15_testing

Lesson 15 — Testing

What you'll learn

How to set up a make test target that compiles and runs a test suite, with the build failing if any test fails.

The pattern

test: $(TEST_TARGET)
	@echo "Running tests..."
	@./$(TEST_TARGET)

If the test binary exits with a non-zero status (test failure), Make reports an error and stops. This makes it safe to use in CI: make test returns a non-zero exit code on failure.

Three build commands

Command	What it does
make	Build the app only (default target)
make test	Build the test binary and run it
make all	Build both app and test binaries (but don't run tests)

Test framework

This lesson uses a minimal homemade test framework — no external dependencies. Three assertion macros:

ASSERT_EQ(actual, expected)     // equality check
ASSERT_TRUE(expr)               // boolean check
ASSERT_THROWS(expr)             // expects an exception

Each test is a plain function. Failures print the file, line, and values. The main() function runs all tests and returns 1 if any failed.

For real projects, you'd use a framework like Catch2 or Google Test. The Makefile structure is the same — only the test source code changes.

The code under test

A header-only Stack<T> template with push(), pop(), top(), empty(), size(). The tests verify LIFO ordering, size tracking, and that empty-stack operations throw.

Try it

cd 15_testing
make test           # builds and runs 5 tests
make                # builds just the app
./build/app         # top: 30, pop: 30, size: 2
make all            # builds both app and test binary
make clean

Files

File	Purpose
include/stack.hpp	Header-only Stack<T> template
src/main.cpp	Demo app using the stack
tests/test_stack.cpp	5 tests with custom assertion macros
Makefile	all, test, and clean targets