Add unit tests

.babelrc

@@ -0,0 +1,3 @@
+{
+  "presets": ["es2015", "react"]
+}

.gitignore

@@ -1,2 +1,3 @@
 node_modules/
 npm-debug.log
+coverage/

package.json

@@ -11,21 +11,45 @@
   "license": "MIT",
   "devDependencies": {
     "babel-cli": "^6.24.1",
+    "babel-jest": "^21.0.0",
     "babel-preset-es2015": "^6.24.1",
-    "react": "^15.6.1"
+    "babel-preset-react": "^6.24.1",
+    "enzyme": "^2.9.1",
+    "enzyme-to-json": "^1.5.1",
+    "jest": "^21.0.1",
+    "react": "^15.6.1",
+    "react-dom": "^15.6.1",
+    "react-test-renderer": "^15.6.1"
   },
   "bugs": {
     "url": "https://github.com/chrisbolin/react-detect-offline/issues"
   },
   "homepage": "https://github.com/chrisbolin/react-detect-offline#readme",
   "scripts": {
-    "compile": "babel --presets es2015 -d dist/ src/"
+    "compile": "babel src/index.js -o dist/index.js",
+    "test": "jest spec --watch",
+    "test.cover": "jest spec --coverage"
   },
   "keywords": [
     "react",
     "offline",
     "online",
     "detect",
     "disconnect"
-  ]
+  ],
+  "jest": {
+    "collectCoverageFrom": [
+      "src/**/*.js",
+      "!<rootDir>/node_modules/",
+      "!<rootDir>/demo/"
+    ],
+    "coverageThreshold": {
+      "global": {
+        "branches": 100,
+        "functions": 100,
+        "lines": 100,
+        "statements": 100
+      }
+    }
+  }
 }

src/__snapshots__/index.spec.js.snap

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+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Offline should remove event listeners when unmounting 1`] = `
+Array [
+  Array [
+    "online",
+    [Function],
+  ],
+  Array [
+    "offline",
+    [Function],
+  ],
+  Array [
+    "keydown",
+    [Function],
+  ],
+]
+`;
+
+exports[`Offline should render children when offline 1`] = `
+<Offline>
+  <h1>
+    Hello World
+  </h1>
+</Offline>
+`;
+
+exports[`Online should remove event listeners when unmounting 1`] = `
+Array [
+  Array [
+    "online",
+    [Function],
+  ],
+  Array [
+    "offline",
+    [Function],
+  ],
+  Array [
+    "keydown",
+    [Function],
+  ],
+]
+`;
+
+exports[`Online should render children when online 1`] = `
+<Online>
+  <h1>
+    Hello World
+  </h1>
+</Online>
+`;

src/index.spec.js

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+import React from 'react';
+import { mount } from 'enzyme';
+import toJSON from 'enzyme-to-json';
+import { Online, Offline } from './';
+
+const eventListenerMap = {};
+beforeEach(() => {
+  window.addEventListener = jest.fn((event, cb) => {
+    eventListenerMap[event] = cb;
+  });
+  window.removeEventListener = jest.fn(event => {
+    eventListenerMap[event] = undefined;
+  });
+});
+
+describe('Online', () => {
+  beforeEach(() => {
+    Object.defineProperty(navigator, 'onLine', {
+      configurable: true,
+      value: true
+    });
+  });
+
+  it('should render children when online', () => {
+    const wrapper = mount(
+      <Online>
+        <h1>Hello World</h1>
+      </Online>
+    );
+
+    expect(toJSON(wrapper)).toMatchSnapshot();
+  });
+
+  it('should not render children when offline', () => {
+    Object.defineProperty(navigator, 'onLine', { value: false });
+
+    const wrapper = mount(
+      <Online>
+        <h1>Hello World</h1>
+      </Online>
+    );
+
+    expect(wrapper.html()).toBeNull();
+  });
+
+  it('should not render children when going from online to offline', () => {
+    const wrapper = mount(
+      <Online>
+        <h1>Hello World</h1>
+      </Online>
+    );
+
+    eventListenerMap.offline();
+
+    expect(wrapper.html()).toBeNull();
+  });
+
+  it('should remove event listeners when unmounting', () => {
+    const wrapper = mount(
+      <Online>
+        <h1>Hello World</h1>
+      </Online>
+    );
+    wrapper.unmount();
+
+    expect(window.removeEventListener).toHaveBeenCalledTimes(3);
+    expect(window.removeEventListener.mock.calls).toMatchSnapshot();
+  });
+});
+
+describe('Offline', () => {
+  beforeEach(() => {
+    Object.defineProperty(navigator, 'onLine', {
+      configurable: true,
+      value: false
+    });
+  });
+
+  it('should render children when offline', () => {
+    const wrapper = mount(
+      <Offline>
+        <h1>Hello World</h1>
+      </Offline>
+    );
+
+    expect(toJSON(wrapper)).toMatchSnapshot();
+  });
+
+  it('should not render children when online', () => {
+    Object.defineProperty(navigator, 'onLine', { value: true });
+
+    const wrapper = mount(
+      <Offline>
+        <h1>Hello World</h1>
+      </Offline>
+    );
+
+    expect(wrapper.html()).toBeNull();
+  });
+
+  it('should not render children when going from offline to online', () => {
+    const wrapper = mount(
+      <Offline>
+        <h1>Hello World</h1>
+      </Offline>
+    );
+
+    eventListenerMap.online();
+
+    expect(wrapper.html()).toBeNull();
+  });
+
+  it('should remove event listeners when unmounting', () => {
+    const wrapper = mount(
+      <Offline>
+        <h1>Hello World</h1>
+      </Offline>
+    );
+    wrapper.unmount();
+
+    expect(window.removeEventListener).toHaveBeenCalledTimes(3);
+    expect(window.removeEventListener.mock.calls).toMatchSnapshot();
+  });
+});