Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/electronvector/fake_function_framework

A plug-in for Ceedling to use the Fake Function Framework (fff) for mocking instead of Cmock.
https://github.com/electronvector/fake_function_framework

Last synced: 3 months ago
JSON representation

A plug-in for Ceedling to use the Fake Function Framework (fff) for mocking instead of Cmock.

Awesome Lists containing this project

README 

        
# A Fake Function Framework Plug-in for Ceedling



[![Build Status](https://travis-ci.com/ElectronVector/fake_function_framework.svg?branch=master)](https://travis-ci.com/ElectronVector/fake_function_framework)



This is a plug-in for [Ceedling](https://github.com/ThrowTheSwitch/Ceedling) to use the [Fake Function Framework](https://github.com/meekrosoft/fff) for mocking instead of CMock.



Using fff provides less strict mocking than CMock, and allows for more loosely-coupled tests.

And, when tests fail -- since you get the actual line number of the failure -- it's a lot easier to figure out what went wrong.



## Installing the plug-in



This fff plugin should already be included with your Ceedling installation, but to use it on a project you first need to enable it in your project.yml file.



### Enable the plug-in



This plug-in needs to be enabled from within your project.yml file. It is not enabled by default.



In the `:plugins` configuration, add `fake_function_framework` to the list of enabled plugins.



```yaml

:plugins:

  :enabled:

    - stdout_pretty_tests_report

    - module_generator

    - fake_function_framework # <-- Enable it here.

```



### Get the latest version of this plugin



You may want to get the latest source of this plug if the version in your Ceedling release is not up-to-date.



The easiest way to do this is to clone this repo into the Ceedling plugin folder.



Typically Ceedling is used from its gem installation folder, which is where you will want to clone this repo. You can determine where Ceedling is intalled on your machine by running:



```

$ gem list -d -e ceedling



*** LOCAL GEMS ***



ceedling (0.30.0)

    Authors: Mark VanderVoord, Michael Karlesky, Greg Williams

    Homepage: http://throwtheswitch.org/ceedling

    License: MIT

    Installed at: /var/lib/gems/2.7.0



    Ceedling is a build automation tool for C unit test suites that

    packages up Unity, CMock, and Rake-based build management

    functionality

```



In this case you would want to install in `/var/lib/gems/2.7.0/gems/ceedling-0.30.0/plugins/fake_function_framework`.



Remove any existing `fake_function_framework` folder and then clone the contents of this repo into it with (run from the `/var/lib/gems/2.7.0/gems/ceedling-0.30.0/plugins` folder):



```

git clone --recurse https://github.com/ElectronVector/fake_function_framework.git

```



This will create a new folder named `fake_function_framework` in the plugins folder.



#### Installing it somewhere else



You could also install it somewhere else on your machine and tell Ceedling where it is in the project.yml file with the `:load_paths:` setting:



```yaml

:plugins:

  :load_paths:

    - /some/other/place/for/plugins # <-- Your custom path.

  :enabled:

    - stdout_pretty_tests_report

    - module_generator

    - fake_function_framework

```



#### Using with Ceedling installed in the project



If you have an older project with Ceedling running from an installation inside of the project folder, then you'll need to clone into the project `vendor/ceedling/plugins/fake_function_framework` folder instead.



You'll also need to set the load path correctly for this situation.



```yaml

:plugins:

  :load_paths:

    - vendor/ceedling/plugins # <-- Your project plugin folder.

```



## How to use it



You use fff with Ceedling the same way you used to use CMock.

Modules can still be generated with the default module generator: `rake module:create[my_module]`.

If you want to "mock" `some_module.h` in your tests, just `#include "mock_some_module.h"`.

This creates a fake function for each of the functions defined in `some_module.h`.



The name of each fake is the original function name with an appended `_fake`.

For example, if we're generating fakes for a stack module with `push` and `pop` functions, we would have the fakes `push_fake` and `pop_fake`.

These fakes are linked into our test executable so that any time our unit under test calls `push` or `pop` our fakes are called instead.



Each of these fakes is actually a structure containing information about how the function was called, and what it might return.

We can use Unity to inspect these fakes in our tests, and verify the interactions of our units.

There is also a global structure named `fff` which we can use to check the sequence of calls.



The fakes can also be configured to return particular values, so you can exercise the unit under test however you want.



The examples below explain how to use fff to test a variety of module interactions.

Each example uses fakes for a "display" module, created from a display.h file with `#include "mock_display.h"`. The `display.h` file must exist and must contain the prototypes for the functions to be faked.



### Test that a function was called once



```c

void

test_whenTheDeviceIsReset_thenTheStatusLedIsTurnedOff()

{

    // When

    event_deviceReset();



    // Then

    TEST_ASSERT_EQUAL(1, display_turnOffStatusLed_fake.call_count);

}

```



### Test that a function was NOT called



```c

void

test_whenThePowerReadingIsLessThan5_thenTheStatusLedIsNotTurnedOn(void)

{

    // When

    event_powerReadingUpdate(4);



    // Then

    TEST_ASSERT_EQUAL(0, display_turnOnStatusLed_fake.call_count);

}

```



## Test that a single function was called with the correct argument



```c

void

test_whenTheVolumeKnobIsMaxed_thenVolumeDisplayIsSetTo11(void)

{

    // When

    event_volumeKnobMaxed();



    // Then

    TEST_ASSERT_EQUAL(1, display_setVolume_fake.call_count);

    TEST_ASSERT_EQUAL(11, display_setVolume_fake.arg0_val);

}

```



## Test that calls are made in a particular sequence



```c

void

test_whenTheModeSelectButtonIsPressed_thenTheDisplayModeIsCycled(void)

{

    // When

    event_modeSelectButtonPressed();

    event_modeSelectButtonPressed();

    event_modeSelectButtonPressed();



    // Then

    TEST_ASSERT_EQUAL_PTR((void*)display_setModeToMinimum, fff.call_history[0]);

    TEST_ASSERT_EQUAL_PTR((void*)display_setModeToMaximum, fff.call_history[1]);

    TEST_ASSERT_EQUAL_PTR((void*)display_setModeToAverage, fff.call_history[2]);

}

```



## Fake a return value from a function



```c

void

test_givenTheDisplayHasAnError_whenTheDeviceIsPoweredOn_thenTheDisplayIsPoweredDown(void)

{

    // Given

    display_isError_fake.return_val = true;



    // When

    event_devicePoweredOn();



    // Then

    TEST_ASSERT_EQUAL(1, display_powerDown_fake.call_count);

}

```



## Fake a function with a value returned by reference



```c

void

test_givenTheUserHasTypedSleep_whenItIsTimeToCheckTheKeyboard_theDisplayIsPoweredDown(void)

{

    // Given

    char mockedEntry[] = "sleep";

    void return_mock_value(char * entry, int length)

    {

        if (length > strlen(mockedEntry))

        {

            strncpy(entry, mockedEntry, length);

        }

    }

    display_getKeyboardEntry_fake.custom_fake = return_mock_value;



    // When

    event_keyboardCheckTimerExpired();



    // Then

    TEST_ASSERT_EQUAL(1, display_powerDown_fake.call_count);

}

```



## Fake a function with a function pointer parameter



```

void

test_givenNewDataIsAvailable_whenTheDisplayHasUpdated_thenTheEventIsComplete(void)

{

    // A mock function for capturing the callback handler function pointer.

    void(*registeredCallback)(void) = 0;

    void mock_display_updateData(int data, void(*callback)(void))

    {

        //Save the callback function.

        registeredCallback = callback;

    }

    display_updateData_fake.custom_fake = mock_display_updateData;



    // Given

    event_newDataAvailable(10);



    // When

    if (registeredCallback != 0)

    {

        registeredCallback();

    }



    // Then

    TEST_ASSERT_EQUAL(true, eventProcessor_isLastEventComplete());

}

```



## Helper macros



For convenience, there are also some helper macros that create new Unity-style asserts:



- `TEST_ASSERT_CALLED(function)`: Asserts that a function was called once.

- `TEST_ASSERT_NOT_CALLED(function)`: Asserts that a function was never called.

- `TEST_ASSERT_CALLED_TIMES(times, function)`: Asserts that a function was called a particular number of times.

- `TEST_ASSERT_CALLED_IN_ORDER(order, function)`: Asserts that a function was called in a particular order.



Here's how you might use one of these instead of simply checking the call_count value:



```c

void

test_whenTheDeviceIsReset_thenTheStatusLedIsTurnedOff()

{

    // When

    event_deviceReset();



    // Then

    // This how to directly use fff...

    TEST_ASSERT_EQUAL(1, display_turnOffStatusLed_fake.call_count);

    // ...and this is how to use the helper macro.

    TEST_ASSERT_CALLED(display_turnOffStatusLed);

}

```



## Test setup



All of the fake functions, and any fff global state are all reset automatically between each test.



## CMock configuration



Use still use some of the CMock configuration options for setting things like the mock prefix, and for including additional header files in the mock files.



```yaml

:cmock:

    :mock_prefix: mock_

        :includes:

            -

        :includes_h_pre_orig_header:

            -

        :includes_h_post_orig_header:

            -

        :includes_c_pre_header:

            -

        :includes_c_post_header:

```



## Plugin developer tools: Running the tests



There are unit and integration tests for the plug-in itself.

These are run with the default `rake` task.

The integration test runs the tests for the example project in examples/fff_example.



## More examples



There is an example project in examples/fff_example.

It shows how to use the plug-in with some full-size examples.