action-graph

action-graph

action-graph is a tool for automating complex tasks efficiently and predictably.

It helps you structure units of work into atomic actions that promote reuse and predictability. Born to improve integration testing it's suitable for other structured tasks, like build and deploy tooling.

Install

$ npm install --save action-graph

The idea

Actions have dependencies. The dependencies are also actions, which in turn can have their own dependencies. For example, an action to "send a message" might need to first "login", and before you can "login" you need to "open the website".

With action graph, you'd specify this with three actions: SendAMessage, Login and OpenTheWebsite. SendAMessage would depend on Login, and Login would depend on OpenTheWebsite...

OpenTheWebsite
      |
    Login
      |
 SendAMessage

If you run the SendAMessage action, action-graph will automatically run OpenTheWebsite and Login first.

If you then wanted to test "delete a message" it would also depend on "login" and "open the website". You'd create a new action, DeleteAMessage, and have it depend on Login. Your graph now looks like...

        OpenTheWebsite
              |
            Login
             / \
 SendAMessage   DeleteAMessage

Running DeleteAMessage would cause OpenAWebsite and Login to run, but not SendAMessage. This is action-graph's special sauce — it will figure out the minimum amount of work required to run an action, even with very complicated (or repeated) dependencies.

A simple example

Here's an action with no dependencies.

import { createClass } from 'action-graph';

// Calling createClass is how you make an action constructor. Pass it an object, it does the rest.
const SayHello = createClass({
    // 'run' is where the action does most of its work. The first rule is that run is passed a
    // 'state' object, where it can store information about what it has done done, and it
    // must return another state object to be passed to the next action. It can also return
    // nothing, in which case the state will be passed on as it was.
    //
    // In this case we don't do anything with state — we just log a messasge!
    run(state) {
        console.log("Hello, world!");
        return state;
    }
});

Example use

Here's an example integration test suite that will get you familiar with action-graph's API and use.

import {
  createClass,

  // run takes a 'target' action, some 'context' and an initial state to run the action-graph
  // against. It builds a 'run-path' for the target, putting dependencies in the right order,
  // and the runs each in turn.
  run
} from 'action-graph';

// Here's our first action. This action will type some text into an element, specified by the
// 'selector' property.
//
// Actions are instantiated like a class:
//
//      new Type({ selector: 'input', text: 'Hello!' })
//
const Type = createClass({
    // Props are the configurable attributes of an instance of an Action. They are used to
    // uniquely identify it (more on that later).
    getDefaultProps: function () {
        return {
            selector: undefined,
            text: undefined
        };
    },

    // Actions can choose to describe themselves with a name or descripton. This action implements
    // its own description to help debugging.
    getDescription: function () {
        return 'type ' + this.props.text + ' into ' + this.props.selector;
    },

    // Run is where most of the action's work happens. The action has a 'context' property, which
    // is unique to the use-case of action-graph. Becuase this is an integration test, the context
    // contains a reference to the 'session', used to talk to a selenium server.
    //
    // The run method is passed a 'state' object, which is where actions can store the work they've
    // done. This is useful for running assertions against, or for building on the work of
    // another action. Run *must* return a state object. It will then be passed to the next action.
    run: function (state) {
        return this.context.session
            .findDisplayedByCssSelector(this.props.selector)
            .then(elem => elem.type(this.props.text))
            .then(() => state);
    }
});

const Click = createClass({ ... });

const OpenUrl = createClass({
    getDefaultProps() {
        return {
            url: 'http://localhost:9000',
            expectedTitle: ''
        };
    },

    getDescription() {
        const { props } = this; // if you want
        return `Open ${props.get('url')}`;
    },

    run(state) {
        const { props, context: { session } } = this;
        return session
            .get(props.url)
            .then(() => session.getPageTitle())
            .then(title => {
                if (title !== props.expectedTitle) {
                    throw new Error('Title was not as expected');
                }
            })
            .then(() => state.set('currentUrl', props.url));
    },

    // 'teardown' is where you undo what 'run' did. It's optional, but you might use
    // it to close a modal window or delete temporary files. Like 'run', it takes and can return
    // a state object.
    teardown() {}
});

const SendAMessage = createClass({
    // 'getDependencies' is where an action specifies its dependencies. They are specified as
    // instances of actions, or just using the constructor.
    getDependencies() {
        const { props } = this; // if you want
        return [
            new OpenUrl({
                url: 'https://your.app',
                expectedTitle: 'My App'
            }),
            new Click({
                selector: '.new'
            }),
            new Type({
                selector: '.subject',
                text: 'The subject'
            }),
            new Type({
                selector: 'textarea',
                text: 'The message'
            }),
            new Click({
                selector: '.send'
            })
        ];
    }
});

// Actually run the action. Second argument is 'context', third is the initial state.
run(
    SendAMessage,
    { session: getSession() },
    {}
);

License

MIT