Set up unit tests with jest and add a few tests (react-grid-layout#442)

Author: nikolas

__tests__/utils-test.js

@@ -0,0 +1,47 @@
+import {bottom, collides, validateLayout} from '../lib/utils.js';
+
+describe('bottom', () => {
+  it('Handles an empty layout as input', () => {
+    expect(bottom([])).toBe(0);
+  });
+
+  it('Returns the bottom coordinate of the layout', () => {
+    expect(bottom([
+      {x: 0, y: 1, w: 1, h: 1},
+      {x: 1, y: 2, w: 1, h: 1}
+    ])).toBe(3);
+  });
+});
+
+describe('collides', () => {
+  it('Returns whether the layout items collide', () => {
+    expect(collides(
+      {x: 0, y: 1, w: 1, h: 1},
+      {x: 1, y: 2, w: 1, h: 1}
+    )).toBe(false);
+    expect(collides(
+      {x: 0, y: 1, w: 1, h: 1},
+      {x: 0, y: 1, w: 1, h: 1}
+    )).toBe(true);
+  });
+});
+
+describe('validateLayout', () => {
+  it('Validates an empty layout', () => {
+    validateLayout([]);
+  });
+  it('Validates a populated layout', () => {
+    validateLayout([
+      {x: 0, y: 1, w: 1, h: 1},
+      {x: 1, y: 2, w: 1, h: 1}
+    ]);
+  });
+  it('Throws errors on invalid input', () => {
+    expect(() => {
+      validateLayout([
+        {x: 0, y: 1, w: 1, h: 1},
+        {x: 1, y: 2, w: 1}
+      ]);
+    }).toThrowError('Layout[1].h must be a number!');
+  });
+});

package.json

@@ -5,7 +5,7 @@
   "main": "index.js",
   "scripts": {
     "lint": "make lint",
-    "test": "echo \"Error: no test specified\" && exit 1",
+    "test": "jest",
     "build": "make build",
     "build-example": "make build-example",
     "dev": "make dev",
@@ -45,6 +45,7 @@
     "babel-cli": "^6.5.1",
     "babel-core": "^6.x",
     "babel-eslint": "^7.1.1",
+    "babel-jest": "^17.0.2",
     "babel-loader": "^6.x",
     "babel-plugin-react-transform": "^2.0.0",
     "babel-plugin-transform-react-constant-elements": "^6.5.0",
@@ -60,6 +61,7 @@
     "eslint-plugin-react": "^6.8.0",
     "exports-loader": "^0.6.3",
     "imports-loader": "^0.6.5",
+    "jest-cli": "^17.0.3",
     "jsxhint": "^0.15.1",
     "lodash": "^4.3.0",
     "pre-commit": "^1.1.2",