CppUTest

CppUTest unit testing and mocking framework for C/C++

More information on the project page

Slack channel: Join if link not expired

Getting Started

You'll need to do the following to get started:

Building from source (Unix-based, Cygwin, MacOS):

git clone https://github.com/cpputest/cpputest.git
cd cpputest_build
autoreconf .. -i
../configure
make

You can use make install if you want to install CppUTest system-wide.

You can also use CMake, which also works for Windows Visual Studio.

git clone https://github.com/cpputest/cpputest.git
cmake -B cpputest_build
cmake --build cpputest_build

Then to get started, you'll need to do the following:

• Add the include path to the Makefile. Something like:
  • CPPFLAGS += -I$(CPPUTEST_HOME)/include
• Add the memory leak macros to your Makefile (needed for additional debug info!). Something like:
  • CXXFLAGS += -include $(CPPUTEST_HOME)/include/CppUTest/MemoryLeakDetectorNewMacros.h
  • CFLAGS += -include $(CPPUTEST_HOME)/include/CppUTest/MemoryLeakDetectorMallocMacros.h
• Add the library linking to your Makefile. Something like:
  • LD_LIBRARIES = -L$(CPPUTEST_HOME)/lib -lCppUTest -lCppUTestExt

After this, you can write your first test:

TEST_GROUP(FirstTestGroup)
{
};

TEST(FirstTestGroup, FirstTest)
{
   FAIL("Fail me!");
}

You can build and install cpputest using vcpkg dependency manager:

$ vcpkg install cpputest (More information: https://github.com/microsoft/vcpkg)

Command line switches

• -h help, shows the latest help, including the parameters we've implemented after updating this README page.
• -v verbose, print each test name as it runs
• -r# repeat the tests some number of times, default is one, default if # is not specified is 2. This is handy if you are experiencing memory leaks related to statics and caches.
• -s# random shuffle the test execution order. # is an integer used for seeding the random number generator. # is optional, and if omitted, the seed value is chosen automatically, which results in a different order every time. The seed value is printed to console to make it possible to reproduce a previously generated execution order. Handy for detecting problems related to dependencies between tests.
• -g group only run test whose group contains the substring group
• -n name only run test whose name contains the substring name
• -f crash on fail, run the tests as normal but, when a test fails, crash rather than report the failure in the normal way

Test Macros

• TEST(group, name) - define a test
• IGNORE_TEST(group, name) - turn off the execution of a test
• TEST_GROUP(group) - Declare a test group to which certain tests belong. This will also create the link needed from another library.
• TEST_GROUP_BASE(group, base) - Same as TEST_GROUP, just use a different base class than Utest
• TEST_SETUP() - Declare a void setup method in a TEST_GROUP - this is the same as declaring void setup()
• TEST_TEARDOWN() - Declare a void setup method in a TEST_GROUP
• IMPORT_TEST_GROUP(group) - Export the name of a test group so it can be linked in from a library. Needs to be done in main.

Set up and tear down support

• Each TEST_GROUP may contain a setup and/or a teardown method.
• setup() is called prior to each TEST body and teardown() is called after the test body.

Assertion Macros

The failure of one of these macros causes the current test to immediately exit

• CHECK(boolean condition) - checks any boolean result
• CHECK_TRUE(boolean condition) - checks for true
• CHECK_FALSE(boolean condition) - checks for false
• CHECK_EQUAL(expected, actual) - checks for equality between entities using ==. So if you have a class that supports operator==() you can use this macro to compare two instances.
• STRCMP_EQUAL(expected, actual) - check const char* strings for equality using strcmp
• LONGS_EQUAL(expected, actual) - Compares two numbers
• BYTES_EQUAL(expected, actual) - Compares two numbers, eight bits wide
• POINTERS_EQUAL(expected, actual) - Compares two const void *
• DOUBLES_EQUAL(expected, actual, tolerance) - Compares two doubles within some tolerance
• ENUMS_EQUAL_INT(excepted, actual) - Compares two enums which their underlying type is int
• ENUMS_EQUAL_TYPE(underlying_type, excepted, actual) - Compares two enums which they have the same underlying type
• FAIL(text) - always fails
• TEST_EXIT - Exit the test without failure - useful for contract testing (implementing an assert fake)

Customize CHECK_EQUAL to work with your types that support operator==()

• Create the function: SimpleString StringFrom(const yourType&)

The Extensions directory has a few of these.

Building default checks with TestPlugin

• CppUTest can support extra checking functionality by inserting TestPlugins
• TestPlugin is derived from the TestPlugin class and can be inserted in the TestRegistry via the installPlugin method.
• TestPlugins can be used for, for example, system stability and resource handling like files, memory or network connection clean-up.
• In CppUTest, the memory leak detection is done via a default enabled TestPlugin

Example of a main with a TestPlugin:

int main(int ac, char** av)
{
   LogPlugin logPlugin;
   TestRegistry::getCurrentRegistry()->installPlugin(&logPlugin);
   int result = CommandLineTestRunner::RunAllTests(ac, av);
   TestRegistry::getCurrentRegistry()->resetPlugins();
   return result;
}

Memory leak detection

• A platform specific memory leak detection mechanism is provided.
• If a test fails and has allocated memory prior to the fail and that memory is not cleaned up by TearDown, a memory leak is reported. It is best to only chase memory leaks when other errors have been eliminated.
• Some code uses lazy initialization and appears to leak when it really does not (for example: gcc stringstream used to in an earlier release). One cause is that some standard library calls allocate something and do not free it until after main (or never). To find out if a memory leak is due to lazy initialization set the -r switch to run tests twice. The signature of this situation is that the first run shows leaks and the second run shows no leaks. When both runs show leaks, you have a leak to find.

How is memory leak detection implemented?

• Before setup() a memory usage checkpoint is recorded
• After teardown() another checkpoint is taken and compared to the original checkpoint
• In Visual Studio the MS debug heap capabilities are used
• For GCC a simple new/delete count is used in overridden operators new, new[], delete and delete[]

If you use some leaky code that you can't or won't fix you can tell a TEST to ignore a certain number of leaks as in this example:

TEST(MemoryLeakWarningTest, Ignore1)
{
    EXPECT_N_LEAKS(1);
    char* arrayToLeak1 = new char[100];
}

Example Main

#include "CppUTest/CommandLineTestRunner.h"

int main(int ac, char** av)
{
  return RUN_ALL_TESTS(ac, av);
}

Example Test

#include "CppUTest/TestHarness.h"
#include "ClassName.h"

TEST_GROUP(ClassName)
{
  ClassName* className;

  void setup()
  {
    className = new ClassName();
  }
  void teardown()
  {
    delete className;
  }
};

TEST(ClassName, Create)
{
  CHECK(0 != className);
  CHECK(true);
  CHECK_EQUAL(1,1);
  LONGS_EQUAL(1,1);
  DOUBLES_EQUAL(1.000, 1.001, .01);
  STRCMP_EQUAL("hello", "hello");
  FAIL("The prior tests pass, but this one doesn't");
}

There are some scripts that are helpful in creating your initial h, cpp, and Test files. See scripts/README.TXT

Conan

CppUTest is available through conan-center.

conanfile.txt

[requires]
cpputest/4.0

[generators]
cmake_find_package
cmake_paths

CMake

find_package(CppUTest REQUIRED)

add_executable(example_test ExampleTest.cpp)

target_link_libraries(example_test PRIVATE
    CppUTest::CppUTest
    CppUTest::CppUTestExt)

Integration as external CMake project

Sometimes you want to use CppUTest in your project without installing it to your system or for having control over the version you are using. This little snippet get the wanted version from GitHub and builds it as a library.

# CppUTest
include(FetchContent)
FetchContent_Declare(
    CppUTest
    GIT_REPOSITORY https://github.com/cpputest/cpputest.git
    GIT_TAG        master # or use release tag, eg. v4.0
)
# Set this to ON if you want to have the CppUTests in your project as well.
set(TESTS OFF CACHE BOOL "Switch off CppUTest Test build")
FetchContent_MakeAvailable(CppUTest)

It can be used then like so:

add_executable(run_tests UnitTest1.cpp UnitTest2.cpp)

target_link_libraries(example_test PRIVATE
    CppUTest::CppUTest
    CppUTest::CppUTestExt)