Basic Concepts

1. Two level of testing: TestSuite and Test.
2. Two kinds of assertion: nonfatal and fatal. The first is EXPECT_*(expr), the second is ASSERT_*(expr).
3. Two kinds of test suite: nonfixture and fixture. The first defined by TEST(SuiteName, TestName), the second defined by TEST_F(SuiteName, TestName).

Basic Usage

1. Install by system tools (such as pacman) or building from source.
2. Define the testing cases as below:

#include <gtest/gtest.h>

TEST(SuiteName, Testname) {
    // valid c++ expression/statements

    // nonfatal
    EXPECT_TRUE(1 + 1 == 2);
    EXPECT_FALSE(1 + 1 == 3) << "Oh my god!\n";

    // fatal
    ASSERT_EQ(1, 1);
    ASSERT_NE(2, 3);
}

or fixture testing as below:

#incldue <gtest/gtest>

class TestFixtureSample : ::testing::Test {
protected:
    // Some fields to help testing

    // Will be called before the real testing
    void SetUp() override {
        // do some initializing
    }

    // Will be called after the real testing
    void TearDown() override {
        // do some cleanup
    }
};

// This define class derived from `TestFixtureSample`
TEST_F(TestFixtureSample, TestName) {
    // valid c++ expression/statements

    // nonfatal
    EXPECT_TRUE(1 + 1 == 2);
    EXPECT_FALSE(1 + 1 == 3) << "Oh my god!\n";

    // fatal
    ASSERT_EQ(1, 1);
    ASSERT_NE(2, 3);
}

1. Run the gtest in main function as below:

#include <gtest/gtest.h>

int main(int argc, char * argv[]) {
    testing::InitGoogleTest(&argc, argv);
    RUN_ALL_TESTS();
    return 0;
}

1. Finally, compile all unit-test and main sources and link them to executable which run all tests.

The Basic Mechanism

• The main function call two function. The void testing::InitGoogleTest(int * argc, char ** argv) will parse and handle the input arguments. The inline int RUN_ALL_TESTS() will call the test cases registered in the static single object.
• When you define tests by TEST(test_suite_name, test_name) or TEST_F(test_suite_name, test_name), this macro will generate a class which derived from testing::Test contains the test process in specific method virtual void TestBody(), and register the Factory of Test Class, SetUp Function, TearDown Function and other information to the static single object.