Mocking library for Arduino

1

Hello, I’m searching mocking library for Arduino. I need something like fakeit or gmock, but compatible with Arduino.

2

The official PlatformIO + Arduino mocking example uses the ArduinoFake library which is exactly based on FakeIt. This repo is also referenced in the PIO Unit Testing – Project Examples section.

3

I tried to setup fakeIt, but I got an error: can’t open “functional” file(dependency of “single_header/standalone/fakeit.hpp”) I think that I can’t because I think that fakeit was written for native platform.

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Platformie.ini: I put this line into build_flags: -I"${PROJECT_LIBDEPS_DIR}/FakeIt/"

4

You should use the ArduinoFake library as intended in Unit test mode and through ArduinoFake.h

which auto-includes FakeIt

The raw FakeIt library (GitHub - eranpeer/FakeIt: C++ mocking made easy. A simple yet very expressive, headers only library for c++ mocking.) is not PlatformIO-ready since it has a non-standard folder structure (include file is in a folder called single_header) and there’s no library.json.

5

If I recreate the above mocking example with platformio.ini

[env:native]
platform = native
build_flags = -std=gnu++11
lib_deps =
    ArduinoFake

and test\test_main.cpp (not in src/) with

#include <Arduino.h> //redirects to ArduinoFake.h in this case
#include <unity.h>
#include <string>
#include <fakeit/fakeit.hpp>

using namespace fakeit;

void setUp(void)
{
    ArduinoFakeReset();
}

struct SomeInterface {
	virtual int foo(int) = 0;
	virtual int bar(std::string) = 0;
};

void test_func_expected_pass(void)
{
    Mock<SomeInterface> mock;
    When(Method(mock,foo)).Return(0);
    SomeInterface &i = mock.get();
    // Production code
    i.foo(1);
    // Verify method mock.foo was invoked with specific arguments.
    Verify(Method(mock,foo).Using(1));
}

void test_func_expected_fail(void)
{
    Mock<SomeInterface> mock;
    When(Method(mock,foo)).Return(0);
    SomeInterface &i = mock.get();
    // Production code
    i.foo(2);
    // Verify method mock.foo was invoked with specific arguments.
    Verify(Method(mock,foo).Using(1));
}

int main(int argc, char **argv)
{
    UNITY_BEGIN();

    RUN_TEST(test_func_expected_pass);
    RUN_TEST(test_func_expected_fail);

    return UNITY_END();
}

I can use FakeIt directly and the results are as expected (1 pass, 1 fail) when using Advanced -> Test.

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6

So Fakeit work only in native environment(in platformo)?

7

You want to run ArduinoFake or FakeIt on an embedded device?

8

Yes, I want to run FakiIt on an embedded device. I want to mock Serial, because I don’t want to connect external device to print something to serial.

10

I see, this is a bit more complicated. To get the embedded device running nicely without doing laberous startup-work yourself one should use framework = arduino, but then the Serial implementation is there and likely can’t be mocked anymore without conflicting with the real implementation – one may work around this by using a either baremetal framework or a different framework that does not include Arduino, and then include ArduinoFake (with lib_compat_mode turned off) to pull in the Arduino mocks. What exact microcontroller are you running on?

11

Arduino Uno/nano. In my code I inject serial object to class that use it, so that is not big problem I think.