Testing

• Testing with fbp-spec
  • Running fbp-spec
  • Writing fbp-spec tests
• Testing with Mocha

Testing with fbp-spec

fbp-spec is a test runner designed for testing any flow-based graphs or components. It provides a way to define tests in a data-driven way, with a fixture graph, a set of input data to send to a component, and expectations on resulting output data.

• Read more: fbp-spec usage guide.

Running fbp-spec tests

To run fbp-spec tests, you need two pieces: a NoFlo runtime, and the fbp-spec test runner. Install these as development dependencies in your project:

$ npm install noflo-nodejs fpb-spec --save-dev

fbp-spec runs the tests in the following way:

1. Load all fbp-spec .yaml files from your spec/ folder
2. Start a NoFlo runtime with noflo-nodejs
3. For each test suite, start a NoFlo network, send input data, and run expectations on the results

All of the communications between fbp-spec and your NoFlo environment are done via the FBP Network Protocol meaning that they can run on different machines, tests can be executed against running NoFlo installations, and more.

However, the typical way is to use fbp-spec as the runner executed via NPM. Add it to the scripts section of your package.json:

{
  "scripts": {
    "test": "fbp-spec --secret test --address ws://localhost:3333 --command 'noflo-nodejs --port 3333 --capture-output --secret test' spec/"
  }
}

Once you have some test files in your spec/ folder, you can run them with:

$ npm test

Writing fbp-spec tests

fbp-spec tests are defined in YAML format. At its simplest, you can define a test against a component or graph by just setting the test topic. So if you have a component DoSomething, create a file spec/DoSomething.yaml with the contents:

topic: DoSomething
cases: []

When testing a basic component, you usually don’t need a fixture graph. When you define the topic, fbp-spec knows how to expose it for testing. Test cases are written by providing a sequence of input data, and then expectations on output data. The file above with two simple test cases would look like:

topic: DoSomething
cases:
-
  name: sending a boolean
  assertion: should repeat the same
  inputs:
    in: true
  expect:
    out:
     equals: true
-
  name: sending a number
  assertion: should repeat the same
  inputs:
    in: 1000
  expect:
    out:
      equals: 1000

Read more in writing fbp-spec tests.

Testing with Mocha

In addition to testing tools tailored for flow-based program testing, you can of course test NoFlo components or graphs with regular JavaScript testing frameworks like Mocha.

The easiest way to run a NoFlo component in Mocha is to use NoFlo’s asCallback method which wraps a component or graph into a simple callback function.

Here is an example:

const noflo = require('noflo');
let baseDir = 'my-project';
if (!noflo.isBrowser()) {
  // Tests are running on Node.js, load chai and set project baseDir to project root
  const chai = require('chai');
  const path = require('path');
  baseDir = path.resolve(__dirname, '../');
}

describe('My component', () => {
  // Wrap your component into a function
  let mycomp = null;
  before(() => {
    // We need to provide the name of the component/graph we're
    // testing, and the project basedir where NoFlo looks for
    // components
    mycomp = noflo.asCallback('my_project/MyComponent', {
      baseDir: baseDir,
    });
  });
  // Then run it inside your tests
  it('should add one to the data it receives', (done) => {
    mycomp(1, (err, result) => {
      // If there was an error, fail the test
      if (err) { return done(err); }
      // Test the result
      chai.expect(result).to.equal(2);
      done()
    });
  });
});