Data-driven FBP component/graph testing tool

fbp, bdd, fbp-protocol, tdd, test-runner, testing
npm install fbp-spec@0.6.6


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A runtime-independent test framework for Flow Based Programming (FBP) component and graphs, using declarative, data-driven testing.

One can use fbp-spec to do testing at multiple levels, each approximately corresponding to the different architectural levels of Flow Based Programming:

  • Unit (FBP component/subgraph)
  • Integration (FBP graph)
  • System (FBP runtime)


In production

Purpose & Scope

Note: fbp-spec is intended for use by application and component-library developers.

The following is considered out-of-scope:

  • Testing conformance with the FBP protocol. Instead use fbp-protocol
  • Testing an FBP runtime/engine itself. Instead use a testing framework for your particular runtime language/environment.


The MIT license



Set up fbp-spec as an NPM dependency

npm install --save-dev fbp-spec

or, install it globally. Useful if you just want the commandline tool.

npm install -g fbp-spec

Writing tests

Each declared test suite loads an FBP component (or graph) fixture, and runs a set of test cases by sending a set of input data to input ports and verifying the output data against the expected results.

name: "Simple example of passing tests"
topic: "core/Repeat"
 type: 'fbp'
 data: |
  it(core/Repeat) OUT -> IN f(core/Repeat)

  name: 'sending a boolean'
  assertion: 'should repeat the same'
    in: true
      equals: true
  name: 'sending a number'
  assertion: 'should repeat the same'
    in: 1000
      equals: 1000

Multiple ports

You can send data to multiple inports and check expectations on multiple ports per testcase:

  name: '1 active track toggled high'
  assertion: 'should give value1 color'
    tracks: 1
    animation: [
      0, # track idx
      "0xEE00EE", # val0
      "0xAA00AA", # val1
      200, # period
      50, # dutycycle
      0, # offset
      500 ] # duration
    clock: 250
     equals: 250
     equals: [0, 0x00AA] # FIXME: truncated

Sequence of packets

For testing components with state, you can sending multiple input packets in sequence.

  name: 'sequence of data using spacy notation'
  assertion: 'should pass'
      in: true
      in: false
        equals: true
        equals: false 

Extract data using path

With path you can specify a JSONPath to extract the piece(s) of data the assertions will be ran against:

  name: 'select single value'
  assertion: 'should pass'
    in: { outer: { inner: { foo: 'bar' } } }
      path: '$'
      equals: 'bar'
  name: 'selecting many correct values'
  assertion: 'should pass'
        first: { foo: 'bar' }
        second: { foo: 'bar' }
      path: '$.outer.*.foo'
      equals: 'bar'

Skipping tests

Setting skip property on a testcase or suite, will cause it to not be ran. Should contain a message of the reason for skipping.

  name: 'a test that is skipped'
  assertion: 'will not be ran'
    in: 1000
      equals: 1000
  skip: 'not implemented yet'

Using fixtures

One can use testing-specific components in the fixture, to simplify driving the unit under test with complex inputs and performing complex assertions.

 type: 'fbp'
 data: |

  generate(test/GenerateTestImage) OUT -> IN testee(my/Component)
  testee OUT -> ACTUAL compare(test/CompareImage)
  reference(test/ReadReferenceImage) OUT -> REFERENCE compare
  name: 'testing complex data with custom components fixture'
  assertion: 'should pass'
    name: someimage
    param: 100
    reference: someimage-100-result
      above: 0.99

Supported assertions

Instead of equals you can use any of the supported assertion predicates. Examples include:


For a full set of assertions, see the schema


A comprehensive set of examples can be found under ./examples. For the detailed definition of the dataformat for tests, see schemata/.

Running tests with fbp-spec commandline tool

The simplest and most universal way of running tests is with the fbp-spec commandline tool.

$ fbp-spec --address ws://localhost:3333 examples/multisuite-failandpass.yaml

MultiSuite, failing tests
  sending a boolean with wrong expect
    should fail: ✗ Error: expected true to deeply equal false
  sending a number with wrong expect
    should fail: ✗ Error: expected 1000 to deeply equal 1003
MultiSuite, passing tests
  sending a boolean
    should repeat the same: ✓
  sending a number
    should repeat the same: ✓

The --command options can be used to specify a command which will start the runtime under test:

fbp-spec --command "python2 protocol-examples/python/"

It sets the exit status to non-zero on failure, so is suitable for integrating into a Makefile or similar.

Running tests by integrating with Mocha

Mocha iss a popular test runner framework for JavaScript/CoffeeScript on browser and node.js.

Since fbp-spec communicates with your runtime over a network protocol, you can use this also when your project is not JavaScript-based. The Mocha runner is for instance used in microflo-core to test C++ components for microcontrollers & embedded devices.

You can have your fbp-spec tests run in Mocha by calling the function, in a file which is executed with the standard Mocha runner. Eg. mocha --reporter spec tests/fbpspecs.js

// fbpspecs.js
fbpspec = require('fbp-spec');

rt = {
  protocol: "websocket",
  address: "ws://localhost:3569",
  secret: "py3k", // Optional. If needed to connect/authenticate to runtime
  command: 'python2 protocol-examples/python/' // Optional. Can be used to start runtime automatically
};, './examples/simple-passing.yaml', { starttimeout: 1000 });

The tests can be specified as a list of files, or directories. You can use the standard grep option of Mocha to run only some tests.

For CoffeScript example, see ./spec/

Running tests interactively in Flowhub

Flowhub IDE (version 0.11 and later) has integrated support for fbp-spec. No installation is required.

  • Open existing project, or create a new one
  • Open a component, and write/copypaste in a test in the Tests panel
  • Ensure you have a runtime set up, and connected

When you make changes to your project (components,graphs) or tests, Flowhub will now automatically (re-)run your tests. You can see the status in the top-right corner. Clicking on it brings up more details.

Generating tests programatically

The test-format defined by fbp-spec is fairly generic and versatile. It is intended primarily as a format one directly specifies tests in, but can also be generated from other sources.

Sometimes data-driven testing, one does a large amount of very similar tests, with multiple test-cases per set of input data. By capturing only the unique parts of testcases in a specialied data-structure (JSON, YAML, etc), and then transforming this into standard fbp-spec files with some code, adding/removing cases becomes even easier. For instance in imgflo-server, testcases can be defined by providing a name, an URL and a reference result (a file with naming convention based on name).

Similarly, one can generate testcases using fuzzing, schema-based, model-based or similar tools.

Integrating test runner in an application

The test runner code is accessible as a JavaScript library, and can be integrated into other apps (like Flowhub does). See examples of commandline and webappp usage.

Add supporting for a new runtime

You need to implement the FBP network protocol. At least the protocol:runtime, protocol:graph, and protocol:network capabilities are required.

All transports supported by fbp-protocol-client are supported by fbp-spec, including WebSocket, WebRTC, and iframe/postMessage.

fbp-spec is intended to be used with flow-based and dataflow-programming, but might be useful also outside these programming paradigms. Try it out!

Writing a test runner in another language

As long as you stay compatible with the fbp-spec testformat and FBP protocol, you can implement a compatible runner in any programming language.

You can consider the fbp-spec code (in CoffeeScript) as a reference implementation.