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ArduinoCI Ruby gem (arduino_ci)

Arduino CI is a Ruby gem for executing Continuous Integration (CI) tests on an Arduino library -- both locally and as part of a service like Travis CI.

Installation In Your GitHub Project And Using Travis CI

Add a file called Gemfile (no extension) to your Arduino project:

source 'https://rubygems.org'
gem 'arduino_ci'

Next, you need this in .travis.yml

sudo: false
language: ruby
script:
   - bundle install
   - bundle exec arduino_ci_remote.rb

That's literally all there is to it on the repository side. You'll need to go to https://travis-ci.org/profile/ and enable testing for your Arduino project. Once that happens, you should be all set. The script will test all example projects of the library and all unit tests.

Note: arduino_ci_remote.rb expects to be run from the root directory of your Arduino project library.

Unit tests in test/

All .cpp files in the test/ directory of your Arduino library are assumed to contain unit tests. Each and every one will be compiled and executed on its own.

The most basic unit test file is as follows:

#include <ArduinoUnitTests.h>
#include "../do-something.h"

unittest(your_test_name)
{
  assertEqual(4, doSomething());
}

unittest_main()

This test defines one unittest (a macro provided by ArduionUnitTests.h), called your_test_name, which makes some assertions on the target library. The unittest_main() is a macro for the int main() boilerplate required for unit testing.

Using GODMODE

Complete control of the Arduino environment is available in your unit tests through a construct called GODMODE().

unittest(example_godmode_stuff)
{
  GodmodeState* state = GODMODE();   // get access to the state
  state->reset();                    // does a full reset of the state.
  state->resetClock();               //  - you can reset just the clock (to zero)
  state->resetPins();                //  - or just the pins
  state->micros = 1;                 // manually set the clock such that micros() returns 1
  state->digitalPin[4];              // tells you the commanded state of digital pin 4
  state->digitalPin[4] = HIGH;       // digitalRead(4) will now return HIGH
  state->analogPin[3];               // tells you the commanded state of analog pin 3
  state->analogPin[3] = 99;          // analogRead(3) will now return 99
}

Pin Histories

Of course, it's possible that your code might flip the bit more than once in a function. For that scenario, you may want to examine the history of a pin's commanded outputs:

unittest(pin_history)
{
  GodmodeState* state = GODMODE();
  int myPin = 3;
  state->reset();            // pin will start LOW
  digitalWrite(myPin, HIGH);
  digitalWrite(myPin, LOW);
  digitalWrite(myPin, LOW);
  digitalWrite(myPin, HIGH);
  digitalWrite(myPin, HIGH);

  assertEqual(6, state->digitalPin[1].size());
  bool expected[6] = {LOW, HIGH, LOW, LOW, HIGH, HIGH};
  bool actual[6];

  // move history queue into an array because at the moment, reading
  // the history is destructive -- it's a linked-list queue.  this
  // means that if toArray or hasElements fails, the queue will be in
  // an unknown state and you should reset it before continuing with
  // other tests
  int numMoved = state->digitalPin[myPin].toArray(actual, 6);
  assertEqual(6, numMoved);

  // verify each element
  for (int i = 0; i < 6; ++i) {
    assertEqual(expected[i], actual[i]);
  }

Pin Futures

Reading the pin more than once per function is also a possibility. In that case, we want to queue up a few values for the digitalRead or analogRead to find.

unittest(pin_read_history)
{
  GodmodeState* state = GODMODE();
  state->reset();

  int future[6] = {33, 22, 55, 11, 44, 66};
  state->analogPin[1].fromArray(future, 6);
  for (int i = 0; i < 6; ++i)
  {
    assertEqual(future[i], analogRead(1));
  }

  // for digital pins, we have the added possibility of specifying
  // a stream of input bytes encoded as ASCII
  bool bigEndian = true;
  state->digitalPin[1].fromAscii("Yo", bigEndian);

  // digitial history as serial data, big-endian
  bool expectedBits[16] = {
    0, 1, 0, 1, 1, 0, 0, 1,  // Y
    0, 1, 1, 0, 1, 1, 1, 1   // o
  };

  for (int i = 0; i < 16; ++i) {
    assertEqual(expectedBits[i], digitalRead(1));
  }
}

Serial Data

A more complicated example: working with serial port IO. Let's say I have the following function:

void smartLightswitchSerialHandler(int pin) {
  if (Serial.available() > 0) {
    int incomingByte = Serial.read();
    int val = incomingByte == '0' ? LOW : HIGH;
    Serial.print("Ack ");
    digitalWrite(pin, val);
    Serial.print(String(pin));
    Serial.print(" ");
    Serial.print((char)incomingByte);
  }
}

This function has 3 side effects: it drains the serial port's receive buffer, affects a pin, and puts data in the serial port's send buffer. Or, if the receive buffer is empty, it does nothing at all.

unittest(does_nothing_if_no_data)
{
    // configure initial state
    GodmodeState* state = GODMODE();
    int myPin = 3;
    state->serialPort[0].dataIn = "";
    state->serialPort[0].dataOut = "";
    state->digitalPin[myPin] = LOW;

    // execute action
    smartLightswitchSerialHandler(myPin);

    // assess final state
    assertEqual(LOW, state->digitalPin[myPin]);
    assertEqual("", state->serialPort[0].dataIn);
    assertEqual("", state->serialPort[0].dataOut);
}

unittest(two_flips)
{
    GodmodeState* state = GODMODE();
    int myPin = 3;
    state->serialPort[0].dataIn = "10junk";
    state->serialPort[0].dataOut = "";
    state->digitalPin[myPin] = LOW;
    smartLightswitchSerialHandler(myPin);
    assertEqual(HIGH, state->digitalPin[myPin]);
    assertEqual("0junk", state->serialPort[0].dataIn);
    assertEqual("Ack 3 1", state->serialPort[0].dataOut);

    state->serialPort[0].dataOut = "";
    smartLightswitchSerialHandler(myPin);
    assertEqual(LOW, state->digitalPin[myPin]);
    assertEqual("junk", state->serialPort[0].dataIn);
    assertEqual("Ack 3 0", state->serialPort[0].dataOut);
}

Pin History as ASCII

For additional complexity, there are some cases where you want to use a pin as a serial port. There are history functions for that too.

  int myPin = 3;

  // digitial history as serial data, big-endian
  bool bigEndian = true;
  bool binaryAscii[24] = {
    0, 1, 0, 1, 1, 0, 0, 1,  // Y
    0, 1, 1, 0, 0, 1, 0, 1,  // e
    0, 1, 1, 1, 0, 0, 1, 1   // s
  };

  // "send" these bits
  for (int i = 0; i < 24; digitalWrite(myPin, binaryAscii[i++]));

  // The first bit in the history is the initial value, which we will ignore
  int offset = 1;

  // We should be able to parse the bits as ascii
  assertEqual("Yes", state->digitalPin[myPin].toAscii(offset, bigEndian));

Instead of queueing bits as ASCII for future use with toAscii, you can send those bits directly (and immediately) to the output using outgoingFromAscii. Likewise, you can reinterpret/examine (as ASCII) the bits you have previously queued up by calling incomingToAscii on the PinHistory object.

Interactivity of "Devices" with Observers

Even pin history and input/output buffers aren't capable of testing interactive code. For example, queueing the canned responses from a serial device before the requests are even sent to it is not a sane test environment; the library under test will see the entire future waiting for it on the input pin instead of a buffer that fills and empties over time. This calls for something more complicated.

In this example, we create a simple class to emulate a Hayes modem. (For more information, dig into the DataStreamObserver code on which DeviceUsingBytes is based.

class FakeHayesModem : public DeviceUsingBytes {
  public:
    String mLast;

    FakeHayesModem() : DeviceUsingBytes() {
      mLast = "";
      addResponseLine("AT", "OK");
      addResponseLine("ATV1", "NO CARRIER");
    }
    virtual ~FakeHayesModem() {}
    virtual void onMatchInput(String output) { mLast = output; }
};

unittest(modem_hardware)
{
  GodmodeState* state = GODMODE();
  state->reset();
  FakeHayesModem m;
  m.attach(&Serial);

  Serial.write("AT\n");
  assertEqual("AT\n", state->serialPort[0].dataOut);
  assertEqual("OK\n", m.mLast);
}

Note that instead of setting mLast = output in the onMatchInput() function for test purposes, we could just as easily queue some bytes to state->serialPort[0].dataIn for the library under test to find on its next peek() or read(). Or we could execute some action on a digital or analog input pin; the possibilities are fairly endless in this regard, although you will have to define them yourself -- from scratch -- extending the DataStreamObserver class to emulate your physical device.

Overriding default build behavior

You can add .arduino-ci.yml files to the project directory (which will then apply to both test/ and examples/), as well as to the test/ directory and each example directory in examples/. All defined fields can be overridden.

You may define new platforms, or edit existing platform definitions:

platforms:
  bogo:
    board: fakeduino:beep:bogo
    package: potato:salad
    gcc:
      features:
        - omit-frame-pointer  # becomes -fomit-frame-pointer flag
      defines:
        - HAVE_THING          # becomes -DHAVE_THING flag
      warnings:
        - no-implicit         # becomes -Wno-implicit flag
      flags:
        - -foobar             # becomes -foobar flag

  zero: ~                     # undefines the `zero` board completely

  esp8266:                    # redefines the existing esp8266
    board: esp8266:esp8266:booo
    package: esp8266:esp8266
    gcc:
      features:
      defines:
      warnings:
      flags:

For your example programs, you may set external libraries to be installed and included. You may also choose the platforms on which the compilation will be attempted:

compile:
  libraries:
    - "Adafruit FONA Library"
  platforms:
    - esp8266

For your unit tests, in addition to setting specific libraries and platforms, you may filter the list of test files that are compiled and tested. This may help speed up targeted testing.

unittest:
  testfiles:
    select:
      - "*-*.*"
    reject:
      - "sam-squamsh.*"
  libraries:
    - "abc123"
    - "def456"
  platforms:
    - bogo

More Documentation

This software is in alpha. But SampleProjects/DoSomething has a decent writeup and is a good bare-bones example of all the features.

Known Problems

Author

This gem was written by Ian Katz ([email protected]) in 2018. It's released under the Apache 2.0 license.

See Also