diff options
Diffstat (limited to 'docs/reference/assertions.md')
| -rw-r--r-- | docs/reference/assertions.md | 633 |
1 files changed, 633 insertions, 0 deletions
diff --git a/docs/reference/assertions.md b/docs/reference/assertions.md new file mode 100644 index 00000000..492ff5ef --- /dev/null +++ b/docs/reference/assertions.md @@ -0,0 +1,633 @@ +# Assertions Reference + +This page lists the assertion macros provided by GoogleTest for verifying code +behavior. To use them, add `#include <gtest/gtest.h>`. + +The majority of the macros listed below come as a pair with an `EXPECT_` variant +and an `ASSERT_` variant. Upon failure, `EXPECT_` macros generate nonfatal +failures and allow the current function to continue running, while `ASSERT_` +macros generate fatal failures and abort the current function. + +All assertion macros support streaming a custom failure message into them with +the `<<` operator, for example: + +```cpp +EXPECT_TRUE(my_condition) << "My condition is not true"; +``` + +Anything that can be streamed to an `ostream` can be streamed to an assertion +macro—in particular, C strings and string objects. If a wide string (`wchar_t*`, +`TCHAR*` in `UNICODE` mode on Windows, or `std::wstring`) is streamed to an +assertion, it will be translated to UTF-8 when printed. + +## Explicit Success and Failure {#success-failure} + +The assertions in this section generate a success or failure directly instead of +testing a value or expression. These are useful when control flow, rather than a +Boolean expression, determines the test's success or failure, as shown by the +following example: + +```c++ +switch(expression) { + case 1: + ... some checks ... + case 2: + ... some other checks ... + default: + FAIL() << "We shouldn't get here."; +} +``` + +### SUCCEED {#SUCCEED} + +`SUCCEED()` + +Generates a success. This *does not* make the overall test succeed. A test is +considered successful only if none of its assertions fail during its execution. + +The `SUCCEED` assertion is purely documentary and currently doesn't generate any +user-visible output. However, we may add `SUCCEED` messages to GoogleTest output +in the future. + +### FAIL {#FAIL} + +`FAIL()` + +Generates a fatal failure, which returns from the current function. + +Can only be used in functions that return `void`. See +[Assertion Placement](../advanced.md#assertion-placement) for more information. + +### ADD_FAILURE {#ADD_FAILURE} + +`ADD_FAILURE()` + +Generates a nonfatal failure, which allows the current function to continue +running. + +### ADD_FAILURE_AT {#ADD_FAILURE_AT} + +`ADD_FAILURE_AT(`*`file_path`*`,`*`line_number`*`)` + +Generates a nonfatal failure at the file and line number specified. + +## Generalized Assertion {#generalized} + +The following assertion allows [matchers](matchers.md) to be used to verify +values. + +### EXPECT_THAT {#EXPECT_THAT} + +`EXPECT_THAT(`*`value`*`,`*`matcher`*`)` \ +`ASSERT_THAT(`*`value`*`,`*`matcher`*`)` + +Verifies that *`value`* matches the [matcher](matchers.md) *`matcher`*. + +For example, the following code verifies that the string `value1` starts with +`"Hello"`, `value2` matches a regular expression, and `value3` is between 5 and +10: + +```cpp +#include <gmock/gmock.h> + +using ::testing::AllOf; +using ::testing::Gt; +using ::testing::Lt; +using ::testing::MatchesRegex; +using ::testing::StartsWith; + +... +EXPECT_THAT(value1, StartsWith("Hello")); +EXPECT_THAT(value2, MatchesRegex("Line \\d+")); +ASSERT_THAT(value3, AllOf(Gt(5), Lt(10))); +``` + +Matchers enable assertions of this form to read like English and generate +informative failure messages. For example, if the above assertion on `value1` +fails, the resulting message will be similar to the following: + +``` +Value of: value1 + Actual: "Hi, world!" +Expected: starts with "Hello" +``` + +GoogleTest provides a built-in library of matchers—see the +[Matchers Reference](matchers.md). It is also possible to write your own +matchers—see [Writing New Matchers Quickly](../gmock_cook_book.md#NewMatchers). +The use of matchers makes `EXPECT_THAT` a powerful, extensible assertion. + +*The idea for this assertion was borrowed from Joe Walnes' Hamcrest project, +which adds `assertThat()` to JUnit.* + +## Boolean Conditions {#boolean} + +The following assertions test Boolean conditions. + +### EXPECT_TRUE {#EXPECT_TRUE} + +`EXPECT_TRUE(`*`condition`*`)` \ +`ASSERT_TRUE(`*`condition`*`)` + +Verifies that *`condition`* is true. + +### EXPECT_FALSE {#EXPECT_FALSE} + +`EXPECT_FALSE(`*`condition`*`)` \ +`ASSERT_FALSE(`*`condition`*`)` + +Verifies that *`condition`* is false. + +## Binary Comparison {#binary-comparison} + +The following assertions compare two values. The value arguments must be +comparable by the assertion's comparison operator, otherwise a compiler error +will result. + +If an argument supports the `<<` operator, it will be called to print the +argument when the assertion fails. Otherwise, GoogleTest will attempt to print +them in the best way it can—see +[Teaching GoogleTest How to Print Your Values](../advanced.md#teaching-googletest-how-to-print-your-values). + +Arguments are always evaluated exactly once, so it's OK for the arguments to +have side effects. However, the argument evaluation order is undefined and +programs should not depend on any particular argument evaluation order. + +These assertions work with both narrow and wide string objects (`string` and +`wstring`). + +See also the [Floating-Point Comparison](#floating-point) assertions to compare +floating-point numbers and avoid problems caused by rounding. + +### EXPECT_EQ {#EXPECT_EQ} + +`EXPECT_EQ(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_EQ(`*`val1`*`,`*`val2`*`)` + +Verifies that *`val1`*`==`*`val2`*. + +Does pointer equality on pointers. If used on two C strings, it tests if they +are in the same memory location, not if they have the same value. Use +[`EXPECT_STREQ`](#EXPECT_STREQ) to compare C strings (e.g. `const char*`) by +value. + +When comparing a pointer to `NULL`, use `EXPECT_EQ(`*`ptr`*`, nullptr)` instead +of `EXPECT_EQ(`*`ptr`*`, NULL)`. + +### EXPECT_NE {#EXPECT_NE} + +`EXPECT_NE(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_NE(`*`val1`*`,`*`val2`*`)` + +Verifies that *`val1`*`!=`*`val2`*. + +Does pointer equality on pointers. If used on two C strings, it tests if they +are in different memory locations, not if they have different values. Use +[`EXPECT_STRNE`](#EXPECT_STRNE) to compare C strings (e.g. `const char*`) by +value. + +When comparing a pointer to `NULL`, use `EXPECT_NE(`*`ptr`*`, nullptr)` instead +of `EXPECT_NE(`*`ptr`*`, NULL)`. + +### EXPECT_LT {#EXPECT_LT} + +`EXPECT_LT(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_LT(`*`val1`*`,`*`val2`*`)` + +Verifies that *`val1`*`<`*`val2`*. + +### EXPECT_LE {#EXPECT_LE} + +`EXPECT_LE(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_LE(`*`val1`*`,`*`val2`*`)` + +Verifies that *`val1`*`<=`*`val2`*. + +### EXPECT_GT {#EXPECT_GT} + +`EXPECT_GT(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_GT(`*`val1`*`,`*`val2`*`)` + +Verifies that *`val1`*`>`*`val2`*. + +### EXPECT_GE {#EXPECT_GE} + +`EXPECT_GE(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_GE(`*`val1`*`,`*`val2`*`)` + +Verifies that *`val1`*`>=`*`val2`*. + +## String Comparison {#c-strings} + +The following assertions compare two **C strings**. To compare two `string` +objects, use [`EXPECT_EQ`](#EXPECT_EQ) or [`EXPECT_NE`](#EXPECT_NE) instead. + +These assertions also accept wide C strings (`wchar_t*`). If a comparison of two +wide strings fails, their values will be printed as UTF-8 narrow strings. + +To compare a C string with `NULL`, use `EXPECT_EQ(`*`c_string`*`, nullptr)` or +`EXPECT_NE(`*`c_string`*`, nullptr)`. + +### EXPECT_STREQ {#EXPECT_STREQ} + +`EXPECT_STREQ(`*`str1`*`,`*`str2`*`)` \ +`ASSERT_STREQ(`*`str1`*`,`*`str2`*`)` + +Verifies that the two C strings *`str1`* and *`str2`* have the same contents. + +### EXPECT_STRNE {#EXPECT_STRNE} + +`EXPECT_STRNE(`*`str1`*`,`*`str2`*`)` \ +`ASSERT_STRNE(`*`str1`*`,`*`str2`*`)` + +Verifies that the two C strings *`str1`* and *`str2`* have different contents. + +### EXPECT_STRCASEEQ {#EXPECT_STRCASEEQ} + +`EXPECT_STRCASEEQ(`*`str1`*`,`*`str2`*`)` \ +`ASSERT_STRCASEEQ(`*`str1`*`,`*`str2`*`)` + +Verifies that the two C strings *`str1`* and *`str2`* have the same contents, +ignoring case. + +### EXPECT_STRCASENE {#EXPECT_STRCASENE} + +`EXPECT_STRCASENE(`*`str1`*`,`*`str2`*`)` \ +`ASSERT_STRCASENE(`*`str1`*`,`*`str2`*`)` + +Verifies that the two C strings *`str1`* and *`str2`* have different contents, +ignoring case. + +## Floating-Point Comparison {#floating-point} + +The following assertions compare two floating-point values. + +Due to rounding errors, it is very unlikely that two floating-point values will +match exactly, so `EXPECT_EQ` is not suitable. In general, for floating-point +comparison to make sense, the user needs to carefully choose the error bound. + +GoogleTest also provides assertions that use a default error bound based on +Units in the Last Place (ULPs). To learn more about ULPs, see the article +[Comparing Floating Point Numbers](https://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/). + +### EXPECT_FLOAT_EQ {#EXPECT_FLOAT_EQ} + +`EXPECT_FLOAT_EQ(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_FLOAT_EQ(`*`val1`*`,`*`val2`*`)` + +Verifies that the two `float` values *`val1`* and *`val2`* are approximately +equal, to within 4 ULPs from each other. + +### EXPECT_DOUBLE_EQ {#EXPECT_DOUBLE_EQ} + +`EXPECT_DOUBLE_EQ(`*`val1`*`,`*`val2`*`)` \ +`ASSERT_DOUBLE_EQ(`*`val1`*`,`*`val2`*`)` + +Verifies that the two `double` values *`val1`* and *`val2`* are approximately +equal, to within 4 ULPs from each other. + +### EXPECT_NEAR {#EXPECT_NEAR} + +`EXPECT_NEAR(`*`val1`*`,`*`val2`*`,`*`abs_error`*`)` \ +`ASSERT_NEAR(`*`val1`*`,`*`val2`*`,`*`abs_error`*`)` + +Verifies that the difference between *`val1`* and *`val2`* does not exceed the +absolute error bound *`abs_error`*. + +## Exception Assertions {#exceptions} + +The following assertions verify that a piece of code throws, or does not throw, +an exception. Usage requires exceptions to be enabled in the build environment. + +Note that the piece of code under test can be a compound statement, for example: + +```cpp +EXPECT_NO_THROW({ + int n = 5; + DoSomething(&n); +}); +``` + +### EXPECT_THROW {#EXPECT_THROW} + +`EXPECT_THROW(`*`statement`*`,`*`exception_type`*`)` \ +`ASSERT_THROW(`*`statement`*`,`*`exception_type`*`)` + +Verifies that *`statement`* throws an exception of type *`exception_type`*. + +### EXPECT_ANY_THROW {#EXPECT_ANY_THROW} + +`EXPECT_ANY_THROW(`*`statement`*`)` \ +`ASSERT_ANY_THROW(`*`statement`*`)` + +Verifies that *`statement`* throws an exception of any type. + +### EXPECT_NO_THROW {#EXPECT_NO_THROW} + +`EXPECT_NO_THROW(`*`statement`*`)` \ +`ASSERT_NO_THROW(`*`statement`*`)` + +Verifies that *`statement`* does not throw any exception. + +## Predicate Assertions {#predicates} + +The following assertions enable more complex predicates to be verified while +printing a more clear failure message than if `EXPECT_TRUE` were used alone. + +### EXPECT_PRED* {#EXPECT_PRED} + +`EXPECT_PRED1(`*`pred`*`,`*`val1`*`)` \ +`EXPECT_PRED2(`*`pred`*`,`*`val1`*`,`*`val2`*`)` \ +`EXPECT_PRED3(`*`pred`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`)` \ +`EXPECT_PRED4(`*`pred`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`)` \ +`EXPECT_PRED5(`*`pred`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`,`*`val5`*`)` + +`ASSERT_PRED1(`*`pred`*`,`*`val1`*`)` \ +`ASSERT_PRED2(`*`pred`*`,`*`val1`*`,`*`val2`*`)` \ +`ASSERT_PRED3(`*`pred`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`)` \ +`ASSERT_PRED4(`*`pred`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`)` \ +`ASSERT_PRED5(`*`pred`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`,`*`val5`*`)` + +Verifies that the predicate *`pred`* returns `true` when passed the given values +as arguments. + +The parameter *`pred`* is a function or functor that accepts as many arguments +as the corresponding macro accepts values. If *`pred`* returns `true` for the +given arguments, the assertion succeeds, otherwise the assertion fails. + +When the assertion fails, it prints the value of each argument. Arguments are +always evaluated exactly once. + +As an example, see the following code: + +```cpp +// Returns true if m and n have no common divisors except 1. +bool MutuallyPrime(int m, int n) { ... } +... +const int a = 3; +const int b = 4; +const int c = 10; +... +EXPECT_PRED2(MutuallyPrime, a, b); // Succeeds +EXPECT_PRED2(MutuallyPrime, b, c); // Fails +``` + +In the above example, the first assertion succeeds, and the second fails with +the following message: + +``` +MutuallyPrime(b, c) is false, where +b is 4 +c is 10 +``` + +Note that if the given predicate is an overloaded function or a function +template, the assertion macro might not be able to determine which version to +use, and it might be necessary to explicitly specify the type of the function. +For example, for a Boolean function `IsPositive()` overloaded to take either a +single `int` or `double` argument, it would be necessary to write one of the +following: + +```cpp +EXPECT_PRED1(static_cast<bool (*)(int)>(IsPositive), 5); +EXPECT_PRED1(static_cast<bool (*)(double)>(IsPositive), 3.14); +``` + +Writing simply `EXPECT_PRED1(IsPositive, 5);` would result in a compiler error. +Similarly, to use a template function, specify the template arguments: + +```cpp +template <typename T> +bool IsNegative(T x) { + return x < 0; +} +... +EXPECT_PRED1(IsNegative<int>, -5); // Must specify type for IsNegative +``` + +If a template has multiple parameters, wrap the predicate in parentheses so the +macro arguments are parsed correctly: + +```cpp +ASSERT_PRED2((MyPredicate<int, int>), 5, 0); +``` + +### EXPECT_PRED_FORMAT* {#EXPECT_PRED_FORMAT} + +`EXPECT_PRED_FORMAT1(`*`pred_formatter`*`,`*`val1`*`)` \ +`EXPECT_PRED_FORMAT2(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`)` \ +`EXPECT_PRED_FORMAT3(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`)` \ +`EXPECT_PRED_FORMAT4(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`)` +\ +`EXPECT_PRED_FORMAT5(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`,`*`val5`*`)` + +`ASSERT_PRED_FORMAT1(`*`pred_formatter`*`,`*`val1`*`)` \ +`ASSERT_PRED_FORMAT2(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`)` \ +`ASSERT_PRED_FORMAT3(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`)` \ +`ASSERT_PRED_FORMAT4(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`)` +\ +`ASSERT_PRED_FORMAT5(`*`pred_formatter`*`,`*`val1`*`,`*`val2`*`,`*`val3`*`,`*`val4`*`,`*`val5`*`)` + +Verifies that the predicate *`pred_formatter`* succeeds when passed the given +values as arguments. + +The parameter *`pred_formatter`* is a *predicate-formatter*, which is a function +or functor with the signature: + +```cpp +testing::AssertionResult PredicateFormatter(const char* expr1, + const char* expr2, + ... + const char* exprn, + T1 val1, + T2 val2, + ... + Tn valn); +``` + +where *`val1`*, *`val2`*, ..., *`valn`* are the values of the predicate +arguments, and *`expr1`*, *`expr2`*, ..., *`exprn`* are the corresponding +expressions as they appear in the source code. The types `T1`, `T2`, ..., `Tn` +can be either value types or reference types; if an argument has type `T`, it +can be declared as either `T` or `const T&`, whichever is appropriate. For more +about the return type `testing::AssertionResult`, see +[Using a Function That Returns an AssertionResult](../advanced.md#using-a-function-that-returns-an-assertionresult). + +As an example, see the following code: + +```cpp +// Returns the smallest prime common divisor of m and n, +// or 1 when m and n are mutually prime. +int SmallestPrimeCommonDivisor(int m, int n) { ... } + +// Returns true if m and n have no common divisors except 1. +bool MutuallyPrime(int m, int n) { ... } + +// A predicate-formatter for asserting that two integers are mutually prime. +testing::AssertionResult AssertMutuallyPrime(const char* m_expr, + const char* n_expr, + int m, + int n) { + if (MutuallyPrime(m, n)) return testing::AssertionSuccess(); + + return testing::AssertionFailure() << m_expr << " and " << n_expr + << " (" << m << " and " << n << ") are not mutually prime, " + << "as they have a common divisor " << SmallestPrimeCommonDivisor(m, n); +} + +... +const int a = 3; +const int b = 4; +const int c = 10; +... +EXPECT_PRED_FORMAT2(AssertMutuallyPrime, a, b); // Succeeds +EXPECT_PRED_FORMAT2(AssertMutuallyPrime, b, c); // Fails +``` + +In the above example, the final assertion fails and the predicate-formatter +produces the following failure message: + +``` +b and c (4 and 10) are not mutually prime, as they have a common divisor 2 +``` + +## Windows HRESULT Assertions {#HRESULT} + +The following assertions test for `HRESULT` success or failure. For example: + +```cpp +CComPtr<IShellDispatch2> shell; +ASSERT_HRESULT_SUCCEEDED(shell.CoCreateInstance(L"Shell.Application")); +CComVariant empty; +ASSERT_HRESULT_SUCCEEDED(shell->ShellExecute(CComBSTR(url), empty, empty, empty, empty)); +``` + +The generated output contains the human-readable error message associated with +the returned `HRESULT` code. + +### EXPECT_HRESULT_SUCCEEDED {#EXPECT_HRESULT_SUCCEEDED} + +`EXPECT_HRESULT_SUCCEEDED(`*`expression`*`)` \ +`ASSERT_HRESULT_SUCCEEDED(`*`expression`*`)` + +Verifies that *`expression`* is a success `HRESULT`. + +### EXPECT_HRESULT_FAILED {#EXPECT_HRESULT_FAILED} + +`EXPECT_HRESULT_FAILED(`*`expression`*`)` \ +`ASSERT_HRESULT_FAILED(`*`expression`*`)` + +Verifies that *`expression`* is a failure `HRESULT`. + +## Death Assertions {#death} + +The following assertions verify that a piece of code causes the process to +terminate. For context, see [Death Tests](../advanced.md#death-tests). + +These assertions spawn a new process and execute the code under test in that +process. How that happens depends on the platform and the variable +`::testing::GTEST_FLAG(death_test_style)`, which is initialized from the +command-line flag `--gtest_death_test_style`. + +* On POSIX systems, `fork()` (or `clone()` on Linux) is used to spawn the + child, after which: + * If the variable's value is `"fast"`, the death test statement is + immediately executed. + * If the variable's value is `"threadsafe"`, the child process re-executes + the unit test binary just as it was originally invoked, but with some + extra flags to cause just the single death test under consideration to + be run. +* On Windows, the child is spawned using the `CreateProcess()` API, and + re-executes the binary to cause just the single death test under + consideration to be run - much like the `"threadsafe"` mode on POSIX. + +Other values for the variable are illegal and will cause the death test to fail. +Currently, the flag's default value is +**`"fast"`**. + +If the death test statement runs to completion without dying, the child process +will nonetheless terminate, and the assertion fails. + +Note that the piece of code under test can be a compound statement, for example: + +```cpp +EXPECT_DEATH({ + int n = 5; + DoSomething(&n); +}, "Error on line .* of DoSomething()"); +``` + +### EXPECT_DEATH {#EXPECT_DEATH} + +`EXPECT_DEATH(`*`statement`*`,`*`matcher`*`)` \ +`ASSERT_DEATH(`*`statement`*`,`*`matcher`*`)` + +Verifies that *`statement`* causes the process to terminate with a nonzero exit +status and produces `stderr` output that matches *`matcher`*. + +The parameter *`matcher`* is either a [matcher](matchers.md) for a `const +std::string&`, or a regular expression (see +[Regular Expression Syntax](../advanced.md#regular-expression-syntax))—a bare +string *`s`* (with no matcher) is treated as +[`ContainsRegex(s)`](matchers.md#string-matchers), **not** +[`Eq(s)`](matchers.md#generic-comparison). + +For example, the following code verifies that calling `DoSomething(42)` causes +the process to die with an error message that contains the text `My error`: + +```cpp +EXPECT_DEATH(DoSomething(42), "My error"); +``` + +### EXPECT_DEATH_IF_SUPPORTED {#EXPECT_DEATH_IF_SUPPORTED} + +`EXPECT_DEATH_IF_SUPPORTED(`*`statement`*`,`*`matcher`*`)` \ +`ASSERT_DEATH_IF_SUPPORTED(`*`statement`*`,`*`matcher`*`)` + +If death tests are supported, behaves the same as +[`EXPECT_DEATH`](#EXPECT_DEATH). Otherwise, verifies nothing. + +### EXPECT_DEBUG_DEATH {#EXPECT_DEBUG_DEATH} + +`EXPECT_DEBUG_DEATH(`*`statement`*`,`*`matcher`*`)` \ +`ASSERT_DEBUG_DEATH(`*`statement`*`,`*`matcher`*`)` + +In debug mode, behaves the same as [`EXPECT_DEATH`](#EXPECT_DEATH). When not in +debug mode (i.e. `NDEBUG` is defined), just executes *`statement`*. + +### EXPECT_EXIT {#EXPECT_EXIT} + +`EXPECT_EXIT(`*`statement`*`,`*`predicate`*`,`*`matcher`*`)` \ +`ASSERT_EXIT(`*`statement`*`,`*`predicate`*`,`*`matcher`*`)` + +Verifies that *`statement`* causes the process to terminate with an exit status +that satisfies *`predicate`*, and produces `stderr` output that matches +*`matcher`*. + +The parameter *`predicate`* is a function or functor that accepts an `int` exit +status and returns a `bool`. GoogleTest provides two predicates to handle common +cases: + +```cpp +// Returns true if the program exited normally with the given exit status code. +::testing::ExitedWithCode(exit_code); + +// Returns true if the program was killed by the given signal. +// Not available on Windows. +::testing::KilledBySignal(signal_number); +``` + +The parameter *`matcher`* is either a [matcher](matchers.md) for a `const +std::string&`, or a regular expression (see +[Regular Expression Syntax](../advanced.md#regular-expression-syntax))—a bare +string *`s`* (with no matcher) is treated as +[`ContainsRegex(s)`](matchers.md#string-matchers), **not** +[`Eq(s)`](matchers.md#generic-comparison). + +For example, the following code verifies that calling `NormalExit()` causes the +process to print a message containing the text `Success` to `stderr` and exit +with exit status code 0: + +```cpp +EXPECT_EXIT(NormalExit(), testing::ExitedWithCode(0), "Success"); +``` |