[base] Introduce convenience typedefs for MockCallback

This change introduces the convenience typedefs base::MockOnceCallback,
base::MockRepeatingCallback, base::MockOnceClosure and
base::MockRepeatingClosure to base/test/mock_callback.h

Change-Id: I2db99b32e246b94da85805af666f9de93033ab33
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1674154Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672571}

base/test/mock_callback.h

@@ -8,7 +8,9 @@
 
 // Analogous to GMock's built-in MockFunction, but for base::Callback instead of
 // std::function. It takes the full callback type as a parameter, so that it can
-// support both OnceCallback and RepeatingCallback.
+// support both OnceCallback and RepeatingCallback. Furthermore, this file
+// defines convenience typedefs in the form of MockOnceCallback<Signature>,
+// MockRepeatingCallback<Signature>, MockOnceClosure and MockRepeatingClosure.
 //
 // Use:
 //   using FooCallback = base::RepeatingCallback<int(std::string)>;
@@ -19,6 +21,15 @@
 //     Foo(callback.Get());
 //   }
 //
+// Or equivalently:
+//
+//   TEST(FooTest, RunsCallbackWithBarArgument) {
+//     base::MockRepeatingCallback<int(std::string)> callback;
+//     EXPECT_CALL(callback, Run("bar")).WillOnce(Return(1));
+//     Foo(callback.Get());
+//   }
+//
+//
 // Can be used with StrictMock and NiceMock. Caller must ensure that it outlives
 // any base::Callback obtained from it.
 
@@ -37,6 +48,14 @@ namespace base {
 template <typename F>
 class MockCallback;
 
+template <typename Signature>
+using MockOnceCallback = MockCallback<OnceCallback<Signature>>;
+template <typename Signature>
+using MockRepeatingCallback = MockCallback<RepeatingCallback<Signature>>;
+
+using MockOnceClosure = MockCallback<OnceClosure>;
+using MockRepeatingClosure = MockCallback<RepeatingClosure>;
+
 template <typename R>
 class MockCallback<RepeatingCallback<R()>> {
  public:

base/test/mock_callback.h.pump

@@ -14,7 +14,9 @@ $$
 
 // Analogous to GMock's built-in MockFunction, but for base::Callback instead of
 // std::function. It takes the full callback type as a parameter, so that it can
-// support both OnceCallback and RepeatingCallback.
+// support both OnceCallback and RepeatingCallback. Furthermore, this file
+// defines convenience typedefs in the form of MockOnceCallback<Signature>,
+// MockRepeatingCallback<Signature>, MockOnceClosure and MockRepeatingClosure.
 //
 // Use:
 //   using FooCallback = base::RepeatingCallback<int(std::string)>;
@@ -25,6 +27,15 @@ $$
 //     Foo(callback.Get());
 //   }
 //
+// Or equivalently:
+//
+//   TEST(FooTest, RunsCallbackWithBarArgument) {
+//     base::MockRepeatingCallback<int(std::string)> callback;
+//     EXPECT_CALL(callback, Run("bar")).WillOnce(Return(1));
+//     Foo(callback.Get());
+//   }
+//
+//
 // Can be used with StrictMock and NiceMock. Caller must ensure that it outlives
 // any base::Callback obtained from it.
 
@@ -43,6 +54,14 @@ namespace base {
 template <typename F>
 class MockCallback;
 
+template <typename Signature>
+using MockOnceCallback = MockCallback<OnceCallback<Signature>>;
+template <typename Signature>
+using MockRepeatingCallback = MockCallback<RepeatingCallback<Signature>>;
+
+using MockOnceClosure = MockCallback<OnceClosure>;
+using MockRepeatingClosure = MockCallback<RepeatingClosure>;
+
 $range i 0..MAX_ARITY
 $for i [[
 $range j 1..i

base/test/mock_callback_unittest.cc

@@ -56,5 +56,26 @@ TEST(MockCallbackTest, WithArgsOnce) {
   EXPECT_EQ(42, std::move(two_int_callback).Run(1, 2));
 }
 
+TEST(MockCallbackTest, Typedefs) {
+  static_assert(std::is_same<MockCallback<RepeatingCallback<int()>>,
+                             MockRepeatingCallback<int()>>::value,
+                "Repeating typedef differs for zero args");
+  static_assert(std::is_same<MockCallback<RepeatingCallback<int(int, int)>>,
+                             MockRepeatingCallback<int(int, int)>>::value,
+                "Repeating typedef differs for multiple args");
+  static_assert(std::is_same<MockCallback<RepeatingCallback<void()>>,
+                             MockRepeatingClosure>::value,
+                "Repeating typedef differs for closure");
+  static_assert(std::is_same<MockCallback<OnceCallback<int()>>,
+                             MockOnceCallback<int()>>::value,
+                "Once typedef differs for zero args");
+  static_assert(std::is_same<MockCallback<OnceCallback<int(int, int)>>,
+                             MockOnceCallback<int(int, int)>>::value,
+                "Once typedef differs for multiple args");
+  static_assert(std::is_same<MockCallback<RepeatingCallback<void()>>,
+                             MockRepeatingClosure>::value,
+                "Once typedef differs for closure");
+}
+
 }  // namespace
 }  // namespace base