Cgreen Introduction

1-cgreen_install.txt

git clone https://github.com/cgreen-devs/cgreen.git

cd cgreen
make -j4
make test
make install

# hacky fix since default install to lib64 for some reason
# open to suggestions of better solution

# append "/usr/local/lib64" to ld config
sudo vim /etc/ld.so.conf
sudo ldconfig

2-cgreen_intro.c

#include <cgreen/cgreen.h>

// What is the subject under test? SUT
// Only one per test file
Describe(ncom_message);

// Unfortunately required even if unused
BeforeEach(ncom_message)
{}

AfterEach(ncom_message)
{}

Ensure(ncom_message, is_correct_size)
{
    ncom_message test_message;

    assert_that(
            sizeof(test_message),
            is_equal_to(NCOM_MSG_SIZE) );
}

// repeat for other tests

3-cgreen_mocks.c

#include <cgreen/cgreen.h> // general unit testing
#include <cgreen/mocks.h> // mocking functionality

#include "oxts_rt_driver.h"
// Declares "oxts_rt_configure_socket" which uses "psync_socket_bind".

// Mocks and stubs help to isolate our unit tests from
// other functions, objects, and the system.

// "psync_socket_bind" is not what we are testing,
// so instead we will create a replacement mock function.

int psync_socket_bind(
        ps_socket * const sock )
{
    // "mock" is a special function that returns values
    // based on expectations provided in the tests below
    return (int)mock(sock);
}

// global test object recycled for each test
ps_socket test_socket;

Describe(oxts_socket);

BeforeEach(oxts_socket)
{
    memset( &test_socket, 0, sizeof(test_socket) );
}

AfterEach(oxts_socket)
{}

Ensure(oxts_socket, configuration_calls_bind)
{
    // expect that psync_socket_bind will be called once (no more)
    // with the socket provided and will return DTC_NONE
    expect( psync_socket_bind,
            when(sock, is_equal_to( &test_socket )),
            will_return(DTC_NONE) );
    
    assert_that(
            oxts_rt_configure_socket( &test_socket, "10.10.10.10", 1000 ),
            is_equal_to(DTC_NONE) );
}

4-Makefile

# same as all makefiles

# tests can be built as classic objects and linked
# but Cgreen provides its own convenient "cgreen-runner"
# which will find and run all Cgreen tests in a .so
TEST_RUNNER := test/test-oxts-rt-driver.so
TEST_SRCS := $(wildcard test/*.c)

test: $(TEST_RUNNER)
	cgreen-runner --colours $<

# test files are linked before libraries, which allows a mock
# version of any function in the library to be substituted
$(TEST_RUNNER): $(TEST_SRCS) $(TARGET)
	$(CC) $(CCFLAGS) $(INCLUDE) -shared -o $@ $^ $(LIBS) -lcgreen

For those of use with lenovo laptops the path /usr/local/lib/x86_64-linux-gnu/ needs to be added to /etc/ld.so.conf rather than /usr/local/lib64

Also I needed to run updatedb after install

This needs to be added to 4-Makefile:

# moc_target shared library file
MOC_TARGET  := tests/libps_neobotix_usboard_moc_driver.so

# moc-target 
$(MOC_TARGET): $(OBJS)
    $(CC) -shared $(CCFLAGS) -o $@ $^

Then revise the TEST_RUNNER target to depend on MOC_TARGET instead of TARGET