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author | Abseil Team <absl-team@google.com> | 2021-05-13 20:15:34 (GMT) |
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committer | Dino Radaković <dinor@google.com> | 2021-05-18 20:48:14 (GMT) |
commit | eb6e9273dcf9c6535abb45306afe558aa961e3c3 (patch) | |
tree | cab3eeb3190d3f79e40c81dcf8d608fff5345a98 | |
parent | 662fe38e44900c007eccb65a5d2ea19df7bd520e (diff) | |
download | googletest-eb6e9273dcf9c6535abb45306afe558aa961e3c3.zip googletest-eb6e9273dcf9c6535abb45306afe558aa961e3c3.tar.gz googletest-eb6e9273dcf9c6535abb45306afe558aa961e3c3.tar.bz2 |
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Docs: Clarify that expectations must be set before mocks are exercised
PiperOrigin-RevId: 373644072
-rw-r--r-- | docs/gmock_cheat_sheet.md | 5 | ||||
-rw-r--r-- | docs/gmock_cook_book.md | 44 | ||||
-rw-r--r-- | docs/gmock_for_dummies.md | 5 |
3 files changed, 25 insertions, 29 deletions
diff --git a/docs/gmock_cheat_sheet.md b/docs/gmock_cheat_sheet.md index c1d1a50..2545c61 100644 --- a/docs/gmock_cheat_sheet.md +++ b/docs/gmock_cheat_sheet.md @@ -344,6 +344,11 @@ Mock::VerifyAndClearExpectations(&mock_obj); Mock::VerifyAndClear(&mock_obj); ``` +Do not set new expectations after verifying and clearing a mock after its use. +Setting expectations after code that exercises the mock has undefined behavior. +See [Using Mocks in Tests](gmock_for_dummies.md#using-mocks-in-tests) for more +information. + You can also tell gMock that a mock object can be leaked and doesn't need to be verified: diff --git a/docs/gmock_cook_book.md b/docs/gmock_cook_book.md index 891c35c..1d07d01 100644 --- a/docs/gmock_cook_book.md +++ b/docs/gmock_cook_book.md @@ -3017,31 +3017,21 @@ indicate whether the verification was successful (`true` for yes), so you can wrap that function call inside a `ASSERT_TRUE()` if there is no point going further when the verification has failed. -### Using Check Points {#UsingCheckPoints} +Do not set new expectations after verifying and clearing a mock after its use. +Setting expectations after code that exercises the mock has undefined behavior. +See [Using Mocks in Tests](gmock_for_dummies.md#using-mocks-in-tests) for more +information. -Sometimes you may want to "reset" a mock object at various check points in your -test: at each check point, you verify that all existing expectations on the mock -object have been satisfied, and then you set some new expectations on it as if -it's newly created. This allows you to work with a mock object in "phases" whose -sizes are each manageable. +### Using Checkpoints {#UsingCheckPoints} -One such scenario is that in your test's `SetUp()` function, you may want to put -the object you are testing into a certain state, with the help from a mock -object. Once in the desired state, you want to clear all expectations on the -mock, such that in the `TEST_F` body you can set fresh expectations on it. +Sometimes you might want to test a mock object's behavior in phases whose sizes +are each manageable, or you might want to set more detailed expectations about +which API calls invoke which mock functions. -As you may have figured out, the `Mock::VerifyAndClearExpectations()` function -we saw in the previous recipe can help you here. Or, if you are using -`ON_CALL()` to set default actions on the mock object and want to clear the -default actions as well, use `Mock::VerifyAndClear(&mock_object)` instead. This -function does what `Mock::VerifyAndClearExpectations(&mock_object)` does and -returns the same `bool`, **plus** it clears the `ON_CALL()` statements on -`mock_object` too. - -Another trick you can use to achieve the same effect is to put the expectations -in sequences and insert calls to a dummy "check-point" function at specific -places. Then you can verify that the mock function calls do happen at the right -time. For example, if you are exercising code: +A technique you can use is to put the expectations in a sequence and insert +calls to a dummy "checkpoint" function at specific places. Then you can verify +that the mock function calls do happen at the right time. For example, if you +are exercising the code: ```cpp Foo(1); @@ -3050,7 +3040,7 @@ time. For example, if you are exercising code: ``` and want to verify that `Foo(1)` and `Foo(3)` both invoke `mock.Bar("a")`, but -`Foo(2)` doesn't invoke anything. You can write: +`Foo(2)` doesn't invoke anything, you can write: ```cpp using ::testing::MockFunction; @@ -3076,10 +3066,10 @@ TEST(FooTest, InvokesBarCorrectly) { } ``` -The expectation spec says that the first `Bar("a")` must happen before check -point "1", the second `Bar("a")` must happen after check point "2", and nothing -should happen between the two check points. The explicit check points make it -easy to tell which `Bar("a")` is called by which call to `Foo()`. +The expectation spec says that the first `Bar("a")` call must happen before +checkpoint "1", the second `Bar("a")` call must happen after checkpoint "2", and +nothing should happen between the two checkpoints. The explicit checkpoints make +it clear which `Bar("a")` is called by which call to `Foo()`. ### Mocking Destructors diff --git a/docs/gmock_for_dummies.md b/docs/gmock_for_dummies.md index 370f17e..1f4cc24 100644 --- a/docs/gmock_for_dummies.md +++ b/docs/gmock_for_dummies.md @@ -262,8 +262,9 @@ when you allocate mocks on the heap. You get that automatically if you use the `gtest_main` library already. **Important note:** gMock requires expectations to be set **before** the mock -functions are called, otherwise the behavior is **undefined**. In particular, -you mustn't interleave `EXPECT_CALL()s` and calls to the mock functions. +functions are called, otherwise the behavior is **undefined**. Do not alternate +between calls to `EXPECT_CALL()` and calls to the mock functions, and do not set +any expectations on a mock after passing the mock to an API. This means `EXPECT_CALL()` should be read as expecting that a call will occur *in the future*, not that a call has occurred. Why does gMock work like that? |