reducer-tester

reducer tester

See how-to-test-reducers

Install

$ yarn add --dev reducer-tester

Usage

// reducer.js
export const initialState = { count: 0, other: 'other' }

export default (state = initialState, action) => {
  switch (action.type) {
    case 'inc':
      return { ...state, count: state.count + 1 }
    case 'dec':
      return { ...state, count: state.count - 1 }
    default:
      return state
  }
}

// reducer.test.js
import reducerTester from 'reducer-tester'
import reducer, { initialState } from './reducer'

reducerTester({
  reducer,
  state: initialState,
  tests: [{ type: 'inc' }, { type: 'dec' }],
})

Snapshot

// Jest Snapshot v1, https://goo.gl/fbAQLP

exports[`handle initial state 1`] = `
"Snapshot Diff:
Compared values have no visual difference."
`;

exports[`dec 1`] = `
"Snapshot Diff:
- Before
+ After

  Object {
-   "count": 0,
+   "count": -1,
    "other": "other",
  }"
`;

exports[`inc 1`] = `
"Snapshot Diff:
- Before
+ After

  Object {
-   "count": 0,
+   "count": 1,
    "other": "other",
  }
`;

Full example

import reducerTester from 'reducer-tester'
import reducer, { initialState } from './reducer'

reducerTester({
  reducer, // #required
  state: initialState, // #required
  tests: [{ type: 'inc' }, { type: 'dec' }], // #required
  initialTest: false, // # optional, default: true
  titlePrefix: 'handle ', // # optional, default: ''
})

// Jest Snapshot v1, https://goo.gl/fbAQLP

exports[`handle dec 1`] = `
"Snapshot Diff:
- Before
+ After

  Object {
-   "count: 0,
+   count: -1,
  }
`;

exports[`handle inc 1`] = `
"Snapshot Diff:
- Before
+ After

  Object {
-   count: 0,
+   count: 1,
  }
`;

Tips

Atom Editor User

Install language-diff and file-types. And open config.json and edit as blow.

"*":
  "file-types":
    "\\.js\\.snap$": "source.diff"

Hooray! Very readable!

Contributors

Thanks goes to these wonderful people (emoji key):

This project follows the all-contributors specification. Contributions of any kind welcome!

License

MIT © akameco