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author | Aaron Jacobs <jacobsa@google.com> | 2022-05-10 20:08:19 -0700 |
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committer | Copybara-Service <copybara-worker@google.com> | 2022-05-10 20:08:51 -0700 |
commit | 6386897feb0a3f4fbe104fe1fa4570ec8158d9e5 (patch) | |
tree | cb6d08bbb74311f40fb3784b50c60b8478ee0ab6 | |
parent | bda85449f48f2d80a494c8c07766b6aba3170f3b (diff) | |
download | googletest-6386897feb0a3f4fbe104fe1fa4570ec8158d9e5.zip googletest-6386897feb0a3f4fbe104fe1fa4570ec8158d9e5.tar.gz googletest-6386897feb0a3f4fbe104fe1fa4570ec8158d9e5.tar.bz2 |
gmock-actions: make OnceAction public.
So that it can be referenced in conversion operators for actions that need to
know the concrete return type.
PiperOrigin-RevId: 447889344
Change-Id: I643d3298bc8effd08741282a956c221f9d67d378
-rw-r--r-- | docs/gmock_cook_book.md | 63 | ||||
-rw-r--r-- | googlemock/include/gmock/gmock-actions.h | 14 | ||||
-rw-r--r-- | googlemock/test/gmock-actions_test.cc | 2 |
3 files changed, 59 insertions, 20 deletions
diff --git a/docs/gmock_cook_book.md b/docs/gmock_cook_book.md index bf52fa8..b6abffa 100644 --- a/docs/gmock_cook_book.md +++ b/docs/gmock_cook_book.md @@ -3812,22 +3812,19 @@ Cardinality EvenNumber() { .Times(EvenNumber()); ``` -### Writing New Actions Quickly {#QuickNewActions} +### Writing New Actions {#QuickNewActions} If the built-in actions don't work for you, you can easily define your own one. -Just define a functor class with a (possibly templated) call operator, matching -the signature of your action. +All you need is a call operator with a signature compatible with the mocked +function. So you can use a lambda: -```cpp -struct Increment { - template <typename T> - T operator()(T* arg) { - return ++(*arg); - } -} +``` +MockFunction<int(int)> mock; +EXPECT_CALL(mock, Call).WillOnce([](const int input) { return input * 7; }); +EXPECT_EQ(14, mock.AsStdFunction()(2)); ``` -The same approach works with stateful functors (or any callable, really): +Or a struct with a call operator (even a templated one): ``` struct MultiplyBy { @@ -3835,12 +3832,54 @@ struct MultiplyBy { T operator()(T arg) { return arg * multiplier; } int multiplier; -} +}; // Then use: // EXPECT_CALL(...).WillOnce(MultiplyBy{7}); ``` +It's also fine for the callable to take no arguments, ignoring the arguments +supplied to the mock function: + +``` +MockFunction<int(int)> mock; +EXPECT_CALL(mock, Call).WillOnce([] { return 17; }); +EXPECT_EQ(17, mock.AsStdFunction()(0)); +``` + +When used with `WillOnce`, the callable can assume it will be called at most +once and is allowed to be a move-only type: + +``` +// An action that contains move-only types and has an &&-qualified operator, +// demanding in the type system that it be called at most once. This can be +// used with WillOnce, but the compiler will reject it if handed to +// WillRepeatedly. +struct MoveOnlyAction { + std::unique_ptr<int> move_only_state; + std::unique_ptr<int> operator()() && { return std::move(move_only_state); } +}; + +MockFunction<std::unique_ptr<int>()> mock; +EXPECT_CALL(mock, Call).WillOnce(MoveOnlyAction{std::make_unique<int>(17)}); +EXPECT_THAT(mock.AsStdFunction()(), Pointee(Eq(17))); +``` + +More generally, to use with a mock function whose signature is `R(Args...)` the +object can be anything convertible to `OnceAction<R(Args...)>` or +`Action<R(Args...)`>. The difference between the two is that `OnceAction` has +weaker requirements (`Action` requires a copy-constructible input that can be +called repeatedly whereas `OnceAction` requires only move-constructible and +supports `&&`-qualified call operators), but can be used only with `WillOnce`. +`OnceAction` is typically relevant only when supporting move-only types or +actions that want a type-system guarantee that they will be called at most once. + +Typically the `OnceAction` and `Action` templates need not be referenced +directly in your actions: a struct or class with a call operator is sufficient, +as in the examples above. But fancier polymorphic actions that need to know the +specific return type of the mock function can define templated conversion +operators to make that possible. See `gmock-actions.h` for examples. + #### Legacy macro-based Actions Before C++11, the functor-based actions were not supported; the old way of diff --git a/googlemock/include/gmock/gmock-actions.h b/googlemock/include/gmock/gmock-actions.h index c83a99a..e022c12 100644 --- a/googlemock/include/gmock/gmock-actions.h +++ b/googlemock/include/gmock/gmock-actions.h @@ -322,16 +322,18 @@ struct is_callable_r_impl<void_t<call_result_t<F, Args...>>, R, F, Args...> template <typename R, typename F, typename... Args> using is_callable_r = is_callable_r_impl<void, R, F, Args...>; +} // namespace internal + // Specialized for function types below. template <typename F> class OnceAction; // An action that can only be used once. // -// This is what is accepted by WillOnce, which doesn't require the underlying -// action to be copy-constructible (only move-constructible), and promises to -// invoke it as an rvalue reference. This allows the action to work with -// move-only types like std::move_only_function in a type-safe manner. +// This is accepted by WillOnce, which doesn't require the underlying action to +// be copy-constructible (only move-constructible), and promises to invoke it as +// an rvalue reference. This allows the action to work with move-only types like +// std::move_only_function in a type-safe manner. // // For example: // @@ -501,8 +503,6 @@ class OnceAction<Result(Args...)> final { std::function<Result(Args...)> function_; }; -} // namespace internal - // When an unexpected function call is encountered, Google Mock will // let it return a default value if the user has specified one for its // return type, or if the return type has a built-in default value; @@ -742,7 +742,7 @@ class Action<R(Args...)> { // An action can be used as a OnceAction, since it's obviously safe to call it // once. - operator internal::OnceAction<F>() const { // NOLINT + operator OnceAction<F>() const { // NOLINT // Return a OnceAction-compatible callable that calls Perform with the // arguments it is provided. We could instead just return fun_, but then // we'd need to handle the IsDoDefault() case separately. diff --git a/googlemock/test/gmock-actions_test.cc b/googlemock/test/gmock-actions_test.cc index db112f1..7313b78 100644 --- a/googlemock/test/gmock-actions_test.cc +++ b/googlemock/test/gmock-actions_test.cc @@ -1920,7 +1920,7 @@ TEST(MockMethodTest, ActionSwallowsAllArguments) { struct ActionWithTemplatedConversionOperators { template <typename... Args> - operator internal::OnceAction<int(Args...)>() && { // NOLINT + operator OnceAction<int(Args...)>() && { // NOLINT return [] { return 17; }; } |