Adding mediator for Sign-in promo

ios/chrome/browser/ui/authentication/signin_promo_item_unittest.mm

Index: ios/chrome/browser/ui/authentication/signin_promo_item_unittest.mm
diff --git a/ios/chrome/browser/ui/authentication/signin_promo_item_unittest.mm b/ios/chrome/browser/ui/authentication/signin_promo_item_unittest.mm
new file mode 100644
index 0000000000000000000000000000000000000000..0bf1cd996b78598afe3535a85b2666a61c000e48
--- /dev/null
+++ b/ios/chrome/browser/ui/authentication/signin_promo_item_unittest.mm
@@ -0,0 +1,35 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "ios/chrome/browser/ui/authentication/signin_promo_item.h"
+
+#import "ios/chrome/browser/ui/authentication/signin_promo_view.h"
+#import "testing/gtest_mac.h"
+#import "third_party/ocmock/OCMock/OCMock.h"
+#include "third_party/ocmock/gtest_support.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+// Tests that SigninPromoItem creates and configures correctly SigninPromoCell.
+TEST(SigninPromoItemTest, ConfigureCell) {
+  id<SigninPromoViewConfigurator> configurator =
+      OCMStrictProtocolMock(@protocol(SigninPromoViewConfigurator));
+  SigninPromoItem* item = [[SigninPromoItem alloc] initWithType:0
+                                    signinPromoViewConfigurator:configurator];
+
+  id cell = [[[item cellClass] alloc] init];
+  ASSERT_TRUE([cell isMemberOfClass:[SigninPromoCell class]]);
+
+  SigninPromoCell* signInCell = cell;
+  EXPECT_NE(nil, signInCell.signinPromoView);
+  EXPECT_TRUE(
+      [signInCell.signinPromoView isMemberOfClass:[SigninPromoView class]]);
+  SigninPromoView* signinPromoView = signInCell.signinPromoView;
+  OCMExpect([configurator configureSigninPromoView:signinPromoView]);
+  [item configureCell:signInCell];
+  EXPECT_NE(nil, signinPromoView.textLabel.text);
+  EXPECT_OCMOCK_VERIFY(configurator);
+}