fix(@angular-devkit/schematics): move rule with identity is a noop

Author: clydin

packages/angular_devkit/schematics/src/rules/move.ts

@@ -7,6 +7,7 @@
  */
 import { normalize } from '@angular-devkit/core';
 import { Rule } from '../engine/interface';
+import { noop } from './base';
 
 
 export function move(from: string, to?: string): Rule {
@@ -18,6 +19,10 @@ export function move(from: string, to?: string): Rule {
   const fromPath = normalize('/' + from);
   const toPath = normalize('/' + to);
 
+  if (fromPath === toPath) {
+    return noop;
+  }
+
   return tree => tree.visit(path => {
     if (path.startsWith(fromPath)) {
       tree.rename(path, toPath + '/' + path.substr(fromPath.length));

packages/angular_devkit/schematics/src/rules/move_spec.ts

@@ -48,4 +48,20 @@ describe('move', () => {
       })
       .then(done, done.fail);
   });
+
+  it('becomes a noop with identical from and to', done => {
+    const tree = new HostTree();
+    tree.create('a/b/file1', 'hello world');
+    tree.create('a/b/file2', 'hello world');
+    tree.create('a/c/file3', 'hello world');
+
+    callRule(move(''), observableOf(tree), context)
+      .toPromise()
+      .then(result => {
+        expect(result.exists('a/b/file1')).toBe(true);
+        expect(result.exists('a/b/file2')).toBe(true);
+        expect(result.exists('a/c/file3')).toBe(true);
+      })
+      .then(done, done.fail);
+  });
 });