added jest and basic tets

Author: Bryze

__tests__/index.test.jsx

@@ -0,0 +1,43 @@
+import React from 'react';
+import { mount } from 'enzyme';
+import { act } from 'react-dom/test-utils';
+import ReactTimer from '../src';
+
+test('returns correct value after 3 seconds', async () => {
+  jest.useFakeTimers();
+  const ModalWrapperComponent = mount(
+    <ReactTimer
+      start={30}
+      end={(value) => value < 25}
+      onTick={(value) => value - 1}
+    >
+      {(time) => <div>{time}</div>}
+    </ReactTimer>,
+  );
+  expect(ModalWrapperComponent.find('div').prop('children')).toEqual(30);
+  act(() => {
+    jest.advanceTimersByTime(3000);
+    ModalWrapperComponent.update();
+  });
+  expect(ModalWrapperComponent.find('div').prop('children')).toEqual(27);
+});
+
+
+test('returns correct value after reaching the end of the timer', async () => {
+  jest.useFakeTimers();
+  const ModalWrapperComponent = mount(
+    <ReactTimer
+      start={30}
+      end={(value) => value < 25}
+      onTick={(value) => value - 1}
+    >
+      {(time) => <div>{time}</div>}
+    </ReactTimer>,
+  );
+  expect(ModalWrapperComponent.find('div').prop('children')).toEqual(30);
+  act(() => {
+    jest.advanceTimersByTime(7000);
+    ModalWrapperComponent.update();
+  });
+  expect(ModalWrapperComponent.find('div').prop('children')).toEqual(24);
+});

package.json

@@ -40,7 +40,8 @@
     "docz:dev": "docz dev",
     "docz:build": "docz build",
     "docz:deploy": "yarn docz:build && gh-pages -d .docz/dist",
-    "lint:test": "yarn eslint ./src"
+    "lint:test": "yarn eslint ./src",
+    "jest": "jest"
   },
   "peerDependencies": {
     "prop-types": "^15.5.4",
@@ -54,26 +55,32 @@
     "@babel/plugin-proposal-class-properties": "^7.0.0",
     "@babel/plugin-proposal-function-bind": "^7.0.0",
     "@babel/plugin-transform-runtime": "^7.0.0",
-    "@babel/preset-env": "^7.0.0",
+    "@babel/preset-env": "^7.6.3",
     "@babel/preset-flow": "^7.0.0",
-    "@babel/preset-react": "^7.0.0",
+    "@babel/preset-react": "^7.6.3",
     "@babel/preset-stage-0": "^7.0.0",
     "@babel/preset-stage-2": "^7.0.0",
     "@svgr/rollup": "^4.3.2",
     "babel-eslint": "^10.0.1",
+    "babel-jest": "^24.9.0",
+    "babel-polyfill": "^6.26.0",
     "cross-env": "^5.1.4",
     "docz": "^2.0.0-rc.53",
+    "enzyme": "^3.10.0",
+    "enzyme-adapter-react-16": "^1.15.1",
     "eslint": "^6.2.2",
     "eslint-config-airbnb": "^18.0.1",
     "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-jsx-a11y": "^6.2.3",
     "eslint-plugin-react": "^7.16.0",
     "eslint-plugin-react-hooks": "^2.1.2",
     "gh-pages": "^2.1.1",
+    "jest": "^24.9.0",
     "react": "^16.10.2",
     "react-charts": "^2.0.0-beta.4",
     "react-dom": "^16.10.2",
     "react-live": "^2.2.1",
+    "react-test-renderer": "^16.10.2",
     "rollup": "^1.20.3",
     "rollup-plugin-babel": "^4.3.3",
     "rollup-plugin-commonjs": "^10.1.0",
@@ -84,5 +91,10 @@
   },
   "files": [
     "dist"
-  ]
+  ],
+  "jest": {
+    "setupFilesAfterEnv": [
+      "./setupTests.js"
+    ]
+  }
 }

setupTests.js

@@ -0,0 +1,5 @@
+import Enzyme from 'enzyme';
+import Adapter from 'enzyme-adapter-react-16';
+import 'babel-polyfill';
+
+Enzyme.configure({ adapter: new Adapter() });