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https://github.com/eerimoq/nala

🦁 Nala - A delightful test framework for C projects.
https://github.com/eerimoq/nala

c mocking test

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🦁 Nala - A delightful test framework for C projects.

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README 

        
|buildstatus|_

|coverage|_

|codecov|_



🦁 Nala

=======



A delightful test framework for `C` projects.



Based on `Narwhal`_ and `Narmock`_.



Features

========



- Automatic test discovery

- Use the same generic assertions everywhere

- Assertion failures reported as diffs

- Powerful mocking

- Easy-to-use output capturing utilities

- Traceback(s) on failure

- Works well with errors reported by sanitizers

- Test isolation with ``fork()``

- Only run tests matching given pattern

- Automatic build and run on file change

- Optional parallel test execution to save time

- Amalgamated source and header files ready to drop in your project

- JSON test report



Installation

============



It's recommended to install `Nala` with ``pip``. Only Python 3 is

supported.



.. code-block:: bash



   $ pip install nala



Alternatively, if mocking is not needed, you can download the

`amalgamated`_ header and source files:



- `nala.h`_

- `nala.c`_



Drop the two files in your project, make sure ``nala.c`` is compiled

and linked just like the other source files of your test program and

you should be good to go.



Getting started

===============



|tryit|_



Use ``nala init foo`` to create a folder ``foo`` with two test files,

``test_assertions.c`` and ``test_time.c``. The first uses all

assertions and captures output, and the second mocks the time

function.



.. code-block:: bash



   $ nala init foo

   Run 'make -C foo' to build and run all tests!



The assertions tests looks like this:



.. code-block:: c



   #include "nala.h"



   TEST(assertions)

   {

       int i;

       int array[] = { 1, 5, 2 };



       ASSERT_EQ(NULL, NULL);

       ASSERT_NE(1, 2);

       ASSERT_LT(1.0, 2.0);

       ASSERT_LE(1, 1);

       ASSERT_GT(2L, 1L);

       ASSERT_GE(1, 1);

       ASSERT_TRUE(true);

       ASSERT_FALSE(false);

       ASSERT_SUBSTRING("12345", "34");

       ASSERT_NOT_SUBSTRING("12345", "4567");

       ASSERT_MEMORY_EQ("abcd", "abcd", 5);

       ASSERT_FILE_EQ("test_assertions.c", "test_assertions.c");

       ASSERT_ARRAY_EQ(array, array, sizeof(array));

       ASSERT_FUNCTION_POINTER_EQ(assertions, assertions);

       ASSERT_FUNCTION_POINTER_NE(assertions, NULL);

       ASSERT(1 == 1);



       CAPTURE_OUTPUT(output, errput) {

           printf("output!\n");

           fprintf(stderr, "errput!\n");

       }



       ASSERT_EQ(output, "output!\n");

       ASSERT_EQ(errput, "errput!\n");



       for (i = 0; i < 3; i++) {

           WITH_MESSAGE("i: %d", i) {

               ASSERT_EQ(array[i], array[i]);

           }

       }

   }



And the time tests:



.. code-block:: c



   #include 

   #include "nala.h"



   TEST(mock_time)

   {

       time_mock_once(42);



       ASSERT_EQ(time(NULL), 42);

   }



Build and run all tests with ``make -s -C foo``.



.. image:: https://github.com/eerimoq/nala/raw/master/docs/build-and-run.png



Build all tests but only run those whose name contains ``time``. This

is done by giving ``ARGS=time``.



.. image:: https://github.com/eerimoq/nala/raw/master/docs/build-and-run-one-test.png



Run ``make -s -C foo auto`` to build and run all tests automatically

when any source file in your project is modified. With the command

running, make the time test fail by returning ``41`` instead of ``42``

from the time mock.



.. code-block:: c



   #include 

   #include "nala.h"



   TEST(mock_time)

   {

       time_mock_once(41);



       ASSERT_EQ(time(NULL), 42);

   }



Notice how the test is built and run automatically.



.. image:: https://github.com/eerimoq/nala/raw/master/docs/build-and-run-assert-eq-fail.png



Create a code coverage report and open it with Firefox.



.. code-block::



   $ make -s -C foo coverage

   Code coverage report: /home/erik/workspace/nala/foo/build/coverage/index.html

   $ firefox /home/erik/workspace/nala/foo/build/coverage/index.html



API

===



Below is a list of all macros and functions in the API. They are all

defined/declared in `include/nala.h`_.



Assertions

----------



.. code-block:: c



   ASSERT_EQ(actual, expected);                  // Assert that given characters, numbers, pointers or

                                                 // strings are equal.

   ASSERT_NE(actual, expected);                  // Assert that given characters, numbers, pointers or

                                                 // strings are not equal.

   ASSERT_LT(actual, expected);                  // Assert that actual is less than expected.

   ASSERT_LE(actual, expected);                  // Assert that actual is less than or equal to expected.

   ASSERT_GT(actual, expected);                  // Assert that actual is greater than expected.

   ASSERT_GE(actual, expected);                  // Assert that actual is greater than or equal to

                                                 // expected.

   ASSERT_TRUE(actual);                          // Assert that given value is true.

   ASSERT_FALSE(actual);                         // Assert that given value is false.

   ASSERT_SUBSTRING(haystack, needle);           // Assert that given haystack string contains given

                                                 // needle string.

   ASSERT_NOT_SUBSTRING(haystack, needle);       // Assert that given haystack string does not contain

                                                 // given needle string.

   ASSERT_MEMORY_EQ(actual, expected, size);     // Assert that given memory regions are equal.

   ASSERT_FILE_EQ(actual, expected);             // Assert that given files are equal.

   ASSERT_ARRAY_EQ(actual, expected, size);      // Assert that given arrays are equal.

   ASSERT_FUNCTION_POINTER_EQ(actual, expected); // Assert that given function pointers are equal.

   ASSERT_FUNCTION_POINTER_NE(actual, expected); // Assert that given function pointers are not equal.

   ASSERT(cond);                                 // Assert that given condition is true.



Other macros

------------



.. code-block:: c



   FAIL(message);                                // Fail current test with given message.

   CAPTURE_OUTPUT(stdout_name, stderr_name);     // A capture output block.

   WITH_MESSAGE(format, ...);                    // Additional message on error block. May be nested.



Functions

---------



.. code-block:: c



   void *nala_alloc(size_t size);                // Allocate a memory buffer of given size that is

                                                 // automatically freed after the test. Always returns

                                                 // a valid pointer.

   void nala_auto_free(void *buf_p);             // Automatically free given buffer after the test.

                                                 // free() is called to free the buffer.

   void nala_exit(int status);                   // Performs post-test checks and cleanup, and then

                                                 // exits with status 0. The status parameter is

                                                 // ignored.



Mocking

=======



Generating mocks

----------------



The ``nala generate_mocks`` command finds mocked functions in your

test code and generates ``nala_mocks.h``, ``nala_mocks.c`` and

``nala_mocks.ldflags``. The first two files declare and define mocks,

while the last file contains linker flags.



Use ``--rename-parameters-file`` to rename function parameters, often

useful when mocking standard library functions. If not given, Nala

renames `a few function parameters`_ by default. Also, any

``__``-prefix is removed from all parameters.



Use ``--no-rename-parameters`` not to rename any function

parameters. Overrides ``--rename-parameters-file``.



Use ``--no-implementation`` when the implementation of functions

matching given Unix shell-style wildcards pattern are not available in

the binary (and therefore should not be called by the generated code,

as the linker would give a relocation error). This option may be given

multipe times. An alternative to using this option is to manually

implement the missing functions. Here is an example implementation of

``foo()`` that makes the test fail if called.



.. code-block:: c



   int foo()

   {

       FAIL("No real implementation available!\n");



       return (0);

   }



Use ``--no-real-variadic-functions`` not to add any real variadic

functions. Nala adds `a few variadic functions`_ by default, given

that they are mocked.



Here is an example of how to generate mocks:



.. code-block:: bash



   $ nala cat *.c | gcc -DNALA_GENERATE_MOCKS -x c -E - | nala generate_mocks



``nala cat *.c`` should only concatenate test source files, not any

other source files in your project.



Nala requires test source code to be expanded by the preprocessor. You

can directly pipe the output of ``gcc -DNALA_GENERATE_MOCKS -x c -E

-`` to the command-line utility.



Mocking object-internal function calls

--------------------------------------



The GNU linker ``ld`` wrap feature (``--wrap=``) does not wrap

object-internal function calls. As Nala implements mocking by wrapping

functions, object-internal function calls can't be mocked just using

the linker. To mock these, after compilation, run ``nala

wrap_internal_symbols ...`` for each object file, and then pass them

to the linker.



Also, local (``static``) functions can't be mocked, only global

functions can!



.. code-block:: Makefile



   %.o: %.c

           $(CC) -o $@ $<

           nala wrap_internal_symbols nala_mocks.ldflags $@



Mock API

--------



A function mock will call the real implementation by default. Use the

functions below to control mock object behaviour.



Variadic functions will *not* call the real implementation by

default. Give ``--implementation`` to ``nala generate_mocks`` to

generate calls to the real function (taking a ``va_list`` instead of

``...``).



There are plenty of mock-examples in the `examples folder`_. All

inline examples below can also be found in the `mock_api_examples`_

example.



For all functions

^^^^^^^^^^^^^^^^^



```` is all char-pointer (string) and primitive type

parameters of the mocked function.



Same behaviour for every call.



.. code-block:: c



   void FUNC_mock(, );     // check parameters and return

   void FUNC_mock_ignore_in();     // ignore parameters and return

   void FUNC_mock_none();               // no calls allowed

   void FUNC_mock_implementation(*);    // replace implementation

   void FUNC_mock_real();               // real implementation



An example:



.. code-block:: c



   /* int foo(int value); */



   TEST(foo_every_call)

   {

       foo_mock(1, 2);



       /* All calls to foo() expects its parameter to be 1 and returns 2. */

       ASSERT_EQ(foo(1), 2);

       ASSERT_EQ(foo(1), 2);

   }



Per call control.



.. code-block:: c



   int FUNC_mock_once(, ); // check parameters and return once (per call)

                                        // returns a mock instance handle

   int FUNC_mock_ignore_in_once(); // ignore parameters and return once (per call)

                                        // returns a mock instance handle

   void FUNC_mock_real_once();          // real implementation once (per call)



An example:



.. code-block:: c



   /* int foo(int value); */



   TEST(foo_per_call)

   {

       foo_mock_once(1, 2);

       foo_mock_once(4, 5);



       /* First call to foo() expects its parameter to be 1 and returns 2. */

       ASSERT_EQ(foo(1), 2);



       /* Second call to foo() expects its parameter to be 4 and returns 5. */

       ASSERT_EQ(foo(4), 5);



       /* Third call will fail and the test will end. */

       foo(10);

   }



Changes the behaviour of currect mock object (most recent ``*_mock()``

or ``*_mock_once()`` call). Works for both per call and every call

functions above.



.. code-block:: c



   void FUNC_mock_set_errno(int);       // errno on return, 0 by default

   void FUNC_mock_set_callback(*);      // additional checks and/or actions

                                        // called just before returning from the mock



An example:



.. code-block:: c



   /* int foo(int value); */



   TEST(foo_set_errno)

   {

       foo_mock_once(1, 2);

       foo_mock_set_errno(EINVAL);



       ASSERT_EQ(foo(1), 2);

       ASSERT_EQ(errno, EINVAL);

   }



Get per call input parameters.



.. code-block:: c



   *FUNC_mock_get_params_in(int);       // get input parameters for given mock instance

                                        // handle



An example:



.. code-block:: c



   /* typedef void (*callback_t)(void); */

   /* void bar(callback_t callback); */



   static void fie(void)

   {

       printf("fie() called!\n");

   }



   TEST(bar_get_params_call_callback)

   {

       int handle;



       handle = bar_mock_once();



       bar(fie);



       /* Call the callback (calls fie()). */

       bar_mock_get_params_in(handle)->callback();

   }



For pointer and array function parameters

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^



Changes the behaviour of currect mock (most recent ``*_mock()`` or

``*_mock_once()`` call). Works for both per call and every call

functions above.



.. code-block:: c



   void FUNC_mock_set_PARAM_in(*, size_t);  // check on input

   void FUNC_mock_set_PARAM_in_assert(*);   // custom assert function on input

   void FUNC_mock_set_PARAM_in_pointer(*);  // check pointer (the address) on input

   void FUNC_mock_set_PARAM_out(*, size_t); // value on return

   void FUNC_mock_set_PARAM_out_copy(*);    // custom output copy function



An example:



.. code-block:: c



   /* struct foo_t { char *string_p }; */



   /* void fum(int *value_p, struct foo_t *foo_p); */



   static void assert_foo_string(struct foo_t *actual_p,

                                 struct foo_t *expected_p,

                                 size_t size)

   {

       ASSERT_EQ(size, sizeof(*expected_p));

       ASSERT_EQ(actual_p->string_p, expected_p->string_p);

   }



   TEST(fum_in_out)

   {

       int value;

       struct foo_t foo;



       fum_mock_once();



       /* Expect *value_p to be 1 when fum() is called, and assign 2 to

          it before returning. */

       value = 1;

       fum_mock_set_value_p_in(&value, sizeof(value));

       value = 2;

       fum_mock_set_value_p_out(&value, sizeof(value));



       /* Use a custom parameter assert function to check that

          foo_p->string_p is "Hello!"  when fum() is called. */

       foo.string_p = "Hello!";

       fum_mock_set_foo_p_in(&foo, sizeof(foo));

       fum_mock_set_foo_p_in_assert(assert_foo_string);



       value = 1;

       foo.string_p = "Hello!";

       fum(&value, &foo);

       ASSERT_EQ(value, 2);

   }



For function parameters part of 

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^



Changes the behaviour of currect mock object (most recent ``*_mock()``

or ``*_mock_once()`` call). Works for both per call and every call

functions above.



.. code-block:: c



   void FUNC_mock_ignore_PARAM_in();        // ignore on input



An example:



.. code-block:: c



   /* void foo(int value); */



   TEST(foo_ignore_value)

   {

       foo_mock_once(1, 2);

       foo_mock_ignore_value_in();



       ASSERT_EQ(foo(9), 2);

   }



For variadic functions

^^^^^^^^^^^^^^^^^^^^^^



Variadic function mocks are slightly different from the above. Their

parameter list is extended with a format string (``format``) and an

ellipsis (``...``), as shown below.



.. code-block:: c



   void FUNC_mock(, , format, ...);

   void FUNC_mock_once(, , format, ...);

   void FUNC_mock_ignore_in(, format);

   void FUNC_mock_ignore_in_once(, format);



The format string supports the following specifiers.



.. code-block::



   %d  - signed integer

   %u  - unsigned integer

   %ld - signed long integer

   %lu - unsigned long integer

   %p  - pointer address

   %s  - string



The ``%p`` specifier takes no value when calling the mock function,

just like pointers are not part of the mock function parameters

list. Instead, set pointers after the mock call.



.. code-block:: c



   foo_mock(3, "%d%p%s", 5, "the-string");

   foo_mock_set_va_arg_in_pointer_at(1, NULL);



The variadic parameters are controlled by index instead of name.



.. code-block:: c



   void FUNC_mock_ignore_va_arg_in_at(uint);          // ignore on input

   void FUNC_mock_set_va_arg_in_at(uint, *, size_t);  // check on input

   void FUNC_mock_set_va_arg_in_assert_at(uint, *);   // custom assert function on input

   void FUNC_mock_set_va_arg_in_pointer_at(uint, *);  // check pointer (the address) on input

   void FUNC_mock_set_va_arg_out_at(uint, *, size_t); // value on return

   void FUNC_mock_set_va_arg_out_copy_at(uint, *);    // custom output copy function



Limitations

-----------



- Structs and unions passed by value are ignored.



- ``va_list`` parameters are ignored.



- ``malloc()`` and ``free()`` can't be mocked if forking and using

  gcov. They probably can if wrapping ``__gcov_fork()`` in an

  suspend/resume-block.



- ``static`` functions can't be mocked.



- Only primitive data type members are asserted when comparing

  structs. Pointer and union members are not asserted, and probably

  never will be.



Debugging tips

==============



Nala executes each test in its own process. This means that following

the execution of a test with a debugger can be a bit tricky because

debuggers like `GDB`_ can only follow a single process at a time.



If you're using `GDB`, set a breakpoint at ``_before_fork`` and

then run the program until it stops at the breakpoint. Before

continuing the program execution, tell `GDB` to follow the forked test

process by setting ``follow-fork-mode`` to ``child``.



Below are all commands to debug the ``assertions`` test in the example

above.



.. code-block::



   $ gdb foo/build/app

   (gdb) b assertions_before_fork

   (gdb) r

   (gdb) set follow-fork-mode child

   (gdb) c



The ``gdb`` make target starts `GDB` and runs all commmands listed

above. Set the ``TEST`` make variable to the test to debug. Both

``TEST=test_assertions::assertions`` and ``TEST=assertions`` are

accepted. The test name may be partialy given, as long as it only

matches one test.



.. code-block::



   $ make -s -C foo gdb TEST=assertions



The test program takes optional arguments as below, which also can be

helpful when debugging, especially ``--print-all-calls``.



.. code-block::



   $ foo/build/app --help

   usage: foo/build/app [-h] [-v] [-c] [-a] [-r] [-f] [-j] []



   Run tests.



   positional arguments:

     test-pattern                  Only run tests matching given pattern. '^' matches

                                   the beginning and '$' matches the end of the test

                                   name.



   optional arguments:

     -h, --help                    Show this help message and exit.

     -v, --version                 Print version information.

     -c, --continue-on-failure     Continue on test failure.

     -a, --print-all-calls         Print all calls to ease debugging.

     -r, --report-json-file        JSON test report file (default: report.json).

     -f, --print-test-file-func    Print file:function for exactly one test.

     -j, --jobs                    Run given number of tests in parallel

                                   (default: 1).



Compiler flags

==============



Pass ``-no-pie -g -O0 -fsanitize=address`` to the compiler for better

error reporting.



Read more about sanitizers here: https://en.wikipedia.org/wiki/AddressSanitizer



Other unit test frameworks

==========================



Other C unit test frameworks with similar feature set as Nala.



- `CMock`_ + `Unity`_



- `cmocka`_



Ideas

=====



New set of generated parameter functions where ``_in()`` functions are

renamed to ``_in_buffer()``. New ``_in()`` functions are added,

without the size parameter. Also remove the size parameter from the

assert function, as it is seldom used.



.. code-block:: c



   void FUNC_mock_set_PARAM_in(*);                 // check on input

   void FUNC_mock_set_PARAM_in_buffer(*, size_t);  // check on input

   void FUNC_mock_set_PARAM_in_assert(*);          // custom assert function on input

   void FUNC_mock_set_PARAM_in_pointer(*);         // check pointer (the address) on input

   void FUNC_mock_set_PARAM_out(*);                // value on return

   void FUNC_mock_set_PARAM_out_buffer(*, size_t); // value on return

   void FUNC_mock_set_PARAM_out_copy(*);           // custom output copy function



An example:



.. code-block:: c



   /* struct foo_t { char *string_p }; */



   /* void fum(int *value_p, struct foo_t *foo_p); */



   static void assert_foo_string(struct foo_t *actual_p, struct foo_t *expected_p)

   {

       /* Is size is needed (which is seldom is). */

       ASSERT_EQ(nala_mock_get_param_in_size(), sizeof(*expected_p));

       ASSERT_EQ(actual_p->string_p, expected_p->string_p);

   }



   TEST(fum_in_out)

   {

       int value;

       struct foo_t foo;



       fum_mock_once();



       /* Expect *value_p to be 1 when fum() is called, and assign 2 to

          it before returning. */

       value = 1;

       fum_mock_set_value_p_in(&value);

       value = 2;

       fum_mock_set_value_p_out(&value);



       /* Use a custom parameter assert function to check that

          foo_p->string_p is "Hello!"  when fum() is called. */

       foo.string_p = "Hello!";

       fum_mock_set_foo_p_in(&foo);

       fum_mock_set_foo_p_in_assert(assert_foo_string);



       value = 1;

       foo.string_p = "Hello!";

       fum(&value, &foo);

       ASSERT_EQ(value, 2);

   }



.. |buildstatus| image:: https://travis-ci.org/eerimoq/nala.svg?branch=master

.. _buildstatus: https://travis-ci.org/eerimoq/nala



.. |coverage| image:: https://coveralls.io/repos/github/eerimoq/nala/badge.svg?branch=master

.. _coverage: https://coveralls.io/github/eerimoq/nala



.. |codecov| image:: https://codecov.io/gh/eerimoq/nala/branch/master/graph/badge.svg

.. _codecov: https://codecov.io/gh/eerimoq/nala



.. _Narwhal: https://github.com/vberlier/narwhal

.. _Narmock: https://github.com/vberlier/narmock



.. |tryit| image:: https://img.shields.io/badge/try-online-f34b7d.svg

.. _tryit: https://repl.it/@eerimoq/nala



.. _amalgamated: https://sqlite.org/amalgamation.html

.. _nala.h: https://raw.githubusercontent.com/eerimoq/nala/master/nala/dist/nala.h

.. _nala.c: https://raw.githubusercontent.com/eerimoq/nala/master/nala/dist/nala.c



.. _a few function parameters: https://github.com/eerimoq/nala/blob/master/nala/rename_parameters.txt



.. _a few variadic functions: https://github.com/eerimoq/nala/blob/master/nala/real_variadic_functions.c



.. _include/nala.h: https://github.com/eerimoq/nala/blob/master/include/nala.h



.. _GDB: https://www.gnu.org/software/gdb/



.. _CMock: https://github.com/ThrowTheSwitch/CMock



.. _Unity: https://github.com/ThrowTheSwitch/Unity



.. _cmocka: https://cmocka.org/



.. _examples folder: https://github.com/eerimoq/nala/tree/master/examples



.. _mock_api_examples: https://github.com/eerimoq/nala/tree/master/examples/mock_api_examples