Add test for patching externally rendered DOM where a key moves up in the DOM on the first patch.

Author: Sepand Parhami

.babelrc

@@ -4,5 +4,6 @@
     "transform-es2015-arrow-functions",
     "transform-es2015-block-scoping",
     "transform-es2015-computed-properties",
+    "transform-es2015-template-literals"
   ]
 }

package.json

@@ -25,9 +25,10 @@
     "babel": "^6.5.2",
     "babel-plugin-check-es2015-constants": "^6.3.13",
     "babel-plugin-transform-es2015-arrow-functions": "^6.5.2",
+    "babel-plugin-transform-es2015-block-scoping": "^6.5.0",
     "babel-plugin-transform-es2015-computed-properties": "^6.5.2",
+    "babel-plugin-transform-es2015-template-literals": "^6.6.5",
     "babel-plugin-transform-inline-environment-variables": "^6.5.0",
-    "babel-plugin-transform-es2015-block-scoping": "^6.5.0",
     "chai": "^3.0.0",
     "del": "^2.0.2",
     "gulp": "^3.9.0",

test/functional/keyed_items.js

@@ -157,5 +157,22 @@ describe('rendering with keys', () => {
       patch(container, render, 'span');
     }).to.throw('Was expecting node with key "key" to be a span, not a div.');
   });
+
+  it('should preserve nodes already in the DOM', () => {
+    function render() {
+      elementVoid('div', 'key');
+      elementVoid('div');
+    }
+
+    container.innerHTML = `
+      <div></div>
+      <div key="key"><div>
+    `;
+
+    const keyedDiv = container.lastChild;
+    patch(container, render);
+
+    expect(container.firstChild).to.equal(keyedDiv);
+  });
 });