Tests describe the behaviour of a driver and can be used to help with development. They are also useful in describing the intended usage of a driver.

For example usage, see:

Checking Values

The Engine test framework uses rspec-expectations for verifying status variables and command results returned expected values.

Helper Functions




transmit / responds

string / hex string / byte array

emulates a device sending data to the module


function_name, *arguments

calls the function requested on the module with the arguments provided


string / hex string / byte array

this is the data the driver is expected to send to the device


provides access to the result of the last executed request


provides access to the current status of the driver


emulates a connection drop followed by re-establishment


emulates a connection drop where communications have failed to be re-established


emulates connection re-establishment. Should only be called after a device_offline


times = 1

resumes the test after the specified number of ticks through the event loop



resumes the test after waiting the specified amount of time


Byebug makes it possible to

  1. Step through code one line at a time

  2. Pause the driver at some event or specified instruction, to examine the current state.

  3. Interact with the state by executing code dynamically at the breakpoint

Byebug Resources:

Running Tests

There is a rake task where you can specify the file containing the driver spec. Drivers themselves are resolved and loaded internally, as they would be in a running system.

  • rake module:test['../aca-device-modules/modules/extron/switcher/dxp_spec.rb']

To simplify the process of running tests, when using the development setup, you can run tests in the browser.

  • Your system is scanned and spec files are listed on the right

  • Selecting a spec will attempt to load the driver file

    • You will see any load errors that occur (such as syntax errors)

    • Discovery information is listed in a table

    • The test is executed in an interactive console, allowing for interactive debugging

    • Click the refresh icon to re-run the test at any point

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