1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
|
# Defining a Mock Class #
## Mocking a Normal Class ##
Given
```cpp
class Foo {
...
virtual ~Foo();
virtual int GetSize() const = 0;
virtual string Describe(const char* name) = 0;
virtual string Describe(int type) = 0;
virtual bool Process(Bar elem, int count) = 0;
};
```
(note that `~Foo()` **must** be virtual) we can define its mock as
```cpp
#include "gmock/gmock.h"
class MockFoo : public Foo {
MOCK_CONST_METHOD0(GetSize, int());
MOCK_METHOD1(Describe, string(const char* name));
MOCK_METHOD1(Describe, string(int type));
MOCK_METHOD2(Process, bool(Bar elem, int count));
};
```
To create a "nice" mock object which ignores all uninteresting calls,
or a "strict" mock object, which treats them as failures:
```cpp
NiceMock<MockFoo> nice_foo; // The type is a subclass of MockFoo.
StrictMock<MockFoo> strict_foo; // The type is a subclass of MockFoo.
```
## Mocking a Class Template ##
To mock
```cpp
template <typename Elem>
class StackInterface {
public:
...
virtual ~StackInterface();
virtual int GetSize() const = 0;
virtual void Push(const Elem& x) = 0;
};
```
(note that `~StackInterface()` **must** be virtual) just append `_T` to the `MOCK_*` macros:
```cpp
template <typename Elem>
class MockStack : public StackInterface<Elem> {
public:
...
MOCK_CONST_METHOD0_T(GetSize, int());
MOCK_METHOD1_T(Push, void(const Elem& x));
};
```
## Specifying Calling Conventions for Mock Functions ##
If your mock function doesn't use the default calling convention, you
can specify it by appending `_WITH_CALLTYPE` to any of the macros
described in the previous two sections and supplying the calling
convention as the first argument to the macro. For example,
```cpp
MOCK_METHOD1_WITH_CALLTYPE(STDMETHODCALLTYPE, Foo, bool(int n));
MOCK_CONST_METHOD2_WITH_CALLTYPE(STDMETHODCALLTYPE, Bar, int(double x, double y));
```
where `STDMETHODCALLTYPE` is defined by `<objbase.h>` on Windows.
# Using Mocks in Tests #
The typical flow is:
1. Import the Google Mock names you need to use. All Google Mock names are in the `testing` namespace unless they are macros or otherwise noted.
1. Create the mock objects.
1. Optionally, set the default actions of the mock objects.
1. Set your expectations on the mock objects (How will they be called? What wil they do?).
1. Exercise code that uses the mock objects; if necessary, check the result using [Google Test](../../googletest/) assertions.
1. When a mock objects is destructed, Google Mock automatically verifies that all expectations on it have been satisfied.
Here is an example:
```cpp
using ::testing::Return; // #1
TEST(BarTest, DoesThis) {
MockFoo foo; // #2
ON_CALL(foo, GetSize()) // #3
.WillByDefault(Return(1));
// ... other default actions ...
EXPECT_CALL(foo, Describe(5)) // #4
.Times(3)
.WillRepeatedly(Return("Category 5"));
// ... other expectations ...
EXPECT_EQ("good", MyProductionFunction(&foo)); // #5
} // #6
```
# Setting Default Actions #
Google Mock has a **built-in default action** for any function that
returns `void`, `bool`, a numeric value, or a pointer.
To customize the default action for functions with return type `T` globally:
```cpp
using ::testing::DefaultValue;
// Sets the default value to be returned. T must be CopyConstructible.
DefaultValue<T>::Set(value);
// Sets a factory. Will be invoked on demand. T must be MoveConstructible.
// T MakeT();
DefaultValue<T>::SetFactory(&MakeT);
// ... use the mocks ...
// Resets the default value.
DefaultValue<T>::Clear();
```
To customize the default action for a particular method, use `ON_CALL()`:
```cpp
ON_CALL(mock_object, method(matchers))
.With(multi_argument_matcher) ?
.WillByDefault(action);
```
# Setting Expectations #
`EXPECT_CALL()` sets **expectations** on a mock method (How will it be
called? What will it do?):
```cpp
EXPECT_CALL(mock_object, method(matchers))
.With(multi_argument_matcher) ?
.Times(cardinality) ?
.InSequence(sequences) *
.After(expectations) *
.WillOnce(action) *
.WillRepeatedly(action) ?
.RetiresOnSaturation(); ?
```
If `Times()` is omitted, the cardinality is assumed to be:
* `Times(1)` when there is neither `WillOnce()` nor `WillRepeatedly()`;
* `Times(n)` when there are `n WillOnce()`s but no `WillRepeatedly()`, where `n` >= 1; or
* `Times(AtLeast(n))` when there are `n WillOnce()`s and a `WillRepeatedly()`, where `n` >= 0.
A method with no `EXPECT_CALL()` is free to be invoked _any number of times_, and the default action will be taken each time.
# Matchers #
A **matcher** matches a _single_ argument. You can use it inside
`ON_CALL()` or `EXPECT_CALL()`, or use it to validate a value
directly:
| Matcher | Description |
|:--------|:------------|
| `EXPECT_THAT(value, matcher)` | Asserts that `value` matches `matcher`. |
| `ASSERT_THAT(value, matcher)` | The same as `EXPECT_THAT(value, matcher)`, except that it generates a **fatal** failure. |
Built-in matchers (where `argument` is the function argument) are
divided into several categories:
## Wildcard ##
| Matcher | Description |
|:--------|:------------|
|`_`|`argument` can be any value of the correct type.|
|`A<type>()` or `An<type>()`|`argument` can be any value of type `type`. |
## Generic Comparison ##
| Matcher | Description |
|:---------------------|:------------------|
|`Eq(value)` or `value`|`argument == value`|
|`Ge(value)` |`argument >= value`|
|`Gt(value)` |`argument > value` |
|`Le(value)` |`argument <= value`|
|`Lt(value)` |`argument < value` |
|`Ne(value)` |`argument != value`|
|`IsNull()` |`argument` is a `NULL` pointer (raw or smart).|
|`NotNull()` |`argument` is a non-null pointer (raw or smart).|
|`VariantWith<T>(m)` |`argument` is `variant<>` that holds the alternative of type T with a value matching `m`.|
|`Ref(variable)` |`argument` is a reference to `variable`.|
|`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.|
Except `Ref()`, these matchers make a _copy_ of `value` in case it's
modified or destructed later. If the compiler complains that `value`
doesn't have a public copy constructor, try wrap it in `ByRef()`,
e.g. `Eq(ByRef(non_copyable_value))`. If you do that, make sure
`non_copyable_value` is not changed afterwards, or the meaning of your
matcher will be changed.
## Floating-Point Matchers ##
| Matcher | Description |
|:-------------------|:---------------------------------------------------------------------------------------------------------|
|`DoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as unequal. |
|`FloatEq(a_float)` |`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as unequal. |
|`NanSensitiveDoubleEq(a_double)`|`argument` is a `double` value approximately equal to `a_double`, treating two NaNs as equal. |
|`NanSensitiveFloatEq(a_float)`|`argument` is a `float` value approximately equal to `a_float`, treating two NaNs as equal. |
The above matchers use ULP-based comparison (the same as used in
[Google Test](../../googletest/)). They
automatically pick a reasonable error bound based on the absolute
value of the expected value. `DoubleEq()` and `FloatEq()` conform to
the IEEE standard, which requires comparing two NaNs for equality to
return false. The `NanSensitive*` version instead treats two NaNs as
equal, which is often what a user wants.
| Matcher | Description |
|:--------|:------------|
|`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.|
|`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.|
|`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.|
|`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.|
## String Matchers ##
The `argument` can be either a C string or a C++ string object:
| Matcher | Description |
|:----------------------|:--------------------------------------------------|
|`ContainsRegex(string)`|`argument` matches the given regular expression. |
|`EndsWith(suffix)` |`argument` ends with string `suffix`. |
|`HasSubstr(string)` |`argument` contains `string` as a sub-string. |
|`MatchesRegex(string)` |`argument` matches the given regular expression with the match starting at the first character and ending at the last character.|
|`StartsWith(prefix)` |`argument` starts with string `prefix`. |
|`StrCaseEq(string)` |`argument` is equal to `string`, ignoring case. |
|`StrCaseNe(string)` |`argument` is not equal to `string`, ignoring case.|
|`StrEq(string)` |`argument` is equal to `string`. |
|`StrNe(string)` |`argument` is not equal to `string`. |
`ContainsRegex()` and `MatchesRegex()` use the regular expression
syntax defined
[here](../../googletest/docs/advanced.md#regular-expression-syntax).
`StrCaseEq()`, `StrCaseNe()`, `StrEq()`, and `StrNe()` work for wide
strings as well.
## Container Matchers ##
Most STL-style containers support `==`, so you can use
`Eq(expected_container)` or simply `expected_container` to match a
container exactly. If you want to write the elements in-line,
match them more flexibly, or get more informative messages, you can use:
| Matcher | Description |
|:--------|:------------|
| `ContainerEq(container)` | The same as `Eq(container)` except that the failure message also includes which elements are in one container but not the other. |
| `Contains(e)` | `argument` contains an element that matches `e`, which can be either a value or a matcher. |
| `Each(e)` | `argument` is a container where _every_ element matches `e`, which can be either a value or a matcher. |
| `ElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, where the i-th element matches `ei`, which can be a value or a matcher. 0 to 10 arguments are allowed. |
| `ElementsAreArray({ e0, e1, ..., en })`, `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, or C-style array. |
| `IsEmpty()` | `argument` is an empty container (`container.empty()`). |
| `Pointwise(m, container)` | `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. |
| `SizeIs(m)` | `argument` is a container whose size matches `m`. E.g. `SizeIs(2)` or `SizeIs(Lt(2))`. |
| `UnorderedElementsAre(e0, e1, ..., en)` | `argument` has `n + 1` elements, and under some permutation each element matches an `ei` (for a different `i`), which can be a value or a matcher. 0 to 10 arguments are allowed. |
| `UnorderedElementsAreArray({ e0, e1, ..., en })`, `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, or C-style array. |
| `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. |
| `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<int>(), ElementsAre(3, 2, 1))`. |
Notes:
* These matchers can also match:
1. a native array passed by reference (e.g. in `Foo(const int (&a)[5])`), and
1. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer, int len)` -- see [Multi-argument Matchers](#Multiargument_Matchers.md)).
* The array being matched may be multi-dimensional (i.e. its elements can be arrays).
* `m` in `Pointwise(m, ...)` should be a matcher for `::testing::tuple<T, U>` where `T` and `U` are the element type of the actual container and the expected container, respectively. For example, to compare two `Foo` containers where `Foo` doesn't support `operator==` but has an `Equals()` method, one might write:
```cpp
using ::testing::get;
MATCHER(FooEq, "") {
return get<0>(arg).Equals(get<1>(arg));
}
...
EXPECT_THAT(actual_foos, Pointwise(FooEq(), expected_foos));
```
## Member Matchers ##
| Matcher | Description |
|:--------|:------------|
|`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_.|
|`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`.|
|`Pair(m1, m2)`|`argument` is an `std::pair` whose `first` field matches `m1` and `second` field matches `m2`.|
|`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_.|
## Matching the Result of a Function or Functor ##
| Matcher | Description |
|:---------------|:---------------------------------------------------------------------|
|`ResultOf(f, m)`|`f(argument)` matches matcher `m`, where `f` is a function or functor.|
## Pointer Matchers ##
| Matcher | Description |
|:------------------------|:-----------------------------------------------------------------------------------------------|
|`Pointee(m)` |`argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`.|
|`WhenDynamicCastTo<T>(m)`| when `argument` is passed through `dynamic_cast<T>()`, it matches matcher `m`. |
## Multiargument Matchers ##
Technically, all matchers match a _single_ value. A "multi-argument"
matcher is just one that matches a _tuple_. The following matchers can
be used to match a tuple `(x, y)`:
| Matcher | Description |
|:--------|:------------|
|`Eq()`|`x == y`|
|`Ge()`|`x >= y`|
|`Gt()`|`x > y` |
|`Le()`|`x <= y`|
|`Lt()`|`x < y` |
|`Ne()`|`x != y`|
You can use the following selectors to pick a subset of the arguments
(or reorder them) to participate in the matching:
| Matcher | Description |
|:--------|:------------|
|`AllArgs(m)`|Equivalent to `m`. Useful as syntactic sugar in `.With(AllArgs(m))`.|
|`Args<N1, N2, ..., Nk>(m)`|The tuple of the `k` selected (using 0-based indices) arguments matches `m`, e.g. `Args<1, 2>(Eq())`.|
## Composite Matchers ##
You can make a matcher from one or more other matchers:
| Matcher | Description |
|:-----------------------|:------------------------------------------------------------|
|`AllOf(m1, m2, ..., mn)`|`argument` matches all of the matchers `m1` to `mn`. |
|`AnyOf(m1, m2, ..., mn)`|`argument` matches at least one of the matchers `m1` to `mn`.|
|`Not(m)` |`argument` doesn't match matcher `m`. |
## Adapters for Matchers ##
| Matcher | Description |
|:--------|:------------|
|`MatcherCast<T>(m)`|casts matcher `m` to type `Matcher<T>`.|
|`SafeMatcherCast<T>(m)`| [safely casts](CookBook.md#casting-matchers) matcher `m` to type `Matcher<T>`.|
|`Truly(predicate)`|`predicate(argument)` returns something considered by C++ to be true, where `predicate` is a function or functor.|
## Matchers as Predicates ##
| Matcher | Description |
|:--------|:------------|
|`Matches(m)(value)`|evaluates to `true` if `value` matches `m`. You can use `Matches(m)` alone as a unary functor.|
|`ExplainMatchResult(m, value, result_listener)`|evaluates to `true` if `value` matches `m`, explaining the result to `result_listener`.|
|`Value(value, m)`|evaluates to `true` if `value` matches `m`.|
## Defining Matchers ##
| Matcher | Description |
|:--------|:------------|
| `MATCHER(IsEven, "") { return (arg % 2) == 0; }` | Defines a matcher `IsEven()` to match an even number. |
| `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`. |
| `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`]. |
**Notes:**
1. The `MATCHER*` macros cannot be used inside a function or class.
1. The matcher body must be _purely functional_ (i.e. it cannot have any side effect, and the result must not depend on anything other than the value being matched and the matcher parameters).
1. You can use `PrintToString(x)` to convert a value `x` of any type to a string.
## Matchers as Test Assertions ##
| Matcher | Description |
|:--------|:------------|
|`ASSERT_THAT(expression, m)`|Generates a [fatal failure](../../googletest/docs/primer.md#assertions) if the value of `expression` doesn't match matcher `m`.|
|`EXPECT_THAT(expression, m)`|Generates a non-fatal failure if the value of `expression` doesn't match matcher `m`.|
# Actions #
**Actions** specify what a mock function should do when invoked.
## Returning a Value ##
| Matcher | Description |
|:--------|:------------|
|`Return()`|Return from a `void` mock function.|
|`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.|
|`ReturnArg<N>()`|Return the `N`-th (0-based) argument.|
|`ReturnNew<T>(a1, ..., ak)`|Return `new T(a1, ..., ak)`; a different object is created each time.|
|`ReturnNull()`|Return a null pointer.|
|`ReturnPointee(ptr)`|Return the value pointed to by `ptr`.|
|`ReturnRef(variable)`|Return a reference to `variable`.|
|`ReturnRefOfCopy(value)`|Return a reference to a copy of `value`; the copy lives as long as the action.|
## Side Effects ##
| Matcher | Description |
|:--------|:------------|
|`Assign(&variable, value)`|Assign `value` to variable.|
|`DeleteArg<N>()`| Delete the `N`-th (0-based) argument, which must be a pointer.|
|`SaveArg<N>(pointer)`| Save the `N`-th (0-based) argument to `*pointer`.|
|`SaveArgPointee<N>(pointer)`| Save the value pointed to by the `N`-th (0-based) argument to `*pointer`.|
|`SetArgReferee<N>(value)` | Assign value to the variable referenced by the `N`-th (0-based) argument. |
|`SetArgPointee<N>(value)` |Assign `value` to the variable pointed by the `N`-th (0-based) argument.|
|`SetArgumentPointee<N>(value)`|Same as `SetArgPointee<N>(value)`. Deprecated. Will be removed in v1.7.0.|
|`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.|
|`SetErrnoAndReturn(error, value)`|Set `errno` to `error` and return `value`.|
|`Throw(exception)`|Throws the given exception, which can be any copyable value. Available since v1.1.0.|
## Using a Function or a Functor as an Action ##
| Matcher | Description |
|:--------|:------------|
|`Invoke(f)`|Invoke `f` with the arguments passed to the mock function, where `f` can be a global/static function or a functor.|
|`Invoke(object_pointer, &class::method)`|Invoke the {method on the object with the arguments passed to the mock function.|
|`InvokeWithoutArgs(f)`|Invoke `f`, which can be a global/static function or a functor. `f` must take no arguments.|
|`InvokeWithoutArgs(object_pointer, &class::method)`|Invoke the method on the object, which takes no arguments.|
|`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.|
The return value of the invoked function is used as the return value
of the action.
When defining a function or functor to be used with `Invoke*()`, you can declare any unused parameters as `Unused`:
```cpp
double Distance(Unused, double x, double y) { return sqrt(x*x + y*y); }
...
EXPECT_CALL(mock, Foo("Hi", _, _)).WillOnce(Invoke(Distance));
```
In `InvokeArgument<N>(...)`, if an argument needs to be passed by reference, wrap it inside `ByRef()`. For example,
```cpp
InvokeArgument<2>(5, string("Hi"), ByRef(foo))
```
calls the mock function's #2 argument, passing to it `5` and `string("Hi")` by value, and `foo` by reference.
## Default Action ##
| Matcher | Description |
|:--------|:------------|
|`DoDefault()`|Do the default action (specified by `ON_CALL()` or the built-in one).|
**Note:** due to technical reasons, `DoDefault()` cannot be used inside a composite action - trying to do so will result in a run-time error.
## Composite Actions ##
| Matcher | Description |
|:-----------------------------|:-----------------------------------------------------------------------------------------------------------------------------|
|`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. |
|`IgnoreResult(a)` |Perform action `a` and ignore its result. `a` must not return void. |
|`WithArg<N>(a)` |Pass the `N`-th (0-based) argument of the mock function to action `a` and perform it. |
|`WithArgs<N1, N2, ..., Nk>(a)`|Pass the selected (0-based) arguments of the mock function to action `a` and perform it. |
|`WithoutArgs(a)` |Perform action `a` without any arguments. |
## Defining Actions ##
| Matcher | Description |
|:----------------------------------------------|:------------------------------------------------------------------------------------------|
| `ACTION(Sum) { return arg0 + arg1; }` | Defines an action `Sum()` to return the sum of the mock function's argument #0 and #1. |
| `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`. |
| `ACTION_Pk(Foo, p1, ..., pk) { statements; }` | Defines a parameterized action `Foo(p1, ..., pk)` to execute the given `statements`. |
The `ACTION*` macros cannot be used inside a function or class.
# Cardinalities #
These are used in `Times()` to specify how many times a mock function will be called:
| Matcher | Description |
|:--------|:------------|
|`AnyNumber()`|The function can be called any number of times.|
|`AtLeast(n)`|The call is expected at least `n` times.|
|`AtMost(n)`|The call is expected at most `n` times.|
|`Between(m, n)`|The call is expected between `m` and `n` (inclusive) times.|
|`Exactly(n) or n`|The call is expected exactly `n` times. In particular, the call should never happen when `n` is 0.|
# Expectation Order #
By default, the expectations can be matched in _any_ order. If some
or all expectations must be matched in a given order, there are two
ways to specify it. They can be used either independently or
together.
## The After Clause ##
```cpp
using ::testing::Expectation;
...
Expectation init_x = EXPECT_CALL(foo, InitX());
Expectation init_y = EXPECT_CALL(foo, InitY());
EXPECT_CALL(foo, Bar())
.After(init_x, init_y);
```
says that `Bar()` can be called only after both `InitX()` and
`InitY()` have been called.
If you don't know how many pre-requisites an expectation has when you
write it, you can use an `ExpectationSet` to collect them:
```cpp
using ::testing::ExpectationSet;
...
ExpectationSet all_inits;
for (int i = 0; i < element_count; i++) {
all_inits += EXPECT_CALL(foo, InitElement(i));
}
EXPECT_CALL(foo, Bar())
.After(all_inits);
```
says that `Bar()` can be called only after all elements have been
initialized (but we don't care about which elements get initialized
before the others).
Modifying an `ExpectationSet` after using it in an `.After()` doesn't
affect the meaning of the `.After()`.
## Sequences ##
When you have a long chain of sequential expectations, it's easier to
specify the order using **sequences**, which don't require you to given
each expectation in the chain a different name. <i>All expected<br>
calls</i> in the same sequence must occur in the order they are
specified.
```cpp
using ::testing::Sequence;
Sequence s1, s2;
...
EXPECT_CALL(foo, Reset())
.InSequence(s1, s2)
.WillOnce(Return(true));
EXPECT_CALL(foo, GetSize())
.InSequence(s1)
.WillOnce(Return(1));
EXPECT_CALL(foo, Describe(A<const char*>()))
.InSequence(s2)
.WillOnce(Return("dummy"));
```
says that `Reset()` must be called before _both_ `GetSize()` _and_
`Describe()`, and the latter two can occur in any order.
To put many expectations in a sequence conveniently:
```cpp
using ::testing::InSequence;
{
InSequence dummy;
EXPECT_CALL(...)...;
EXPECT_CALL(...)...;
...
EXPECT_CALL(...)...;
}
```
says that all expected calls in the scope of `dummy` must occur in
strict order. The name `dummy` is irrelevant.)
# Verifying and Resetting a Mock #
Google Mock will verify the expectations on a mock object when it is destructed, or you can do it earlier:
```cpp
using ::testing::Mock;
...
// Verifies and removes the expectations on mock_obj;
// returns true iff successful.
Mock::VerifyAndClearExpectations(&mock_obj);
...
// Verifies and removes the expectations on mock_obj;
// also removes the default actions set by ON_CALL();
// returns true iff successful.
Mock::VerifyAndClear(&mock_obj);
```
You can also tell Google Mock that a mock object can be leaked and doesn't
need to be verified:
```cpp
Mock::AllowLeak(&mock_obj);
```
# Mock Classes #
Google Mock defines a convenient mock class template
```cpp
class MockFunction<R(A1, ..., An)> {
public:
MOCK_METHODn(Call, R(A1, ..., An));
};
```
See this [recipe](CookBook.md#using-check-points) for one application of it.
# Flags #
| Flag | Description |
|:--------|:------------|
| `--gmock_catch_leaked_mocks=0` | Don't report leaked mock objects as failures. |
| `--gmock_verbose=LEVEL` | Sets the default verbosity level (`info`, `warning`, or `error`) of Google Mock messages. |
|