JS Unit Testing

docs/development/js/js-unit-test-example/src/component.js

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+import math_mod from "./math.js";
+
+export default class Component {
+
+  /**
+   * Pass dependency to math module in constructor
+   * @param math
+   */
+  constructor(math) {
+    this.math = math || math_mod;
+  }
+
+  calculate(a,b) {
+    return this.math.sum(a,b);
+  }
+}

docs/development/js/js-unit-test-example/src/math.js

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+export default {
+  sum: function(a,b) {
+    return a + b;
+  }
+}

docs/development/js/js-unit-test-example/test/component.test.js

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+import Component from '../src/component.js';
+import { expect } from 'chai';
+
+// test 1
+describe('component', function() {
+
+  let c = new Component();
+
+  it('calculate without mock', function () {
+    expect(c.calculate(1, 2)).to.equal(3);
+  });
+});
+
+// test 2
+describe('component', function() {
+
+  // pass mock as dependency
+  const mathMock = {
+    sum: (a, b) => {
+      return a + b;
+    }
+  };
+
+  let c = new Component(mathMock);
+
+  it('calculate with mock', function () {
+    expect(c.calculate(1, 2)).to.equal(3);
+  });
+
+});

docs/development/js/js-unit-test.md

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+# JS Unit Testing
+
+ILIAS is using [Mocha](https://mochajs.org/) as test framework for Javascript unit tests. The `esm` extension allows to use ES6 modules seamlessly. [Chai](https://www.chaijs.com/) is being used as assertion library.
+
+## Install
+
+```
+> npm i --save-dev mocha
+> npm i --save-dev esm
+> npm i --save-dev chai
+```
+
+## package.json changes
+
+```
+{
+  ...
+  "scripts": {
+    "test": "mocha --require esm"
+  },
+  ...
+}
+```
+
+## Run tests
+
+```
+> npm test
+```
+
+## Example
+
+Your tests should be located in a subdirectory `test`.
+
+See [js-unit-test-example/test/component.test.js](./js-unit-test-example/test/component.test.js).