Integration Tests

The last level of tests that a Rock/Syskit system supports is the one of integration or acceptance tests. In a nutshell, these tests see your system as a blackbox, run actions and verify the result of these actions. They actually act as outsiders: they run everything through Syskit's remote interface, the way you would control it through the IDE or a GUI. These tests are based on Cucumber. This documentation assumes that you've at least read the introductory Cucumber material, especially the description of the guerkin language.

This page will instead focus on the Syskit-specific parts of using cucumber.

Generally speaking, each cucumber feature when interacting with a Syskit system follows this pattern:

  • start a Gazebo scene
  • start the Syskit app
  • start action(s)
  • run a predicate that verifies the action's result
  • start more action(s)
  • run more predicates that verifies the action's result
  • end

The predicates described above are themselves actions, which are supposed to finish successfully if the predicate passes, and fail otherwise.

Let's go through the items step-by-step. We will take use the Syskit basics tutorial as a basis for our examples.

Setting up a Syskit app to use integration tests

In order to use Cucumber to run test features, one needs to depend on the cucumber bundle. Just add the following in your bundle's manifest.xml, and then run aup.

<depend_optional name="bundles/cucumber" />

Add this dependency as optional, as it will allow you to exclude it from the build in production systems

You must have also followed the modifications to config/init.rb listed in the basics section,

Finally, create the initial scaffold.

  1. run cucumber --init in your bundle

  2. edit features/support/env.rb and add the Roby, RockGazebo and this bundle's own World modules to the Cucumber world.

    require 'cucumber/rock_world'
  3. create an action that refines the Cucumber action interface provided by bundles/cucumber. The refinement is meant to provide the robot-under test to the underlying compositions See bundles/cucumber/models/actions/cucumber.rb for the interface definition. The action interface is usually called Actions::Cucumber as well. In the syskit_basics bundle we created during the Basics tutorials, one would do

    syskit gen action cucumber

    and edit models/actions/cucumber.rb:

    require 'cucumber/models/actions/cucumber'
    require 'syskit_basics/models/profiles/gazebo/base'
    module SyskitBasics
        module Actions
            class Cucumber < Cucumber::Actions::Cucumber
                def cucumber_robot_model
                    # NOTE the device must be the root model, i.e. cannot use ur10_dev
  4. create a robot configuration and load this new profile in it. This robot configuration will usually "derive" from the gazebo configuration by adding the following line at the top of the robot's configuration file. This robot is commonly called cucumber.

    Create the new configuration with

    syskit gen robot cucumber

    And add the following line at the top of config/robots/cucumber.rb:

    require_relative './gazebo'

    The robot should obviously add the Cucumber action interface to its main actions, with

    Robot.requires do
        require 'syskit_basics/models/actions/cucumber'
    Robot.actions do
        use_library SyskitBasics::Actions::Cucumber

Starting the scene and the app

The app and the scene (Gazebo) are both started with a Given step of the form

Given the _robot name_ robot starting at _pose_ in _scene name_

The robot name is the name of the robot configuration in the Syskit app. The pose stanza defines where the robot-under-test should be placed in the scene at the beginning of the test (see below for how poses are specified). The scene name is the name of the scene in scenes/. Underscores in the robot or scene names can be replaced by spaces, and the can be added in front of the scene name

For instance, in our syskit_basics bundle, with the cucumber robot we just started, this could be:

Given the cucumber robot starting at origin in the empty world

If your Syskit app needs more arguments (as passed with the --set option on the command line), these can be given with a with key=value, key=value and key=value syntax. For instance

Given the cucumber robot starting at origin in the empty world with never_fail=true

Let's create now a file with the .feature extension within features/, that contains this Given line. This file will allow us to test that the setup is functioning as expected.

For instance, features/01. Test Setup.feature with:

Feature: Checking the Syskit/Cucumber Test Setup
    Scenario: Starting a simulation and a Syskit app under Cucumber
        Given the cucumber robot starting at origin in the empty world
        Then the pose reaches z=0m with a tolerance of 0.1m within 30s

Which you would run with

cucumber "features/01. Test Setup.feature"

Given/When/Then with Syskit apps

The Given/When/Then loop, when testing a Syskit app is based on placing the robot somewhere, and then using Syskit's actions to (1) do something and (2) verify the action result. The Syskit-specific Cucumber steps are only there to integrate this within a Cucumber feature file.

The Cucumber bundle provide actions and steps that allow to check the system's position. The underlying infrastructure can be used to create new steps, more adapted to your application.

More specifically, in a Cucumber scenario, one will have: - When steps that start one or more application actions, that is the actions of the application-under test. - Then steps that start zero or more monitoring actions. These actions are started in the background, and should emit their failed event when the predicate their represent fails. - Then steps that runs a predicate action, which will emit success if the test passes, and failed if not.

The application, monitoring and predicate actions of consecutive When and Then statements are batched together and started when the first predicate action is encountered. Application actions are then kept until the next When it runs ... step, while monitoring actions are dropped at the end of the predicate:

Given the cucumber robot ...
When it runs actionA # starts actionA
Then the pose is maintained at ... # starts a maintain_pose monitor
And after 10s # waits 10 seconds, starts the pending actions
# At this point, the maintain_pose monitor is stopped
# actionA is still active
Then it is failed within 20s
# actionA is still active
When it runs actionB
# actionA will be dropped in the next batch
# actionB will be used to replace it
Then after 20s # this transitions from actionA to actionB and waits 20s

In addition, a set of Given steps can be given before the app startup to initialize it with a set of actions.

For instance, let's test the syskit_basics cartesian movement:

Feature: cartesian movement
    Scenario: moving the tip of the arm to a given target
        # Start safe_robot_position_def on app startup
        Given the safe robot position definition running
        # Start the app and the simulation
        And the cucumber robot starting at origin in the empty world
        # When I start an application action with arguments
        When it runs the move arm to pose action with position={x=0.5, y=0 and z=0.5} and orientation={yaw=0, pitch=0 and roll=0}
        # Then I expect this step to match
        Then the link ur10::wrist_3 reaches x=0.5m, y=0m, z=0.5m with a tolerance of 0.01m within 20s

Note: the When step above do not match what is in our tutorial application. The Cucumber interface only allows passing simple arguments to the actions. We will therefore have to create a simple action in the Cucumber interface that translates this simple representation into the underlying action's real arguments.

Let's import the Gazebo ArmControl profile first

require 'syskit_basics/models/profiles/gazebo/arm_control

and define this helper action

describe('moves the tip of the arm to a given pose').
    required_arg(:position, 'the position as a Hash with x, y and z keys').
    required_arg(:orientation, 'the orientation as a Hash with yaw, pitch and roll keys')
def move_arm_to_pose(position:, orientation:
        position:*position.values_at(0, 0, 0),
        orientation: Eigen::Quaternion.from_euler(
  *orientation.values_at(:yaw, :pitch, :roll))))

Existing Steps

The steps are defined in the Cucumber bundle, under lib/cucumber/rock_steps.rb. The rest of this page will try to explain how these work. It will then detail how can create your own.

All names (scene, robot, actions, events, …) can be written replacing the underscore by a space, to make the steps more natural. For instance, the empty_world scene can be referred to by empty world

Given the $action action running
Given the $action action running with arg0=$arg0, arg1=$arg1 and arg2=$arg2
Given the $definition definition running
Given the $definition definition running with $arguments

Specify a set of actions and definitions that will be started in the next Given statement that starts an app. Best is to use the And keyword to chain them, and also to use And to start the app afterwards. The with versions can be used to pass arguments (see the Specifying Arguments section below)

Given the $robot_name starting at $pose in $scene
Given the $robot_name starting at $pose in $scene with $arguments

Starts the rock-gazebo and Syskit apps on the given scene and robot configuration. How $pose can be specified is detailed later. Previous Given the $action action running and Given the $definition definition running steps are started immediately. The with version can be used to pass arguments (see the Specifying Arguments section below)

When it runs the $action action
When it runs the $action action with $arguments
When it runs the $definition definition
When it runs the $definition definition with $arguments

Start an action or definition. The with version can be used to pass arguments (see the Specifying Arguments section below). The definition version appends _def to the definition name, for clarity of the step. I.e. instead of writing When it runs the arm safe joint position def action, one writes When it runs the arm safe joint position definition

Multiple actions can be started by chaining them with And.

Then the pose is maintained at $pose with a tolerance of $tolerance
Then the pose is maintained during $time at $pose with a tolerance of $tolerance

Verify that the pose is within a given tolerance of a target pose. In the first form, without the time specification, it starts a monitor that runs in the background until the next step finishes. In the seconf form, with the time, it verifies that the constraint is met during the given time. See this section for details on how $pose and $tolerance should be written.

Then after $time

Wait a given time before executing the next step. It executes the current batch (start new application actions and drops obsolete ones, runs monitor actions). See this section for details on how $pose and $tolerance should be written.

Then the pose reaches $pose with a tolerance of $tolerance within $time

Verifies that the robot reaches the given pose with tolerance in less than a given time. See this section for details on how $pose, $tolerance and $time should be written.

Then it stays there for $time

Verifies that robot stays at the pose last specified by the Then the pose reaches ... step for a given amount of time.

Then it has $event within $time
Then it is $event within $time

Verifies that the job last started with When it runs ... emits the given event within a certain amount of time. The choice between the two versions is meant to help having a clearer step (i.e. one would use it has reached target but it is aborted).

Specifying Arguments

Arguments are always specified using the form arg0=val0, arg1=val1 and arg2=val2. The value can either be a plain string, a number, or a hash of the form {key0=val0, key1=val1 and key2=val2}. Units can also be specified

Specifying Quantities

The default Cucumber steps will recognize units for certain type of quantities: length, angles and time. Moreover, it provides a specific syntax to specify constraints on positions, orientations or poses. Units are used within the built-in steps to verify that the quantities are matching what the step expects (e.g. no angles for lengths).

Lengths have a m suffix (for "meter"), e.g. 10m or 0.01m

Angles have a deg suffix (for "degrees"). Angles are internally converted to radians before being passed to the underlying action.

Times have either a h, min or s suffix (for "hours", "minutes" and *"seconds"). Fraction of a time are specified for the chosen unit (e.g. 1.5h is one and a half hour, not one hour and five minutes). They can't be combined: the system won't recognize 1h5min. They are internally converted to seconds, as a Float.

Positions are specified by providing x, y and z as lengths (m) using the argument syntax, e.g. x=10m, y=20m and z=0.2m.

Orientations are specified as Euler angles yaw, pitch and roll as angles (deg) using the argument syntax, e.g. yaw=10deg, pitch=-5deg and roll=0deg.

Poses are simply a position and an orientation specified together, that is e.g. x=10m, y=20m, z=0.2m, yaw=10deg, pitch=-5deg and roll=0deg.

Position, Orientation and Pose Constraints Constraints are specified as the target quantity followed by within a tolerance of $tolerance, where $tolerance is specified the same way. Constraints can be partial. For instance: x=10m and y=20m within a tolerance of x=0.1m and y=0.02m

Variable names can be omitted in $tolerance, in which case they are assumed to follow the same order than the target quantity: x=10m and y=20m within a tolerance of 0.1m and 0.02m

Finally, one can give a single value if all the values in the target are of the same dimension: x=10m and y=20m within a tolerance of 0.1m

Defining your own Steps

The first step to create your own steps is to follow the standard Cucumber workflow: create a .rb file in features/step_definitions and add Given, When, … definitions.

If you would like to use the argument or quantity parsing used by the default steps, they are available on the Roby::App::CucumberHelpers module.

The job management API is defined on Roby::App::Cucumber::Controller. You want in particular to have a look at the #start_job and #start_monitoring_job methods.