3 <!-- GOOGLETEST_CM0019 DO NOT DELETE -->
5 <!-- GOOGLETEST_CM0033 DO NOT DELETE -->
7 ### Defining a Mock Class
9 #### Mocking a Normal Class {#MockClass}
17 virtual int GetSize() const = 0;
18 virtual string Describe(const char* name) = 0;
19 virtual string Describe(int type) = 0;
20 virtual bool Process(Bar elem, int count) = 0;
24 (note that `~Foo()` **must** be virtual) we can define its mock as
27 #include "gmock/gmock.h"
29 class MockFoo : public Foo {
31 MOCK_METHOD(int, GetSize, (), (const, override));
32 MOCK_METHOD(string, Describe, (const char* name), (override));
33 MOCK_METHOD(string, Describe, (int type), (override));
34 MOCK_METHOD(bool, Process, (Bar elem, int count), (override));
38 To create a "nice" mock, which ignores all uninteresting calls, a "naggy" mock,
39 which warns on all uninteresting calls, or a "strict" mock, which treats them as
43 using ::testing::NiceMock;
44 using ::testing::NaggyMock;
45 using ::testing::StrictMock;
47 NiceMock<MockFoo> nice_foo; // The type is a subclass of MockFoo.
48 NaggyMock<MockFoo> naggy_foo; // The type is a subclass of MockFoo.
49 StrictMock<MockFoo> strict_foo; // The type is a subclass of MockFoo.
52 **Note:** A mock object is currently naggy by default. We may make it nice by
53 default in the future.
55 #### Mocking a Class Template {#MockTemplate}
57 Class templates can be mocked just like any class.
62 template <typename Elem>
63 class StackInterface {
65 virtual ~StackInterface();
66 virtual int GetSize() const = 0;
67 virtual void Push(const Elem& x) = 0;
71 (note that all member functions that are mocked, including `~StackInterface()`
75 template <typename Elem>
76 class MockStack : public StackInterface<Elem> {
78 MOCK_METHOD(int, GetSize, (), (const, override));
79 MOCK_METHOD(void, Push, (const Elem& x), (override));
83 #### Specifying Calling Conventions for Mock Functions
85 If your mock function doesn't use the default calling convention, you can
86 specify it by adding `Calltype(convention)` to `MOCK_METHOD`'s 4th parameter.
90 MOCK_METHOD(bool, Foo, (int n), (Calltype(STDMETHODCALLTYPE)));
91 MOCK_METHOD(int, Bar, (double x, double y),
92 (const, Calltype(STDMETHODCALLTYPE)));
95 where `STDMETHODCALLTYPE` is defined by `<objbase.h>` on Windows.
97 ### Using Mocks in Tests {#UsingMocks}
99 The typical work flow is:
101 1. Import the gMock names you need to use. All gMock symbols are in the
102 `testing` namespace unless they are macros or otherwise noted.
103 2. Create the mock objects.
104 3. Optionally, set the default actions of the mock objects.
105 4. Set your expectations on the mock objects (How will they be called? What
107 5. Exercise code that uses the mock objects; if necessary, check the result
108 using googletest assertions.
109 6. When a mock object is destructed, gMock automatically verifies that all
110 expectations on it have been satisfied.
115 using ::testing::Return; // #1
117 TEST(BarTest, DoesThis) {
120 ON_CALL(foo, GetSize()) // #3
121 .WillByDefault(Return(1));
122 // ... other default actions ...
124 EXPECT_CALL(foo, Describe(5)) // #4
126 .WillRepeatedly(Return("Category 5"));
127 // ... other expectations ...
129 EXPECT_EQ("good", MyProductionFunction(&foo)); // #5
133 ### Setting Default Actions {#OnCall}
135 gMock has a **built-in default action** for any function that returns `void`,
136 `bool`, a numeric value, or a pointer. In C++11, it will additionally returns
137 the default-constructed value, if one exists for the given type.
139 To customize the default action for functions with return type *`T`*:
142 using ::testing::DefaultValue;
144 // Sets the default value to be returned. T must be CopyConstructible.
145 DefaultValue<T>::Set(value);
146 // Sets a factory. Will be invoked on demand. T must be MoveConstructible.
148 DefaultValue<T>::SetFactory(&MakeT);
149 // ... use the mocks ...
150 // Resets the default value.
151 DefaultValue<T>::Clear();
157 // Sets the default action for return type std::unique_ptr<Buzz> to
158 // creating a new Buzz every time.
159 DefaultValue<std::unique_ptr<Buzz>>::SetFactory(
160 [] { return MakeUnique<Buzz>(AccessLevel::kInternal); });
162 // When this fires, the default action of MakeBuzz() will run, which
163 // will return a new Buzz object.
164 EXPECT_CALL(mock_buzzer_, MakeBuzz("hello")).Times(AnyNumber());
166 auto buzz1 = mock_buzzer_.MakeBuzz("hello");
167 auto buzz2 = mock_buzzer_.MakeBuzz("hello");
168 EXPECT_NE(nullptr, buzz1);
169 EXPECT_NE(nullptr, buzz2);
170 EXPECT_NE(buzz1, buzz2);
172 // Resets the default action for return type std::unique_ptr<Buzz>,
173 // to avoid interfere with other tests.
174 DefaultValue<std::unique_ptr<Buzz>>::Clear();
177 To customize the default action for a particular method of a specific mock
178 object, use `ON_CALL()`. `ON_CALL()` has a similar syntax to `EXPECT_CALL()`,
179 but it is used for setting default behaviors (when you do not require that the
180 mock method is called). See [here](cook_book.md#UseOnCall) for a more detailed
184 ON_CALL(mock-object, method(matchers))
185 .With(multi-argument-matcher) ?
186 .WillByDefault(action);
189 ### Setting Expectations {#ExpectCall}
191 `EXPECT_CALL()` sets **expectations** on a mock method (How will it be called?
195 EXPECT_CALL(mock-object, method (matchers)?)
196 .With(multi-argument-matcher) ?
197 .Times(cardinality) ?
198 .InSequence(sequences) *
199 .After(expectations) *
201 .WillRepeatedly(action) ?
202 .RetiresOnSaturation(); ?
205 For each item above, `?` means it can be used at most once, while `*` means it
206 can be used any number of times.
208 In order to pass, `EXPECT_CALL` must be used before the calls are actually made.
210 The `(matchers)` is a comma-separated list of matchers that correspond to each
211 of the arguments of `method`, and sets the expectation only for calls of
212 `method` that matches all of the matchers.
214 If `(matchers)` is omitted, the expectation is the same as if the matchers were
215 set to anything matchers (for example, `(_, _, _, _)` for a four-arg method).
217 If `Times()` is omitted, the cardinality is assumed to be:
219 * `Times(1)` when there is neither `WillOnce()` nor `WillRepeatedly()`;
220 * `Times(n)` when there are `n` `WillOnce()`s but no `WillRepeatedly()`, where
222 * `Times(AtLeast(n))` when there are `n` `WillOnce()`s and a
223 `WillRepeatedly()`, where `n` >= 0.
225 A method with no `EXPECT_CALL()` is free to be invoked *any number of times*,
226 and the default action will be taken each time.
228 ### Matchers {#MatcherList}
230 <!-- GOOGLETEST_CM0020 DO NOT DELETE -->
232 A **matcher** matches a *single* argument. You can use it inside `ON_CALL()` or
233 `EXPECT_CALL()`, or use it to validate a value directly using two macros:
235 <!-- mdformat off(github rendering does not support multiline tables) -->
236 | Macro | Description |
237 | :----------------------------------- | :------------------------------------ |
238 | `EXPECT_THAT(actual_value, matcher)` | Asserts that `actual_value` matches `matcher`. |
239 | `ASSERT_THAT(actual_value, matcher)` | The same as `EXPECT_THAT(actual_value, matcher)`, except that it generates a **fatal** failure. |
242 Built-in matchers (where `argument` is the function argument, e.g.
243 `actual_value` in the example above, or when used in the context of
244 `EXPECT_CALL(mock_object, method(matchers))`, the arguments of `method`) are
245 divided into several categories:
249 Matcher | Description
250 :-------------------------- | :-----------------------------------------------
251 `_` | `argument` can be any value of the correct type.
252 `A<type>()` or `An<type>()` | `argument` can be any value of type `type`.
254 #### Generic Comparison
256 <!-- mdformat off(no multiline tables) -->
257 | Matcher | Description |
258 | :--------------------- | :-------------------------------------------------- |
259 | `Eq(value)` or `value` | `argument == value` |
260 | `Ge(value)` | `argument >= value` |
261 | `Gt(value)` | `argument > value` |
262 | `Le(value)` | `argument <= value` |
263 | `Lt(value)` | `argument < value` |
264 | `Ne(value)` | `argument != value` |
265 | `IsFalse()` | `argument` evaluates to `false` in a Boolean context. |
266 | `IsTrue()` | `argument` evaluates to `true` in a Boolean context. |
267 | `IsNull()` | `argument` is a `NULL` pointer (raw or smart). |
268 | `NotNull()` | `argument` is a non-null pointer (raw or smart). |
269 | `Optional(m)` | `argument` is `optional<>` that contains a value matching `m`. |
270 | `VariantWith<T>(m)` | `argument` is `variant<>` that holds the alternative of type T with a value matching `m`. |
271 | `Ref(variable)` | `argument` is a reference to `variable`. |
272 | `TypedEq<type>(value)` | `argument` has type `type` and is equal to `value`. You may need to use this instead of `Eq(value)` when the mock function is overloaded. |
275 Except `Ref()`, these matchers make a *copy* of `value` in case it's modified or
276 destructed later. If the compiler complains that `value` doesn't have a public
277 copy constructor, try wrap it in `ByRef()`, e.g.
278 `Eq(ByRef(non_copyable_value))`. If you do that, make sure `non_copyable_value`
279 is not changed afterwards, or the meaning of your matcher will be changed.
281 #### Floating-Point Matchers {#FpMatchers}
283 <!-- mdformat off(no multiline tables) -->
284 | Matcher | Description |
285 | :------------------------------- | :--------------------------------- |
286 | `DoubleEq(a_double)` | `argument` is a `double` value approximately equal to `a_double`, treating two NaNs as unequal. |
287 | `FloatEq(a_float)` | `argument` is a `float` value approximately equal to `a_float`, treating two NaNs as unequal. |
288 | `NanSensitiveDoubleEq(a_double)` | `argument` is a `double` value approximately equal to `a_double`, treating two NaNs as equal. |
289 | `NanSensitiveFloatEq(a_float)` | `argument` is a `float` value approximately equal to `a_float`, treating two NaNs as equal. |
292 The above matchers use ULP-based comparison (the same as used in googletest).
293 They automatically pick a reasonable error bound based on the absolute value of
294 the expected value. `DoubleEq()` and `FloatEq()` conform to the IEEE standard,
295 which requires comparing two NaNs for equality to return false. The
296 `NanSensitive*` version instead treats two NaNs as equal, which is often what a
299 <!-- mdformat off(no multiline tables) -->
300 | Matcher | Description |
301 | :------------------------------------------------ | :----------------------- |
302 | `DoubleNear(a_double, max_abs_error)` | `argument` is a `double` value close to `a_double` (absolute error <= `max_abs_error`), treating two NaNs as unequal. |
303 | `FloatNear(a_float, max_abs_error)` | `argument` is a `float` value close to `a_float` (absolute error <= `max_abs_error`), treating two NaNs as unequal. |
304 | `NanSensitiveDoubleNear(a_double, max_abs_error)` | `argument` is a `double` value close to `a_double` (absolute error <= `max_abs_error`), treating two NaNs as equal. |
305 | `NanSensitiveFloatNear(a_float, max_abs_error)` | `argument` is a `float` value close to `a_float` (absolute error <= `max_abs_error`), treating two NaNs as equal. |
310 The `argument` can be either a C string or a C++ string object:
312 <!-- mdformat off(no multiline tables) -->
313 | Matcher | Description |
314 | :---------------------- | :------------------------------------------------- |
315 | `ContainsRegex(string)` | `argument` matches the given regular expression. |
316 | `EndsWith(suffix)` | `argument` ends with string `suffix`. |
317 | `HasSubstr(string)` | `argument` contains `string` as a sub-string. |
318 | `MatchesRegex(string)` | `argument` matches the given regular expression with the match starting at the first character and ending at the last character. |
319 | `StartsWith(prefix)` | `argument` starts with string `prefix`. |
320 | `StrCaseEq(string)` | `argument` is equal to `string`, ignoring case. |
321 | `StrCaseNe(string)` | `argument` is not equal to `string`, ignoring case. |
322 | `StrEq(string)` | `argument` is equal to `string`. |
323 | `StrNe(string)` | `argument` is not equal to `string`. |
326 `ContainsRegex()` and `MatchesRegex()` take ownership of the `RE` object. They
327 use the regular expression syntax defined
328 [here](../../googletest/docs/advanced.md#regular-expression-syntax).
329 `StrCaseEq()`, `StrCaseNe()`, `StrEq()`, and `StrNe()` work for wide strings as
332 #### Container Matchers
334 Most STL-style containers support `==`, so you can use `Eq(expected_container)`
335 or simply `expected_container` to match a container exactly. If you want to
336 write the elements in-line, match them more flexibly, or get more informative
337 messages, you can use:
339 <!-- mdformat off(no multiline tables) -->
340 | Matcher | Description |
341 | :---------------------------------------- | :------------------------------- |
342 | `BeginEndDistanceIs(m)` | `argument` is a container whose `begin()` and `end()` iterators are separated by a number of increments matching `m`. E.g. `BeginEndDistanceIs(2)` or `BeginEndDistanceIs(Lt(2))`. For containers that define a `size()` method, `SizeIs(m)` may be more efficient. |
343 | `ContainerEq(container)` | The same as `Eq(container)` except that the failure message also includes which elements are in one container but not the other. |
344 | `Contains(e)` | `argument` contains an element that matches `e`, which can be either a value or a matcher. |
345 | `Each(e)` | `argument` is a container where *every* element matches `e`, which can be either a value or a matcher. |
346 | `ElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, where the *i*-th element matches `ei`, which can be a value or a matcher. |
347 | `ElementsAreArray({e0, e1, ..., en})`, `ElementsAreArray(a_container)`, `ElementsAreArray(begin, end)`, `ElementsAreArray(array)`, or `ElementsAreArray(array, count)` | The same as `ElementsAre()` except that the expected element values/matchers come from an initializer list, STL-style container, iterator range, or C-style array. |
348 | `IsEmpty()` | `argument` is an empty container (`container.empty()`). |
349 | `IsSubsetOf({e0, e1, ..., en})`, `IsSubsetOf(a_container)`, `IsSubsetOf(begin, end)`, `IsSubsetOf(array)`, or `IsSubsetOf(array, count)` | `argument` matches `UnorderedElementsAre(x0, x1, ..., xk)` for some subset `{x0, x1, ..., xk}` of the expected matchers. |
350 | `IsSupersetOf({e0, e1, ..., en})`, `IsSupersetOf(a_container)`, `IsSupersetOf(begin, end)`, `IsSupersetOf(array)`, or `IsSupersetOf(array, count)` | Some subset of `argument` matches `UnorderedElementsAre(`expected matchers`)`. |
351 | `Pointwise(m, container)`, `Pointwise(m, {e0, e1, ..., en})` | `argument` contains the same number of elements as in `container`, and for all i, (the i-th element in `argument`, the i-th element in `container`) match `m`, which is a matcher on 2-tuples. E.g. `Pointwise(Le(), upper_bounds)` verifies that each element in `argument` doesn't exceed the corresponding element in `upper_bounds`. See more detail below. |
352 | `SizeIs(m)` | `argument` is a container whose size matches `m`. E.g. `SizeIs(2)` or `SizeIs(Lt(2))`. |
353 | `UnorderedElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, and under *some* permutation of the elements, each element matches an `ei` (for a different `i`), which can be a value or a matcher. |
354 | `UnorderedElementsAreArray({e0, e1, ..., en})`, `UnorderedElementsAreArray(a_container)`, `UnorderedElementsAreArray(begin, end)`, `UnorderedElementsAreArray(array)`, or `UnorderedElementsAreArray(array, count)` | The same as `UnorderedElementsAre()` except that the expected element values/matchers come from an initializer list, STL-style container, iterator range, or C-style array. |
355 | `UnorderedPointwise(m, container)`, `UnorderedPointwise(m, {e0, e1, ..., en})` | Like `Pointwise(m, container)`, but ignores the order of elements. |
356 | `WhenSorted(m)` | When `argument` is sorted using the `<` operator, it matches container matcher `m`. E.g. `WhenSorted(ElementsAre(1, 2, 3))` verifies that `argument` contains elements 1, 2, and 3, ignoring order. |
357 | `WhenSortedBy(comparator, m)` | The same as `WhenSorted(m)`, except that the given comparator instead of `<` is used to sort `argument`. E.g. `WhenSortedBy(std::greater(), ElementsAre(3, 2, 1))`. |
362 * These matchers can also match:
363 1. a native array passed by reference (e.g. in `Foo(const int (&a)[5])`),
365 2. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer,
366 int len)` -- see [Multi-argument Matchers](#MultiArgMatchers)).
367 * The array being matched may be multi-dimensional (i.e. its elements can be
369 * `m` in `Pointwise(m, ...)` should be a matcher for `::std::tuple<T, U>`
370 where `T` and `U` are the element type of the actual container and the
371 expected container, respectively. For example, to compare two `Foo`
372 containers where `Foo` doesn't support `operator==`, one might write:
377 return std::get<0>(arg).Equals(std::get<1>(arg));
380 EXPECT_THAT(actual_foos, Pointwise(FooEq(), expected_foos));
385 <!-- mdformat off(no multiline tables) -->
386 | Matcher | Description |
387 | :------------------------------ | :----------------------------------------- |
388 | `Field(&class::field, m)` | `argument.field` (or `argument->field` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_. |
389 | `Key(e)` | `argument.first` matches `e`, which can be either a value or a matcher. E.g. `Contains(Key(Le(5)))` can verify that a `map` contains a key `<= 5`. |
390 | `Pair(m1, m2)` | `argument` is an `std::pair` whose `first` field matches `m1` and `second` field matches `m2`. |
391 | `Property(&class::property, m)` | `argument.property()` (or `argument->property()` when `argument` is a plain pointer) matches matcher `m`, where `argument` is an object of type _class_. |
394 #### Matching the Result of a Function, Functor, or Callback
396 <!-- mdformat off(no multiline tables) -->
397 | Matcher | Description |
398 | :--------------- | :------------------------------------------------ |
399 | `ResultOf(f, m)` | `f(argument)` matches matcher `m`, where `f` is a function or functor. |
402 #### Pointer Matchers
404 <!-- mdformat off(no multiline tables) -->
405 | Matcher | Description |
406 | :------------------------ | :---------------------------------------------- |
407 | `Pointee(m)` | `argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`. |
408 | `WhenDynamicCastTo<T>(m)` | when `argument` is passed through `dynamic_cast<T>()`, it matches matcher `m`. |
411 <!-- GOOGLETEST_CM0026 DO NOT DELETE -->
413 <!-- GOOGLETEST_CM0027 DO NOT DELETE -->
415 #### Multi-argument Matchers {#MultiArgMatchers}
417 Technically, all matchers match a *single* value. A "multi-argument" matcher is
418 just one that matches a *tuple*. The following matchers can be used to match a
421 Matcher | Description
422 :------ | :----------
430 You can use the following selectors to pick a subset of the arguments (or
431 reorder them) to participate in the matching:
433 <!-- mdformat off(no multiline tables) -->
434 | Matcher | Description |
435 | :------------------------- | :---------------------------------------------- |
436 | `AllArgs(m)` | Equivalent to `m`. Useful as syntactic sugar in `.With(AllArgs(m))`. |
437 | `Args<N1, N2, ..., Nk>(m)` | The tuple of the `k` selected (using 0-based indices) arguments matches `m`, e.g. `Args<1, 2>(Eq())`. |
440 #### Composite Matchers
442 You can make a matcher from one or more other matchers:
444 <!-- mdformat off(no multiline tables) -->
445 | Matcher | Description |
446 | :------------------------------- | :-------------------------------------- |
447 | `AllOf(m1, m2, ..., mn)` | `argument` matches all of the matchers `m1` to `mn`. |
448 | `AllOfArray({m0, m1, ..., mn})`, `AllOfArray(a_container)`, `AllOfArray(begin, end)`, `AllOfArray(array)`, or `AllOfArray(array, count)` | The same as `AllOf()` except that the matchers come from an initializer list, STL-style container, iterator range, or C-style array. |
449 | `AnyOf(m1, m2, ..., mn)` | `argument` matches at least one of the matchers `m1` to `mn`. |
450 | `AnyOfArray({m0, m1, ..., mn})`, `AnyOfArray(a_container)`, `AnyOfArray(begin, end)`, `AnyOfArray(array)`, or `AnyOfArray(array, count)` | The same as `AnyOf()` except that the matchers come from an initializer list, STL-style container, iterator range, or C-style array. |
451 | `Not(m)` | `argument` doesn't match matcher `m`. |
454 <!-- GOOGLETEST_CM0028 DO NOT DELETE -->
456 #### Adapters for Matchers
458 <!-- mdformat off(no multiline tables) -->
459 | Matcher | Description |
460 | :---------------------- | :------------------------------------ |
461 | `MatcherCast<T>(m)` | casts matcher `m` to type `Matcher<T>`. |
462 | `SafeMatcherCast<T>(m)` | [safely casts](cook_book.md#casting-matchers) matcher `m` to type `Matcher<T>`. |
463 | `Truly(predicate)` | `predicate(argument)` returns something considered by C++ to be true, where `predicate` is a function or functor. |
466 `AddressSatisfies(callback)` and `Truly(callback)` take ownership of `callback`,
467 which must be a permanent callback.
469 #### Using Matchers as Predicates {#MatchersAsPredicatesCheat}
471 <!-- mdformat off(no multiline tables) -->
472 | Matcher | Description |
473 | :---------------------------- | :------------------------------------------ |
474 | `Matches(m)(value)` | evaluates to `true` if `value` matches `m`. You can use `Matches(m)` alone as a unary functor. |
475 | `ExplainMatchResult(m, value, result_listener)` | evaluates to `true` if `value` matches `m`, explaining the result to `result_listener`. |
476 | `Value(value, m)` | evaluates to `true` if `value` matches `m`. |
479 #### Defining Matchers
481 <!-- mdformat off(no multiline tables) -->
482 | Matcher | Description |
483 | :----------------------------------- | :------------------------------------ |
484 | `MATCHER(IsEven, "") { return (arg % 2) == 0; }` | Defines a matcher `IsEven()` to match an even number. |
485 | `MATCHER_P(IsDivisibleBy, n, "") { *result_listener << "where the remainder is " << (arg % n); return (arg % n) == 0; }` | Defines a macher `IsDivisibleBy(n)` to match a number divisible by `n`. |
486 | `MATCHER_P2(IsBetween, a, b, std::string(negation ? "isn't" : "is") + " between " + PrintToString(a) + " and " + PrintToString(b)) { return a <= arg && arg <= b; }` | Defines a matcher `IsBetween(a, b)` to match a value in the range [`a`, `b`]. |
491 1. The `MATCHER*` macros cannot be used inside a function or class.
492 2. The matcher body must be *purely functional* (i.e. it cannot have any side
493 effect, and the result must not depend on anything other than the value
494 being matched and the matcher parameters).
495 3. You can use `PrintToString(x)` to convert a value `x` of any type to a
498 ### Actions {#ActionList}
500 **Actions** specify what a mock function should do when invoked.
502 #### Returning a Value
504 <!-- mdformat off(no multiline tables) -->
506 | :-------------------------- | :-------------------------------------------- |
507 | `Return()` | Return from a `void` mock function. |
508 | `Return(value)` | Return `value`. If the type of `value` is different to the mock function's return type, `value` is converted to the latter type <i>at the time the expectation is set</i>, not when the action is executed. |
509 | `ReturnArg<N>()` | Return the `N`-th (0-based) argument. |
510 | `ReturnNew<T>(a1, ..., ak)` | Return `new T(a1, ..., ak)`; a different object is created each time. |
511 | `ReturnNull()` | Return a null pointer. |
512 | `ReturnPointee(ptr)` | Return the value pointed to by `ptr`. |
513 | `ReturnRef(variable)` | Return a reference to `variable`. |
514 | `ReturnRefOfCopy(value)` | Return a reference to a copy of `value`; the copy lives as long as the action. |
519 <!-- mdformat off(no multiline tables) -->
521 | :--------------------------------- | :-------------------------------------- |
522 | `Assign(&variable, value)` | Assign `value` to variable. |
523 | `DeleteArg<N>()` | Delete the `N`-th (0-based) argument, which must be a pointer. |
524 | `SaveArg<N>(pointer)` | Save the `N`-th (0-based) argument to `*pointer`. |
525 | `SaveArgPointee<N>(pointer)` | Save the value pointed to by the `N`-th (0-based) argument to `*pointer`. |
526 | `SetArgReferee<N>(value)` | Assign value to the variable referenced by the `N`-th (0-based) argument. |
527 | `SetArgPointee<N>(value)` | Assign `value` to the variable pointed by the `N`-th (0-based) argument. |
528 | `SetArgumentPointee<N>(value)` | Same as `SetArgPointee<N>(value)`. Deprecated. Will be removed in v1.7.0. |
529 | `SetArrayArgument<N>(first, last)` | Copies the elements in source range [`first`, `last`) to the array pointed to by the `N`-th (0-based) argument, which can be either a pointer or an iterator. The action does not take ownership of the elements in the source range. |
530 | `SetErrnoAndReturn(error, value)` | Set `errno` to `error` and return `value`. |
531 | `Throw(exception)` | Throws the given exception, which can be any copyable value. Available since v1.1.0. |
534 #### Using a Function, Functor, or Lambda as an Action
536 In the following, by "callable" we mean a free function, `std::function`,
539 <!-- mdformat off(no multiline tables) -->
541 | :---------------------------------- | :------------------------------------- |
542 | `f` | Invoke f with the arguments passed to the mock function, where f is a callable. |
543 | `Invoke(f)` | Invoke `f` with the arguments passed to the mock function, where `f` can be a global/static function or a functor. |
544 | `Invoke(object_pointer, &class::method)` | Invoke the method on the object with the arguments passed to the mock function. |
545 | `InvokeWithoutArgs(f)` | Invoke `f`, which can be a global/static function or a functor. `f` must take no arguments. |
546 | `InvokeWithoutArgs(object_pointer, &class::method)` | Invoke the method on the object, which takes no arguments. |
547 | `InvokeArgument<N>(arg1, arg2, ..., argk)` | Invoke the mock function's `N`-th (0-based) argument, which must be a function or a functor, with the `k` arguments. |
550 The return value of the invoked function is used as the return value of the
553 When defining a callable to be used with `Invoke*()`, you can declare any unused
554 parameters as `Unused`:
557 using ::testing::Invoke;
558 double Distance(Unused, double x, double y) { return sqrt(x*x + y*y); }
560 EXPECT_CALL(mock, Foo("Hi", _, _)).WillOnce(Invoke(Distance));
563 `Invoke(callback)` and `InvokeWithoutArgs(callback)` take ownership of
564 `callback`, which must be permanent. The type of `callback` must be a base
565 callback type instead of a derived one, e.g.
568 BlockingClosure* done = new BlockingClosure;
569 ... Invoke(done) ...; // This won't compile!
571 Closure* done2 = new BlockingClosure;
572 ... Invoke(done2) ...; // This works.
575 In `InvokeArgument<N>(...)`, if an argument needs to be passed by reference,
576 wrap it inside `ByRef()`. For example,
579 using ::testing::ByRef;
580 using ::testing::InvokeArgument;
582 InvokeArgument<2>(5, string("Hi"), ByRef(foo))
585 calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by
586 value, and `foo` by reference.
590 <!-- mdformat off(no multiline tables) -->
591 | Matcher | Description |
592 | :------------ | :----------------------------------------------------- |
593 | `DoDefault()` | Do the default action (specified by `ON_CALL()` or the built-in one). |
596 **Note:** due to technical reasons, `DoDefault()` cannot be used inside a
597 composite action - trying to do so will result in a run-time error.
599 <!-- GOOGLETEST_CM0032 DO NOT DELETE -->
601 #### Composite Actions
603 <!-- mdformat off(no multiline tables) -->
605 | :----------------------------- | :------------------------------------------ |
606 | `DoAll(a1, a2, ..., an)` | Do all actions `a1` to `an` and return the result of `an` in each invocation. The first `n - 1` sub-actions must return void. |
607 | `IgnoreResult(a)` | Perform action `a` and ignore its result. `a` must not return void. |
608 | `WithArg<N>(a)` | Pass the `N`-th (0-based) argument of the mock function to action `a` and perform it. |
609 | `WithArgs<N1, N2, ..., Nk>(a)` | Pass the selected (0-based) arguments of the mock function to action `a` and perform it. |
610 | `WithoutArgs(a)` | Perform action `a` without any arguments. |
613 #### Defining Actions
615 <table border="1" cellspacing="0" cellpadding="1">
617 <td>`struct SumAction {` <br>
618  `template <typename T>` <br>
619  `T operator()(T x, Ty) { return x + y; }` <br>
622 <td> Defines a generic functor that can be used as an action summing its
623 arguments. </td> </tr>
628 <!-- mdformat off(no multiline tables) -->
630 | :--------------------------------- | :-------------------------------------- |
631 | `ACTION(Sum) { return arg0 + arg1; }` | Defines an action `Sum()` to return the sum of the mock function's argument #0 and #1. |
632 | `ACTION_P(Plus, n) { return arg0 + n; }` | Defines an action `Plus(n)` to return the sum of the mock function's argument #0 and `n`. |
633 | `ACTION_Pk(Foo, p1, ..., pk) { statements; }` | Defines a parameterized action `Foo(p1, ..., pk)` to execute the given `statements`. |
636 The `ACTION*` macros cannot be used inside a function or class.
638 ### Cardinalities {#CardinalityList}
640 These are used in `Times()` to specify how many times a mock function will be
643 <!-- mdformat off(no multiline tables) -->
645 | :---------------- | :----------------------------------------------------- |
646 | `AnyNumber()` | The function can be called any number of times. |
647 | `AtLeast(n)` | The call is expected at least `n` times. |
648 | `AtMost(n)` | The call is expected at most `n` times. |
649 | `Between(m, n)` | The call is expected between `m` and `n` (inclusive) times. |
650 | `Exactly(n) or n` | The call is expected exactly `n` times. In particular, the call should never happen when `n` is 0. |
653 ### Expectation Order
655 By default, the expectations can be matched in *any* order. If some or all
656 expectations must be matched in a given order, there are two ways to specify it.
657 They can be used either independently or together.
659 #### The After Clause {#AfterClause}
662 using ::testing::Expectation;
664 Expectation init_x = EXPECT_CALL(foo, InitX());
665 Expectation init_y = EXPECT_CALL(foo, InitY());
666 EXPECT_CALL(foo, Bar())
667 .After(init_x, init_y);
670 says that `Bar()` can be called only after both `InitX()` and `InitY()` have
673 If you don't know how many pre-requisites an expectation has when you write it,
674 you can use an `ExpectationSet` to collect them:
677 using ::testing::ExpectationSet;
679 ExpectationSet all_inits;
680 for (int i = 0; i < element_count; i++) {
681 all_inits += EXPECT_CALL(foo, InitElement(i));
683 EXPECT_CALL(foo, Bar())
687 says that `Bar()` can be called only after all elements have been initialized
688 (but we don't care about which elements get initialized before the others).
690 Modifying an `ExpectationSet` after using it in an `.After()` doesn't affect the
691 meaning of the `.After()`.
693 #### Sequences {#UsingSequences}
695 When you have a long chain of sequential expectations, it's easier to specify
696 the order using **sequences**, which don't require you to given each expectation
697 in the chain a different name. *All expected calls* in the same sequence must
698 occur in the order they are specified.
701 using ::testing::Return;
702 using ::testing::Sequence;
705 EXPECT_CALL(foo, Reset())
707 .WillOnce(Return(true));
708 EXPECT_CALL(foo, GetSize())
710 .WillOnce(Return(1));
711 EXPECT_CALL(foo, Describe(A<const char*>()))
713 .WillOnce(Return("dummy"));
716 says that `Reset()` must be called before *both* `GetSize()` *and* `Describe()`,
717 and the latter two can occur in any order.
719 To put many expectations in a sequence conveniently:
722 using ::testing::InSequence;
733 says that all expected calls in the scope of `seq` must occur in strict order.
734 The name `seq` is irrelevant.
736 ### Verifying and Resetting a Mock
738 gMock will verify the expectations on a mock object when it is destructed, or
739 you can do it earlier:
742 using ::testing::Mock;
744 // Verifies and removes the expectations on mock_obj;
745 // returns true if and only if successful.
746 Mock::VerifyAndClearExpectations(&mock_obj);
748 // Verifies and removes the expectations on mock_obj;
749 // also removes the default actions set by ON_CALL();
750 // returns true if and only if successful.
751 Mock::VerifyAndClear(&mock_obj);
754 You can also tell gMock that a mock object can be leaked and doesn't need to be
758 Mock::AllowLeak(&mock_obj);
763 gMock defines a convenient mock class template
766 class MockFunction<R(A1, ..., An)> {
768 MOCK_METHOD(R, Call, (A1, ..., An));
772 See this [recipe](cook_book.md#using-check-points) for one application of it.
776 <!-- mdformat off(no multiline tables) -->
777 | Flag | Description |
778 | :----------------------------- | :---------------------------------------- |
779 | `--gmock_catch_leaked_mocks=0` | Don't report leaked mock objects as failures. |
780 | `--gmock_verbose=LEVEL` | Sets the default verbosity level (`info`, `warning`, or `error`) of Google Mock messages. |