diff options
author | Abseil Team <absl-team@google.com> | 2021-04-27 20:22:33 (GMT) |
---|---|---|
committer | Derek Mauro <dmauro@google.com> | 2021-04-29 14:40:29 (GMT) |
commit | 680a5aa337d655b916e9048fe8f2ff69e9d4998a (patch) | |
tree | 263a2fa805ac7a6ce77da4a0245d0cba60e02548 /docs/gmock_cheat_sheet.md | |
parent | 719fd2d36fdf98d14ae15618c96d445e7fe00843 (diff) | |
download | googletest-680a5aa337d655b916e9048fe8f2ff69e9d4998a.zip googletest-680a5aa337d655b916e9048fe8f2ff69e9d4998a.tar.gz googletest-680a5aa337d655b916e9048fe8f2ff69e9d4998a.tar.bz2 |
Googletest export
Move matchers reference from cheat sheet into its own document
PiperOrigin-RevId: 370749693
Diffstat (limited to 'docs/gmock_cheat_sheet.md')
-rw-r--r-- | docs/gmock_cheat_sheet.md | 281 |
1 files changed, 1 insertions, 280 deletions
diff --git a/docs/gmock_cheat_sheet.md b/docs/gmock_cheat_sheet.md index 8e371fc..cda9ddd 100644 --- a/docs/gmock_cheat_sheet.md +++ b/docs/gmock_cheat_sheet.md @@ -224,286 +224,7 @@ and the default action will be taken each time. ## Matchers {#MatcherList} -A **matcher** matches a *single* argument. You can use it inside `ON_CALL()` or -`EXPECT_CALL()`, or use it to validate a value directly using two macros: - -| Macro | Description | -| :----------------------------------- | :------------------------------------ | -| `EXPECT_THAT(actual_value, matcher)` | Asserts that `actual_value` matches `matcher`. | -| `ASSERT_THAT(actual_value, matcher)` | The same as `EXPECT_THAT(actual_value, matcher)`, except that it generates a **fatal** failure. | - -{: .callout .note} -**Note:** Although equality matching via `EXPECT_THAT(actual_value, -expected_value)` is supported, prefer to make the comparison explicit via -`EXPECT_THAT(actual_value, Eq(expected_value))` or `EXPECT_EQ(actual_value, -expected_value)`. - -Built-in matchers (where `argument` is the function argument, e.g. -`actual_value` in the example above, or when used in the context of -`EXPECT_CALL(mock_object, method(matchers))`, the arguments of `method`) 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` | -| `IsFalse()` | `argument` evaluates to `false` in a Boolean context. | -| `IsTrue()` | `argument` evaluates to `true` in a Boolean context. | -| `IsNull()` | `argument` is a `NULL` pointer (raw or smart). | -| `NotNull()` | `argument` is a non-null pointer (raw or smart). | -| `Optional(m)` | `argument` is `optional<>` that contains a value matching `m`. (For testing whether an `optional<>` is set, check for equality with `nullopt`. You may need to use `Eq(nullopt)` if the inner type doesn't have `==`.)| -| `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 `std::ref()`, e.g. -`Eq(std::ref(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. - -`IsTrue` and `IsFalse` are useful when you need to use a matcher, or for types -that can be explicitly converted to Boolean, but are not implicitly converted to -Boolean. In other cases, you can use the basic -[`EXPECT_TRUE` and `EXPECT_FALSE`](primer.md#basic-assertions) assertions. - -### Floating-Point Matchers {#FpMatchers} - -| 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. | -| `IsNan()` | `argument` is any floating-point type with a NaN value. | - -The above matchers use ULP-based comparison (the same as used in 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. | -| `IsEmpty()` | `argument` is an empty 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()` take ownership of the `RE` object. They -use the regular expression syntax defined -[here](advanced.md#regular-expression-syntax). All of these matchers, except -`ContainsRegex()` and `MatchesRegex()` 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 | -| :---------------------------------------- | :------------------------------- | -| `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. | -| `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. | -| `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. | -| `IsEmpty()` | `argument` is an empty container (`container.empty()`). | -| `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. | -| `IsSupersetOf({e0, e1, ..., en})`, `IsSupersetOf(a_container)`, `IsSupersetOf(begin, end)`, `IsSupersetOf(array)`, or `IsSupersetOf(array, count)` | Some subset of `argument` matches `UnorderedElementsAre(`expected matchers`)`. | -| `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. | -| `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 of the elements, each element matches an `ei` (for a different `i`), which can be a value or a matcher. | -| `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. | -| `UnorderedPointwise(m, container)`, `UnorderedPointwise(m, {e0, e1, ..., en})` | Like `Pointwise(m, container)`, but ignores the order of elements. | -| `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(), 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 - 2. an array passed as a pointer and a count (e.g. in `Bar(const T* buffer, - int len)` -- see [Multi-argument Matchers](#MultiArgMatchers)). -* The array being matched may be multi-dimensional (i.e. its elements can be - arrays). -* `m` in `Pointwise(m, ...)` and `UnorderedPointwise(m, ...)` should be a - matcher for `::std::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==`, - one might write: - - ```cpp - using ::std::get; - MATCHER(FooEq, "") { - return std::get<0>(arg).Equals(std::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_. | -| `Field(field_name, &class::field, m)` | The same as the two-parameter version, but provides a better error message. | -| `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`. | -| `FieldsAre(m...)` | `argument` is a compatible object where each field matches piecewise with the matchers `m...`. A compatible object is any that supports the `std::tuple_size<Obj>`+`get<I>(obj)` protocol. In C++17 and up this also supports types compatible with structured bindings, like aggregates. | -| `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_. The method `property()` must take no argument and be declared as `const`. | -| `Property(property_name, &class::property, m)` | The same as the two-parameter version, but provides a better error message. - -**Notes:** - -* You can use `FieldsAre()` to match any type that supports structured - bindings, such as `std::tuple`, `std::pair`, `std::array`, and aggregate - types. For example: - - ```cpp - std::tuple<int, std::string> my_tuple{7, "hello world"}; - EXPECT_THAT(my_tuple, FieldsAre(Ge(0), HasSubstr("hello"))); - - struct MyStruct { - int value = 42; - std::string greeting = "aloha"; - }; - MyStruct s; - EXPECT_THAT(s, FieldsAre(42, "aloha")); - ``` - -* Don't use `Property()` against member functions that you do not own, because - taking addresses of functions is fragile and generally not part of the - contract of the function. - -### Matching the Result of a Function, Functor, or Callback - -| Matcher | Description | -| :--------------- | :------------------------------------------------ | -| `ResultOf(f, m)` | `f(argument)` matches matcher `m`, where `f` is a function or functor. | - -### Pointer Matchers - -| Matcher | Description | -| :------------------------ | :---------------------------------------------- | -| `Address(m)` | the result of `std::addressof(argument)` matches `m`. | -| `Pointee(m)` | `argument` (either a smart pointer or a raw pointer) points to a value that matches matcher `m`. | -| `Pointer(m)` | `argument` (either a smart pointer or a raw pointer) contains a pointer that matches `m`. `m` will match against the raw pointer regardless of the type of `argument`. | -| `WhenDynamicCastTo<T>(m)` | when `argument` is passed through `dynamic_cast<T>()`, it matches matcher `m`. | - -### Multi-argument Matchers {#MultiArgMatchers} - -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`. | -| `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. | -| `AnyOf(m1, m2, ..., mn)` | `argument` matches at least one of the matchers `m1` to `mn`. | -| `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. | -| `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](gmock_cook_book.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. | - -`AddressSatisfies(callback)` and `Truly(callback)` take ownership of `callback`, -which must be a permanent callback. - -### Using Matchers as Predicates {#MatchersAsPredicatesCheat} - -| 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 matcher `IsDivisibleBy(n)` to match a number divisible by `n`. | -| `MATCHER_P2(IsBetween, a, b, absl::StrCat(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. -2. 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). -3. You can use `PrintToString(x)` to convert a value `x` of any type to a - string. -4. You can use `ExplainMatchResult()` in a custom matcher to wrap another - matcher, for example: - - ```cpp - MATCHER_P(NestedPropertyMatches, matcher, "") { - return ExplainMatchResult(matcher, arg.nested().property(), result_listener); - } - ``` +See the [Matchers Reference](reference/matchers.md). ## Actions {#ActionList} |