Introduction

It is sometimes useful to have integration tests run on an embedded device while development is ongoing. This project implements the Cucumber wire protocol to direct Cucumber step invocations over a serial port so that they run on the target device under test.

It allows you to use the native Cucumber gem to execute your scripts on your development machine, and executes their steps in a server process that redirects the command execution requests to a serial port to which you connect your target device.

The components

The block diagram shows the components and their interaction:

Only so much magic supplied...

Whle the gateway portion is generic, the RPC server portion show here was written for the NRF51. This means that unless you have one, half of this project will not work for you. To port it to your embedded device, you'd need to change the main() in RPC to open and interact accordingly with your device's UART.

Customising the RPC Server

The RPC Server runs on the device and needs to be customised to your needs. Its intended use is to drive on-board integration tests, so handling the received requests and executing the test suites needs to be defined by you. In order to customise the messaging protocol and execution parameters, you need to change the following two files:

On the server side:

wire-server/api.c - This file contains the step-definition literals that you want to support. Change the entries in the api_table array. Here, specify the steps' text as well as the pointers to the functions that will execute once that step is invoked by Cucumber.

So change this:

APITable api_table[] = {
      { "I have a red led",     i_have_a_red_led    }
    , { "I turn it on",         i_turn_it_on        }
    , { "it's lit up",          it_is_lit_up        }
    , 0
};

to suit your needs.

Still in this file, implement the functions that will be called when its corresponding step is invoked by Cucumber. An example:

static int i_have_a_red_led(struct wire_context *context)
{
    char buff[20];

    serial_write(context->serialPortHandle, "EXEC 0\r");
    serial_read(context->serialPortHandle, buff, sizeof(buff));
	return(*buff == '0' ? 0 : 1);
}

This will send "EXEC 0" to the device. Decide on your protocol and change accordingly.

On the device side:

In nrf51-rpc-server/api.c, change the execution to call the needed APIs under tests:

Change:

char *api_handler(char *command)
{
    if(strstr(command, "0")) {
        nrf_gpio_pin_clear(RED);
        nrf_gpio_pin_set(GREEN);
        return("0\n");
    }

    if(strstr(command, "1")) {      // Turn on red
        nrf_gpio_pin_clear(GREEN);
        nrf_gpio_pin_set(RED);
        return("0\n");
    }

    if(strstr(command, "2")) {  // Check that red is on
        return(nrf_gpio_pin_read(RED) ? "0\n" : "1\n");
    }
    return("1\n");
}

to suit your needs.

Building the components

Building the wire-server

cd wire-server
rake

Building the RPC Serever

cd nrf51-rpc-server
make

Don't forget to flash your device with your modified code. You can use flash.sh

Running the wire-server

Plug the target device into your USB port and issue

ls /dev to see the port name assigned to it.

Use that port name as the first parameter, the second being the port number to listen on. This has to match the port number lisetd in the features/step_definitions/cucumber.wire file.

cd wire-server
./bin/wire.out /dev/tty.usbmodem1411 3901

This will start the server and you will see logs as it receives commands from the Cucumber gem.

Running the RPC Server

It will automatically run, as soon as the device is plugged into the USB port as it will execute main() on powerup.

Example Cucumber script

Feature: Hello World

	Scenario: Blink red LED
		Given I have a red led
		When I turn it on
		Then it's lit up

Running example

The Cuke:

The server logs and the RPC replying (in red):

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Code of conduct

Our code of conduct is here.

License

MIT. However, Nordic Semiconductor license applies to any NRF51 code used here.