GoogleTest Primer

Introduction: Why GoogleTest?

• GoogleTest is a C++ testing framework.
• Designed to meet Google's specific requirements for testing.
• Supports multiple platforms: Linux, Windows, Mac.
• Key beliefs about good tests:
  1. Independent and repeatable: Tests should be isolated.
  2. Organized: Tests should reflect the structure of the code.
  3. Portable and reusable: Platform-neutral.
  4. Informative: Provide detailed failure information.
  5. Focused on content: Minimize housekeeping tasks.
  6. Fast: Efficient use of resources.
• Based on xUnit architecture.

Beware of the Nomenclature

• Historical terminology in GoogleTest can be confusing:
  • "Test Case" now referred to as "Test Suite."
  • "Test" refers to what ISTQB calls "Test Case."
• API transition from TestCase to TestSuite.

Basic Concepts

• Assertions: Core statements that check conditions.
  • Outcome: Success, nonfatal failure, or fatal failure.
  • Fatal failures abort the current function.
• Tests: Built using assertions to verify code behavior.
• Test Suite: Group of tests reflecting code structure.
• Test Program: Can contain multiple test suites.

Assertions

• GoogleTest assertions are macros similar to function calls.
• Two versions:
  • ASSERT_*: Causes fatal failure, aborts the current function.
  • EXPECT_*: Causes nonfatal failure, allows function continuation.
• Custom failure messages can be provided using the << operator.
• Supports various assertions: value comparison, string checks, etc.

Simple Tests

• Defined using TEST() macro:
  • Structure: TEST(TestSuiteName, TestName) { ... }
  • Tests run independently.
• Example:
  • Factorial function tests using TEST().

Test Fixtures

• Used for tests sharing similar data/configurations:
  1. Derive a class from testing::Test.
  2. Declare objects in the class.
  3. Use SetUp() for pre-test configuration.
  4. Use TearDown() for post-test cleanup.
• Use TEST_F() to create tests with fixtures.

Invoking the Tests

• Tests registered automatically with GoogleTest.
• Run all tests with RUN_ALL_TESTS().
• Returns 0 if successful, 1 otherwise.

Writing the main() Function

• Typically not necessary to write custom main().
• Use InitGoogleTest() and RUN_ALL_TESTS() for custom setup.
• GoogleTest provides a default main() implementation.

Known Limitations

• Thread-safety depends on availability of pthreads library.
• Not thread-safe on some systems (e.g., Windows).