value: NaN }");
+    err(function(){
+      var wrongDescriptor = {
+        configurable: false,
+        enumerable: true,
+        writable: false,
+        value: NaN
+      };
+      obj.should.haveOwnPropertyDescriptor('test', wrongDescriptor, 'blah');
+    }, "blah: expected the own property descriptor for 'test' on { test: NaN } to match { configurable: false,\n  enumerable: true,\n  writable: false,\n  value: NaN }, got { value: NaN,\n  writable: true,\n  enumerable: true,\n  configurable: false }");
+
+    err(function(){
+      obj.should.haveOwnPropertyDescriptor('test2', 'blah');
+    }, "blah: expected { test: NaN } to have an own property descriptor for 'test2'");
+
+    obj.should.have.ownPropertyDescriptor('test').and.have.property('enumerable', true);
+  });
+
   it('string()', function(){
     'foobar'.should.contain.string('bar');
     'foobar'.should.contain.string('foo');