Write unit tests for PassiveBuzzerHelper #358

We need to create unit tests for the PassiveBuzzerHelper class located in com.opensourcewithslu.outputdevices. This class controls a passive buzzer, which uses a pulsating AC signal to generate a tone.

Notes

• Verify that the component initializes with the correct configuration.
• Validate that the buzzer can be turned on and off.
• Validate that the frequency outputted by the buzzer can be changed.
• Test the passiveBuzzTone method to ensure it turns the buzzer on, buzzes for one second, then turns the buzzer off.
• Test that the toneIterator method turns the buzzer on, correctly plays each of its frequencies for one second each, then turns the buzzer off.
• Test that the piToneSequence method correctly turns the buzzer on plays, frequencies representing the first ten digits of pi, then turns the buzzer off.

Acceptance Criteria

• All test cases detailed above are implemented.
• Tests validate expected behavior for all methods.
• Tests validate all cases where a method should fail, and that appropriate error messages are provided.
• Tests handle edge cases.
• Tests are written using the Java JUnit Jupiter framework.
• Tests are written in the com.opensourcewithslu.outputdevices package in the pi4micronaut-utils/src/test directory.
• The Pwm class is mocked using the Mockito framework, or a similar tool.
• Tests validate that appropriate log messages are sent by each relevant method.
• All tests pass.