Add tests for useWindowSize

babel.config.js

@@ -0,0 +1,3 @@
+module.exports = {
+    presets: ['@babel/preset-env', '@babel/preset-react', "@babel/preset-typescript"],
+};

jest.config.js

@@ -0,0 +1,185 @@
+// For a detailed explanation regarding each configuration property, visit:
+// https://jestjs.io/docs/en/configuration.html
+
+module.exports = {
+  // All imported modules in your tests should be mocked automatically
+  // automock: false,
+
+  // Stop running tests after `n` failures
+  // bail: 0,
+
+  // Respect "browser" field in package.json when resolving modules
+  // browser: false,
+
+  // The directory where Jest should store its cached dependency information
+  // cacheDirectory: "/private/var/folders/wb/9k3h2ztj2bx49z0345wd8cyjjd68f0/T/jest_rf4s00",
+
+  // Automatically clear mock calls and instances between every test
+  clearMocks: true,
+
+  // Indicates whether the coverage information should be collected while executing the test
+  // collectCoverage: false,
+
+  // An array of glob patterns indicating a set of files for which coverage information should be collected
+  // collectCoverageFrom: null,
+
+  // The directory where Jest should output its coverage files
+  // coverageDirectory: null,
+
+  // An array of regexp pattern strings used to skip coverage collection
+  // coveragePathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // A list of reporter names that Jest uses when writing coverage reports
+  // coverageReporters: [
+  //   "json",
+  //   "text",
+  //   "lcov",
+  //   "clover"
+  // ],
+
+  // An object that configures minimum threshold enforcement for coverage results
+  // coverageThreshold: null,
+
+  // A path to a custom dependency extractor
+  // dependencyExtractor: null,
+
+  // Make calling deprecated APIs throw helpful error messages
+  // errorOnDeprecated: false,
+
+  // Force coverage collection from ignored files using an array of glob patterns
+  // forceCoverageMatch: [],
+
+  // A path to a module which exports an async function that is triggered once before all test suites
+  // globalSetup: null,
+
+  // A path to a module which exports an async function that is triggered once after all test suites
+  // globalTeardown: null,
+
+  // A set of global variables that need to be available in all test environments
+  // globals: {},
+
+  // An array of directory names to be searched recursively up from the requiring module's location
+  // moduleDirectories: [
+  //   "node_modules"
+  // ],
+
+  // An array of file extensions your modules use
+  // moduleFileExtensions: [
+  //   "js",
+  //   "json",
+  //   "jsx",
+  //   "ts",
+  //   "tsx",
+  //   "node"
+  // ],
+
+  // A map from regular expressions to module names that allow to stub out resources with a single module
+  // moduleNameMapper: {},
+
+  // An array of regexp pattern strings, matched against all module paths before considered 'visible' to the module loader
+  // modulePathIgnorePatterns: [],
+
+  // Activates notifications for test results
+  // notify: false,
+
+  // An enum that specifies notification mode. Requires { notify: true }
+  // notifyMode: "failure-change",
+
+  // A preset that is used as a base for Jest's configuration
+  // preset: null,
+
+  // Run tests from one or more projects
+  // projects: null,
+
+  // Use this configuration option to add custom reporters to Jest
+  // reporters: undefined,
+
+  // Automatically reset mock state between every test
+  // resetMocks: false,
+
+  // Reset the module registry before running each individual test
+  // resetModules: false,
+
+  // A path to a custom resolver
+  // resolver: null,
+
+  // Automatically restore mock state between every test
+  // restoreMocks: false,
+
+  // The root directory that Jest should scan for tests and modules within
+  // rootDir: null,
+
+  // A list of paths to directories that Jest should use to search for files in
+  // roots: [
+  //   "<rootDir>"
+  // ],
+
+  // Allows you to use a custom runner instead of Jest's default test runner
+  // runner: "jest-runner",
+
+  // The paths to modules that run some code to configure or set up the testing environment before each test
+  // setupFiles: [],
+
+  // A list of paths to modules that run some code to configure or set up the testing framework before each test
+  // setupFilesAfterEnv: [],
+
+  // A list of paths to snapshot serializer modules Jest should use for snapshot testing
+  // snapshotSerializers: [],
+
+  // The test environment that will be used for testing
+  // testEnvironment: "jest-environment-jsdom",
+
+  // Options that will be passed to the testEnvironment
+  // testEnvironmentOptions: {},
+
+  // Adds a location field to test results
+  // testLocationInResults: false,
+
+  // The glob patterns Jest uses to detect test files
+  // testMatch: [
+  //   "**/__tests__/**/*.[jt]s?(x)",
+  //   "**/?(*.)+(spec|test).[tj]s?(x)"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all test paths, matched tests are skipped
+  // testPathIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // The regexp pattern or array of patterns that Jest uses to detect test files
+  // testRegex: [],
+
+  // This option allows the use of a custom results processor
+  // testResultsProcessor: null,
+
+  // This option allows use of a custom test runner
+  // testRunner: "jasmine2",
+
+  // This option sets the URL for the jsdom environment. It is reflected in properties such as location.href
+  // testURL: "http://localhost",
+
+  // Setting this value to "fake" allows the use of fake timers for functions such as "setTimeout"
+  // timers: "real",
+
+  // A map from regular expressions to paths to transformers
+  // transform: null,
+
+  // An array of regexp pattern strings that are matched against all source file paths, matched files will skip transformation
+  // transformIgnorePatterns: [
+  //   "/node_modules/"
+  // ],
+
+  // An array of regexp pattern strings that are matched against all modules before the module loader will automatically return a mock for them
+  // unmockedModulePathPatterns: undefined,
+
+  // Indicates whether each individual test should be reported during the run
+  // verbose: null,
+
+  // An array of regexp patterns that are matched against all source file paths before re-running tests in watch mode
+  // watchPathIgnorePatterns: [],
+
+  // Whether to use watchman for file crawling
+  // watchman: true,
+};

package.json

@@ -12,7 +12,7 @@
   "typings": "lib/index.d.ts",
   "scripts": {
     "start": "yarn storybook",
-    "test": "echo hmm...",
+    "test": "jest",
     "build:cjs": "tsc",
     "build:es": "tsc -m esNext --outDir esm",
     "build": "yarn build:cjs && yarn build:es",
@@ -49,6 +49,9 @@
     "rebound": "*"
   },
   "devDependencies": {
+    "@babel/preset-env": "^7.4.3",
+    "@babel/preset-react": "^7.0.0",
+    "@babel/preset-typescript": "^7.3.3",
     "@semantic-release/changelog": "3.0.2",
     "@semantic-release/git": "7.0.8",
     "@semantic-release/npm": "5.1.4",
@@ -57,15 +60,18 @@
     "@storybook/addon-notes": "5.0.6",
     "@storybook/addon-options": "5.0.6",
     "@storybook/react": "5.0.6",
+    "@types/jest": "^24.0.11",
     "@types/react": "16.8.13",
     "babel-core": "6.26.3",
     "fork-ts-checker-webpack-plugin": "1.0.1",
     "gh-pages": "2.0.1",
+    "jest": "^24.7.1",
     "keyboardjs": "2.5.1",
     "markdown-loader": "5.0.0",
     "react": "16.8.4",
     "react-dom": "16.8.4",
     "react-spring": "6.1.10",
+    "react-testing-library": "^6.1.2",
     "rebound": "0.1.0",
     "rimraf": "2.6.3",
     "rxjs": "6.4.0",

src/tests/useWindowSize/container.tsx

@@ -0,0 +1,20 @@
+import * as React from "react";
+import useWindowSize from "../../useWindowSize"
+
+const WindowComponent = () => {
+  const { width, height } = useWindowSize();
+  return (
+    <div>
+      <p>
+        <span>width - </span>
+        <span data-testid="width">{width}</span>
+      </p>
+      <p>
+        <span>height - </span>
+        <span data-testid="height">{height}</span>
+      </p>
+    </div>
+  );
+}
+
+export default WindowComponent

src/tests/useWindowSize/useWindowSize.test.tsx

@@ -0,0 +1,56 @@
+import * as React from "react";
+import useWindowSize from "../../useWindowSize"
+import WindowComponent from './container'
+import { render, getByTestId } from 'react-testing-library'
+import { act } from 'react-dom/test-utils'; 
+
+// simulate window resize 
+function fireResize(type, value) {
+  switch (type) {
+    case 'width':
+      (window.innerWidth as number) = value // assert type of window.innerWidth as it is typed as readonly.
+      break;
+    case 'height':
+      (window.innerHeight as number) = value // assert type of window.innerHeight as it is typed as readonly.
+    break;
+    default:
+      break;
+  }
+  window.dispatchEvent(new Event('resize'))
+}
+
+describe("useWindowSize", () => {
+  it("should be defined", () => {
+    expect(useWindowSize).toBeDefined();
+  });
+
+  const { container, rerender } = render(<WindowComponent />)
+  const width = getByTestId(container, "width");
+  const height = getByTestId(container, "height");
+
+  it("should update width", () => {
+    act(() => {
+      fireResize('width', 320)
+      rerender(<WindowComponent />) 
+    })
+    expect(width.textContent).toBe('320')
+    act(() => {
+      fireResize('width', 640)
+      rerender(<WindowComponent />) 
+    })
+    expect(width.textContent).toBe('640')
+  });
+
+  it("should update height", () => {
+    act(() => {
+      fireResize('height', 500)
+      rerender(<WindowComponent />) 
+    })
+    expect(height.textContent).toBe('500')
+    act(() => {
+      fireResize('height', 1000)
+      rerender(<WindowComponent />) 
+    })
+    expect(height.textContent).toBe('1000')
+  });
+});