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Writing Unit Tests Part 7: Writing the Tests

In this Section

In this section of the tutorial, you will write tests that make use of the helper functions youwrote in the last section of the tutorial.

Preface

For each of the tests described below, you must add the corresponding function prototype to MathReceiverTester.hpp and the corresponding test macro to main.cpp. If you can't remember how to do it, look back at the MathSender examples. After writing each test, run all the tests and make sure that they pass.

Write an ADD test

Add the following function to the Tests section of MathReceiverTester.cpp:

// In: MathReceiverTester.cpp
void MathReceiverTester ::
  testAdd()
{
    // Set the factor parameter by command
    const F32 factor = pickF32Value();
    this->setFactor(factor, ThrottleState::NOT_THROTTLED);
    // Do the add operation
    this->doMathOp(MathOp::ADD, factor);
}

Don't forget to add a function signature in MathReceiverTester.hpp.

testAdd() calls the setFactor helper function to set the factor parameter. Then it calls the doMathOp function to do a math operation.

Write a SUB test

Add the following function to the Tests section of MathReceiverTester.cpp:

// In: MathReceiverTester.cpp
void MathReceiverTester ::
  testSub()
{
    // Set the factor parameter by loading parameters
    const F32 factor = pickF32Value();
    this->paramSet_FACTOR(factor, Fw::ParamValid::VALID);
    this->component.loadParameters();
    // Do the operation
    this->doMathOp(MathOp::SUB, factor);
}

testSub() is similar to testAdd, but it shows another way to set a parameter. testAdd shows how to set a parameter by command. You can also set a parameter by initialization, as follows:

  1. Call the paramSet function as shown. This function sets the parameter value in the part of the test harness that mimics the behavior of the parameter database component.

  2. Call the loadParameters function as shown. In flight, the function loadParameters is typically called at the start of FSW to load the parameters from the database; here it loads the parameters from the test harness. There is no command to update a parameter, so parameterUpdated is not called, and no event is emitted.

As before, after setting the parameter you call doMathOp to do the operation.

Write a MUL test: This test is the same as the ADD test, except that it uses MUL instead of add.

Write a DIV test: This test is the same as the SUB test, except that it uses DIV instead of SUB.

Write a throttle test: Add the following constant definition to the top of the MathReceiverTester.cpp file:

// In: MathReceiverTester.cpp
#define CMD_SEQ 42

Write a Throttle Test

Add the following function to the "Tests" section of MathReceiverTester.cpp:

// In: MathReceiverTester.cpp
void MathReceiverTester ::
  testThrottle()
{

    // send the number of commands required to throttle the event
    // Use the autocoded value so the unit test passes if the
    // throttle value is changed
    const F32 factor = pickF32Value();
    for (
        U16 cycle = 0;
        cycle < MathReceiverComponentBase::EVENTID_FACTOR_UPDATED_THROTTLE;
        cycle++
    ) {
        this->setFactor(factor, ThrottleState::NOT_THROTTLED);
    }

    // Event should now be throttled
    this->setFactor(factor, ThrottleState::THROTTLED);

    // send the command to clear the throttle
    this->sendCmd_CLEAR_EVENT_THROTTLE(TEST_INSTANCE_ID, CMD_SEQ);
    // invoke scheduler port to dispatch message
    const U32 context = STest::Pick::any();
    this->invoke_to_schedIn(0, context);
    // verify clear event was sent
    ASSERT_EVENTS_SIZE(1);
    ASSERT_EVENTS_THROTTLE_CLEARED_SIZE(1);

    // Throttling should be cleared
    this->setFactor(factor, ThrottleState::NOT_THROTTLED);

}

Explanation

This test first loops over the throttle count, which is stored for us in the constant EVENTID_FACTOR_UPDATED_THROTTLE of the MathReceiver component base class. On each iteration, it calls setFactor. At the end of this loop, the FACTOR_UPDATED event should be throttled.

Next the test calls setFactor with a second argument of ThrottleState::THROTTLED. This code checks that the event is throttled.

Next the test sends the command CLEAR_EVENT_THROTTLE, checks for the corresponding notification event, and checks that the throttling is cleared.

Add your tests to MathReceiverTestMain.cpp so that the tests run when `fprime-util check' is called.

Here is how to include testAdd to MathReceiverTestMain.cpp. Follow this patttern to inlcude any other unit tests you wrote:

// In: MathReceiverTestMain.cpp
TEST(Nominal, AddCommand) {
    MathModule::MathReceiverTester tester;
    tester.testAdd();
}

See if your tests are working and trouble shoot any errors:

# In: MathReceiver
fprime-util check

Next: Adding Telemetry