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// Copyright 2005, Google Inc.
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// The Google C++ Testing and Mocking Framework (Google Test)
//
// This file implements the AssertionResult type.
// IWYU pragma: private, include "gtest/gtest.h"
// IWYU pragma: friend gtest/.*
// IWYU pragma: friend gmock/.*
#ifndef GOOGLETEST_INCLUDE_GTEST_GTEST_ASSERTION_RESULT_H_
#define GOOGLETEST_INCLUDE_GTEST_GTEST_ASSERTION_RESULT_H_
#include <memory>
#include <ostream>
#include <string>
#include <type_traits>
#include "gtest/gtest-message.h"
#include "gtest/internal/gtest-port.h"
GTEST_DISABLE_MSC_WARNINGS_PUSH_(4251 \
/* class A needs to have dll-interface to be used by clients of class B */)
namespace testing {
// A class for indicating whether an assertion was successful. When
// the assertion wasn't successful, the AssertionResult object
// remembers a non-empty message that describes how it failed.
//
// To create an instance of this class, use one of the factory functions
// (AssertionSuccess() and AssertionFailure()).
//
// This class is useful for two purposes:
// 1. Defining predicate functions to be used with Boolean test assertions
// EXPECT_TRUE/EXPECT_FALSE and their ASSERT_ counterparts
// 2. Defining predicate-format functions to be
// used with predicate assertions (ASSERT_PRED_FORMAT*, etc).
//
// For example, if you define IsEven predicate:
//
// testing::AssertionResult IsEven(int n) {
// if ((n % 2) == 0)
// return testing::AssertionSuccess();
// else
// return testing::AssertionFailure() << n << " is odd";
// }
//
// Then the failed expectation EXPECT_TRUE(IsEven(Fib(5)))
// will print the message
//
// Value of: IsEven(Fib(5))
// Actual: false (5 is odd)
// Expected: true
//
// instead of a more opaque
//
// Value of: IsEven(Fib(5))
// Actual: false
// Expected: true
//
// in case IsEven is a simple Boolean predicate.
//
// If you expect your predicate to be reused and want to support informative
// messages in EXPECT_FALSE and ASSERT_FALSE (negative assertions show up
// about half as often as positive ones in our tests), supply messages for
// both success and failure cases:
//
// testing::AssertionResult IsEven(int n) {
// if ((n % 2) == 0)
// return testing::AssertionSuccess() << n << " is even";
// else
// return testing::AssertionFailure() << n << " is odd";
// }
//
// Then a statement EXPECT_FALSE(IsEven(Fib(6))) will print
//
// Value of: IsEven(Fib(6))
// Actual: true (8 is even)
// Expected: false
//
// NB: Predicates that support negative Boolean assertions have reduced
// performance in positive ones so be careful not to use them in tests
// that have lots (tens of thousands) of positive Boolean assertions.
//
// To use this class with EXPECT_PRED_FORMAT assertions such as:
//
// // Verifies that Foo() returns an even number.
// EXPECT_PRED_FORMAT1(IsEven, Foo());
//
// you need to define:
//
// testing::AssertionResult IsEven(const char* expr, int n) {
// if ((n % 2) == 0)
// return testing::AssertionSuccess();
// else
// return testing::AssertionFailure()
// << "Expected: " << expr << " is even\n Actual: it's " << n;
// }
//
// If Foo() returns 5, you will see the following message:
//
// Expected: Foo() is even
// Actual: it's 5
//
class GTEST_API_ AssertionResult {
public:
// Copy constructor.
// Used in EXPECT_TRUE/FALSE(assertion_result).
AssertionResult(const AssertionResult& other);
// C4800 is a level 3 warning in Visual Studio 2015 and earlier.
// This warning is not emitted in Visual Studio 2017.
// This warning is off by default starting in Visual Studio 2019 but can be
// enabled with command-line options.
#if defined(_MSC_VER) && (_MSC_VER < 1910 || _MSC_VER >= 1920)
GTEST_DISABLE_MSC_WARNINGS_PUSH_(4800 /* forcing value to bool */)
#endif
// Used in the EXPECT_TRUE/FALSE(bool_expression).
//
// T must be contextually convertible to bool.
//
// The second parameter prevents this overload from being considered if
// the argument is implicitly convertible to AssertionResult. In that case
// we want AssertionResult's copy constructor to be used.
template <typename T>
explicit AssertionResult(
const T& success,
typename std::enable_if<
!std::is_convertible<T, AssertionResult>::value>::type*
/*enabler*/
= nullptr)
: success_(success) {}
#if defined(_MSC_VER) && (_MSC_VER < 1910 || _MSC_VER >= 1920)
GTEST_DISABLE_MSC_WARNINGS_POP_()
#endif
// Assignment operator.
AssertionResult& operator=(AssertionResult other) {
swap(other);
return *this;
}
// Returns true if and only if the assertion succeeded.
operator bool() const { return success_; } // NOLINT
// Returns the assertion's negation. Used with EXPECT/ASSERT_FALSE.
AssertionResult operator!() const;
// Returns the text streamed into this AssertionResult. Test assertions
// use it when they fail (i.e., the predicate's outcome doesn't match the
// assertion's expectation). When nothing has been streamed into the
// object, returns an empty string.
const char* message() const {
return message_ != nullptr ? message_->c_str() : "";
}
// Deprecated; please use message() instead.
const char* failure_message() const { return message(); }
// Streams a custom failure message into this object.
template <typename T>
AssertionResult& operator<<(const T& value) {
AppendMessage(Message() << value);
return *this;
}
// Allows streaming basic output manipulators such as endl or flush into
// this object.
AssertionResult& operator<<(
::std::ostream& (*basic_manipulator)(::std::ostream& stream)) {
AppendMessage(Message() << basic_manipulator);
return *this;
}
private:
// Appends the contents of message to message_.
void AppendMessage(const Message& a_message) {
if (message_ == nullptr) message_ = ::std::make_unique<::std::string>();
message_->append(a_message.GetString().c_str());
}
// Swap the contents of this AssertionResult with other.
void swap(AssertionResult& other);
// Stores result of the assertion predicate.
bool success_;
// Stores the message describing the condition in case the expectation
// construct is not satisfied with the predicate's outcome.
// Referenced via a pointer to avoid taking too much stack frame space
// with test assertions.
std::unique_ptr< ::std::string> message_;
};
// Makes a successful assertion result.
GTEST_API_ AssertionResult AssertionSuccess();
// Makes a failed assertion result.
GTEST_API_ AssertionResult AssertionFailure();
// Makes a failed assertion result with the given failure message.
// Deprecated; use AssertionFailure() << msg.
GTEST_API_ AssertionResult AssertionFailure(const Message& msg);
} // namespace testing
GTEST_DISABLE_MSC_WARNINGS_POP_() // 4251
#endif // GOOGLETEST_INCLUDE_GTEST_GTEST_ASSERTION_RESULT_H_