Add toBeTextComponentWithValue to reactComponentExpect

This was previously possible by looking at renderedChildren and props
but this feels better.

src/core/__tests__/ReactMultiChildText-test.js

@@ -70,7 +70,7 @@ var expectChildren = function(d, children) {
       if (typeof child === 'string') {
         reactComponentExpect(d)
           .expectRenderedChildAt(i)
-          .toBeTextComponent();
+          .toBeTextComponentWithValue(child);
 
         textNode = d.getDOMNode().childNodes[i].firstChild;
 

src/test/__tests__/reactComponentExpect-test.js

@@ -0,0 +1,49 @@
+/**
+ * Copyright 2013-2014, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *
+ * @emails react-core
+ */
+
+"use strict";
+
+var React;
+var ReactTestUtils;
+var reactComponentExpect;
+
+var mocks;
+var warn;
+
+describe('reactComponentExpect', function() {
+
+  beforeEach(function() {
+    React = require('React');
+    ReactTestUtils = require('ReactTestUtils');
+    reactComponentExpect = require('reactComponentExpect');
+  });
+
+  it('should detect text components', function() {
+    var SomeComponent = React.createClass({
+      render: function() {
+        return (
+          <div>
+            <div>This is a div</div>
+            {'This is text'}
+          </div>
+        );
+      }
+    });
+
+    var component = ReactTestUtils.renderIntoDocument(<SomeComponent />);
+
+    reactComponentExpect(component)
+      .expectRenderedChild()
+      .expectRenderedChildAt(1)
+      .toBeTextComponentWithValue('This is text');
+  });
+});
+

src/test/reactComponentExpect.js

@@ -139,9 +139,10 @@ assign(reactComponentExpectInternal.prototype, {
     return this;
   },
 
-  toBeTextComponent: function() {
+  toBeTextComponentWithValue: function(val) {
     var elementType = typeof this._instance._currentElement;
     expect(elementType === 'string' || elementType === 'number').toBe(true);
+    expect(this._instance._stringText).toBe(val);
     return this;
   },