fix(subheader): fix hidden directives inside of sticky clone.

* Currently the subheader was not working properly with `ng-if`'s inside of its content.
  This was caused by a wrong recompile of the already compiled transcluded clone.

* This commit also fixes the meaningless / useless tests.
   Before we never imported the `subheader` module into its tests.
   Also we never tested the $mdSticky service together with the subheader, because
   we had a really ugly mock for the `$mdSticky` service, which just tested the call arguments.

Fixes #8500. Closes #8504.

Closes #8505

src/components/subheader/subheader.js

@@ -77,17 +77,17 @@ function MdSubheaderDirective($mdSticky, $compile, $mdTheming, $mdUtil) {
           // compiled clone below will only be a comment tag (since they replace their elements with
           // a comment) which cannot be properly passed to the $mdSticky; so we wrap it in our own
           // DIV to ensure we have something $mdSticky can use
-          var wrapperHtml = '<div class="_md-subheader-wrapper">' + outerHTML + '</div>';
-          var stickyClone = $compile(wrapperHtml)(scope);
+          var wrapper = angular.element('<div class="_md-subheader-wrapper">' + outerHTML + '</div>');
 
-          // Append the sticky
-          $mdSticky(scope, element, stickyClone);
+          // Immediately append our transcluded clone into the wrapper.
+          // We don't have to recompile the element again, because the clone is already
+          // compiled in it's transclusion scope. If we recompile the outerHTML of the new clone, we would lose
+          // our ngIf's and other previous registered bindings / properties.
+          getContent(wrapper).append(clone);
 
-          // Delay initialization until after any `ng-if`/`ng-repeat`/etc has finished before
-          // attempting to create the clone
-          $mdUtil.nextTick(function() {
-            getContent(stickyClone).append(clone);
-          });
+          // Make the element sticky and provide the stickyClone our self, to avoid recompilation of the subheader
+          // element.
+          $mdSticky(scope, element, wrapper);
         });
       }
     }

src/components/subheader/subheader.spec.js

@@ -1,35 +1,31 @@
 describe('mdSubheader', function() {
-  var $mdStickyMock,
-      basicHtml = '<md-subheader>Hello world!</md-header>',
-      pageScope, element, controller;
-
+  var BASIC_SUBHEADER = '<md-subheader>Hello world!</md-subheader>';
+  var pageScope, element, controller, contentElement;
   var $rootScope, $timeout, $exceptionHandler;
 
-  beforeEach(module('material.components.subheader', function($provide) {
-    $mdStickyMock = function() {
-      $mdStickyMock.args = Array.prototype.slice.call(arguments);
-    };
-    $provide.value('$mdSticky', $mdStickyMock);
-  }));
+  beforeEach(module('material.components.subheader'));
 
-  beforeEach(inject(function(_$rootScope_, _$timeout_, _$exceptionHandler_) {
-    $rootScope = _$rootScope_;
-    $timeout = _$timeout_;
-    $exceptionHandler = _$exceptionHandler_;
+  beforeEach(inject(function($injector) {
+    $rootScope = $injector.get('$rootScope');
+    $timeout = $injector.get('$timeout');
+    $exceptionHandler = $injector.get('$exceptionHandler');
   }));
 
 
   it('should have `._md` class indicator', inject(function() {
-    build('<div><md-subheader>Hello {{ to }}!</md-subheader></div>');
-    pageScope.to = 'world';
-    pageScope.$digest();
+    build(BASIC_SUBHEADER);
 
-    expect(element.children().hasClass('_md')).toBe(true);
+    expect(element.hasClass('_md')).toBe(true);
   }));
 
 
   it('preserves content', function() {
-    build('<div><md-subheader>Hello {{ to }}!</md-subheader></div>');
+    build(
+      '<div>' +
+        '<md-subheader>Hello {{ to }}!</md-subheader>' +
+      '</div>'
+    );
+
     pageScope.to = 'world';
     pageScope.$digest();
 
@@ -39,23 +35,22 @@ describe('mdSubheader', function() {
   });
 
   it('implements $mdSticky', function() {
-    build(basicHtml);
+    build(BASIC_SUBHEADER);
 
-    expect($mdStickyMock.args[0]).toBe(pageScope);
+    var cloneScope = element.scope();
+
+    expect(cloneScope).toBe(pageScope);
   });
 
   it('applies the theme to the header and clone', function() {
-    build('<div md-theme="somethingElse">' + basicHtml + '</div>');
-
-    // Grab the real element
-    var element = $mdStickyMock.args[1];
+    build('<div md-theme="somethingElse">' + BASIC_SUBHEADER + '</div>');
 
     // The subheader now wraps the clone in a DIV in case of ng-if usage, so we have to search for
     // the proper element.
-    var clone = angular.element($mdStickyMock.args[2][0].querySelector('.md-subheader'));
+    var clone = getCloneElement();
 
-    expect(element.hasClass('md-somethingElse-theme')).toBe(true);
-    expect(clone.hasClass('md-somethingElse-theme')).toBe(true);
+    expect(getSubheader().classList).toContain('md-somethingElse-theme');
+    expect(getSubheader(clone).classList).toContain('md-somethingElse-theme');
   });
 
   it('applies the proper scope to the clone', function() {
@@ -64,11 +59,10 @@ describe('mdSubheader', function() {
     pageScope.to = 'world';
     pageScope.$apply();
 
-    var element = $mdStickyMock.args[1];
-    var clone = $mdStickyMock.args[2];
+    var clone = getCloneElement();
 
-    expect(element.text().trim()).toEqual('Hello world!');
-    expect(clone.text().trim()).toEqual('Hello world!');
+    expect(getSubheader().textContent.trim()).toEqual('Hello world!');
+    expect(getSubheader(clone).textContent.trim()).toEqual('Hello world!');
   });
 
   it('supports ng-if', function() {
@@ -78,6 +72,39 @@ describe('mdSubheader', function() {
     expect(element[0].querySelectorAll('.md-subheader').length).toEqual(1);
   });
 
+  it('should support ng-if inside of stickyClone', function() {
+    build(
+      '<div>' +
+        '<md-subheader>' +
+          'Foo' +
+          '<span ng-if="isBar">Bar</span>' +
+        '</md-subheader>' +
+      '</div>'
+    );
+
+    var clone = getCloneElement()[0];
+
+    expect(clone.textContent.trim()).toBe('Foo');
+
+    pageScope.$apply('isBar = true');
+
+    expect(clone.textContent.trim()).toBe('FooBar');
+  });
+
+  it('should work with a ng-if directive inside of the stickyClone', function() {
+    build(
+      '<div>' +
+        '<md-subheader>' +
+          '<span ng-repeat="item in [0, 1, 2, 3]">{{ item }}</span>' +
+        '</md-subheader>' +
+      '</div>'
+    );
+
+    var cloneContent = getCloneElement()[0].querySelector('._md-subheader-content');
+
+    expect(cloneContent.children.length).toBe(4);
+  });
+
   it('supports ng-repeat', function() {
     build('<div><md-subheader ng-repeat="i in [1,2,3]">Test {{i}}</md-subheader></div>');
 
@@ -86,13 +113,38 @@ describe('mdSubheader', function() {
   });
 
   function build(template) {
-    inject(function($compile) {
+    inject(function($compile, $timeout) {
       pageScope = $rootScope.$new();
-      element = $compile(template)(pageScope);
+
+      contentElement = $compile('<md-content>' + template + '</md-content>')(pageScope);
+
+      // Flush the timeout, which prepends the sticky clone to the md-content.
+      $timeout.flush();
+
+      // When the contentElement only has only one children then the current
+      // browser supports sticky elements natively.
+      if (contentElement.children().length === 1) {
+        element = getCloneElement();
+      } else {
+        // When the browser doesn't support sticky elements natively we will have a sticky clone.
+        // The sticky clone element will be always prepended, which means that we have to use the child
+        // at the second position.
+        element = contentElement.children().eq(1);
+      }
+
       controller = element.controller('mdSubheader');
 
       pageScope.$apply();
       $timeout.flush();
     });
   }
+
+  function getSubheader(el) {
+    return (el || element)[0].querySelector('.md-subheader');
+  }
+
+  function getCloneElement() {
+    // The clone element will be always prepended, which means that we have to get the child at index zero.
+    return contentElement.children().eq(0);
+  }
 });