Alcoine · September 4, 2019 17:43 · Feb 8, 2014
diff --git a/mocha-guide-to-testing.js b/mocha-guide-to-testing.js
@@ -0,0 +1,107 @@
+// # Mocha Guide to Testing
+// Objective is to explain describe(), it(), and before()/etc hooks
+
+// 1. `describe()` is merely for grouping, which you can nest as deep
+// 2. `it()` is a test case
+// 3. `before()`, `beforeEach()`, `after()`, `afterEach()` are hooks to run
+// before/after first/each it() or describe().
+//
+// Which means, `before()` is run before first it()/describe()
+
+// -----------------------------------------------------------------------------
+
+// should.js is the preferred assertion library
+var should = require('should');
+
+// **Only 1 test case (in a nameless test suite)**
+it('birds should fly', function(){
+  /** here.should.be.tested
+    * However, as long as no error within a it(),
+    * it() is considered PASSED */
+})
+
+
+// **Only 1 test case, but nested 3-level deep**
+
+// describe() are:
+// - commonly known as test suites, which contains test cases
+// - merely groups, and you can have groups within groups
+describe('galaxy', function(){
+  describe('earth', function(){
+    describe('singapre', function(){
+      it('birds should fly', function(){ /** ... */ })
+    })
+  })
+})
+
+
+// **2 test cases in 1 test suite**
+
+// A common scenario.
+describe('singapre', function(){
+  it('birds should fly', function(){ /** ... */ })
+  it('horse should gallop', function(){ /** ... */ })
+})
+
+
+// **Run once before the first test case**
+describe('singapre', function(){
+  before(function(){
+    console.log('see.. this function is run ONCE only')
+  })
+  it('birds should fly', function(){ /** ... */ })
+  it('horse should gallop', function(){ /** ... */ })
+})
+
+
+// **Run once before each test case**
+describe('singapre', function(){
+  beforeEach(function(){
+    console.log('see.. this function is run EACH time')
+  })
+  it('birds should fly', function(){ /** ... */ })
+  it('horse should gallop', function(){ /** ... */ })
+})
+
+// **2 test suites in a big test suite**
+
+// A common scenario.
+describe('earth', function(){
+  describe('singapre', function(){
+    it('birds should fly', function(){ /** ... */ })
+  })
+  describe('malaysia', function(){
+    it('birds should soar', function(){ /** ... */ })
+  })
+})
+
+
+// **before() can be applied to describe() too**
+describe('earth', function(){
+  before(function(){
+    console.log('see.. this function is run ONCE only, before first describe()')
+  })
+  describe('singapre', function(){
+    it('birds should fly', function(){ /** ... */ })
+  })
+  describe('malaysia', function(){
+    it('birds should soar', function(){ /** ... */ })
+  })
+})
+
+
+// **beforeEach() can be applied to describe() too**
+describe('earth', function(){
+  beforeEach(function(){
+    console.log('see.. this function is run EACH time, before each describe()')
+  })
+  describe('singapre', function(){
+    it('birds should fly', function(){ /** ... */ })
+  })
+  describe('malaysia', function(){
+    it('birds should soar', function(){ /** ... */ })
+  })
+})
+
+
+