Tutorial: Create Connect IQ unit tests

In the previous tutorials we learned how to set up our project to be able to do unit testing and how to run unit tests.
To understand this article it’s rather essential that you’ve read the previous 2 articles, in case you didn’t read those articles yet I’d advise to go back and read it now, start with the article how to create a unit test project.
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Prerequisites for this tutorial

This tutorial is part of a tutorial series:

This tutorial continues where the last tutorial left of. If you did that tutorial you can continue with your own code base or you can download my project here instead.

First Unit Test: Exposing private variables

Purpose of the test

In our first actual connect IQ unit test we want to verify that the intial value of the Total Steps is set to 0.

Problem

A problem is that we need access to the total steps value to verify it, but that field is private (hidden in MonkeyC terms)…

Solution

The solution is quite easy as our mock StepsCarouselMock inherits from StepsCarouselView we can expose the private variable value in a public getter getValue(). So we add the following function to our mock:

    function getValue() {
        return value;
    }

function getValue() {

return value;

}

We now have the ability to actually get the value, now let’s go and create the actual unit test:

In the file StepsCarouselTests.mc add the code for the first test:

(:test)
function initialStepsTotalIsZero(logger) {
    var view = new StepsCarouselMock();
    var value = view.getValue();
    Toybox.Test.assertEqualMessage(value,0.0,"Initial Steps Total is expected to be 0.0");
    return true;
}

(:test)

function initialStepsTotalIsZero(logger) {

var view = new StepsCarouselMock();

var value = view.getValue();

Toybox.Test.assertEqualMessage(value,0.0,"Initial Steps Total is expected to be 0.0");

return true;

}

Ok there’s only 4 lines in our test but why are they there? Let’s go over them and explain what they do:

var view = new StepsCarouselMock(); -> create a new instance of our mocked StepsCarouselView
var value = view.getValue(); -> get the value of the field “value”, in StepsCarouselView this variable is private, but we’ve exposed it’s value in the getValue() function.
Toybox.Test.assertEqualMessage(… -> compare the actual value with the expected value and define the message to show when the test fails
return true; -> if a test function returns false then the test fails, you can misuse this functionality to do your assertions in this return statement, but personally I prefer to asserts with actual assert functions because I think it’s cleaner and more obvious when a test fails.

Run the tests

Create a run test profile for your project and execute the test, in the console window you should see the following pass by (for each watch target):

------------------------------------------------------------------------------
Executing test helloWorld...
DEBUG (21:13): Hello World
PASS
------------------------------------------------------------------------------
Executing test initialStepsTotalIsZero...
PASS

==============================================================================
RESULTS
Test:                                Status:
helloWorld                           PASS
initialStepsTotalIsZero              PASS
Ran 2 tests

PASSED
Connection Finished
Closing shell and port
Press any key to continue . . .

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

Executing test helloWorld...

DEBUG (21:13): Hello World

PASS

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

Executing test initialStepsTotalIsZero...

PASS

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

RESULTS

Test: Status:

helloWorld PASS

initialStepsTotalIsZero PASS

Ran 2 tests

PASSED

Connection Finished

Closing shell and port

Press any key to continue . . .

And also in the summary “run no evil” window you’ll see 2 succeeding tests!

Second unit test: Mock external dependencies

Purpose of the test

we want to verify that when the timer is not running that recorded steps do not increase.

Problem

The problem here that we want to test the compute function, but inside that function there is a dependency on the behaviour of an external component (Toybox.ActivityMonitor)

Solution

The solution for this issue is to replace this external dependency by something that we can access. We will in other words have to create a mock for the Toybox.ActivityMonitor and instead of calling the real one call our mock instead. In our business project we still want to call the real one though…

In the StepsCarouselView.mc file we introduce a new function getActivityMonitorInfo, this function will return the real value of the component:

    function getActivityMonitorInfo() {
        return Toybox.ActivityMonitor.getInfo();
    }

function getActivityMonitorInfo() {

return Toybox.ActivityMonitor.getInfo();

}

In the StepsCarouselView.mc file we replace the calls to Toybox.ActivityMonitor.getInfo() by a call to our newly created function. (replace in the compute function and in the onTimerStart function).

When unit testing we don’t want to depend on this external dependency

So let’s create a new mock which has the same fields as the real function.

Edit the file StepsCarouselMocks.mc and add a mock for the ActivityMonitorInfo… something like this should do it:

class ActivityMonitorInfoMock {
    var steps = 0;
    var stepGoal = 5000;
}

class ActivityMonitorInfoMock {

var steps = 0;

var stepGoal = 5000;

}

In the StepsCarouselMock we want to be able to inject the ActivityMonitorInfoMock, so let’s add the following to the StepsCarouselMock class:

    hidden var activityMonitorInfo = new ActivityMonitorInfoMock();

    function getActivityMonitorInfo() {
        return activityMonitorInfo;
    }

    function setActivityMonitorInfo (info) {
        activityMonitorInfo = info;
    }

hidden var activityMonitorInfo = new ActivityMonitorInfoMock();

function getActivityMonitorInfo() {

return activityMonitorInfo;

}

function setActivityMonitorInfo (info) {

activityMonitorInfo = info;

}

We also need to be able to get the recorded steps from the StepsCarouselMock, we learned how to do this in the first unit test, expose the private!

    function getStepsRecorded() {
        return stepsRecorded;
    }

function getStepsRecorded() {

return stepsRecorded;

}

Let’s create the unit test

Ok we’re finally ready to create the test now:

(:test)
function whenTimerDoesNotRunRecordedStepsDontIncrease(logger) {
    var view = new StepsCarouselMock();

    // create the ActivityMonitorInfoMock
    var activityMonitorInfo = new ActivityMonitorInfoMock();
    view.setActivityMonitorInfo(activityMonitorInfo);

    // set steps to 15
    activityMonitorInfo.steps = 15;
    
    // inject the ActivityMonitorInfoMock into the StepsCarouselMock
    view.setActivityMonitorInfo(activityMonitorInfo);
    
    // execute business logic
    view.compute(null);

    Toybox.Test.assertEqualMessage(activityMonitorInfo.steps,15,"Steps are 15");
    Toybox.Test.assertEqualMessage(view.getStepsRecorded(),0,"Recorded Steps are 0");

    return true;
}

(:test)

function whenTimerDoesNotRunRecordedStepsDontIncrease(logger) {

var view = new StepsCarouselMock();

// create the ActivityMonitorInfoMock

var activityMonitorInfo = new ActivityMonitorInfoMock();

view.setActivityMonitorInfo(activityMonitorInfo);

// set steps to 15

activityMonitorInfo.steps = 15;

// inject the ActivityMonitorInfoMock into the StepsCarouselMock

view.setActivityMonitorInfo(activityMonitorInfo);

// execute business logic

view.compute(null);

Toybox.Test.assertEqualMessage(activityMonitorInfo.steps,15,"Steps are 15");

Toybox.Test.assertEqualMessage(view.getStepsRecorded(),0,"Recorded Steps are 0");

return true;

}

Want some practice?

If you want some practice, try to create the following unit tests:

when the timer runs, then recorded steps should increase
when the timer is stopped, then the total steps (of the day) are shown
when the timer is stopped, then the label does not change after 5 seconds
every 5 seconds the value of the label should change (create the test + fix the bug)

Start To Run

Tutorial: Create Connect IQ unit tests

Prerequisites for this tutorial

First Unit Test: Exposing private variables

Purpose of the test

Problem

Solution

Run the tests

Second unit test: Mock external dependencies

Purpose of the test

Problem

Solution

When unit testing we don’t want to depend on this external dependency

Let’s create the unit test

Want some practice?

Source Code

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