sedsawyum / tdd-project

Learing Test-Driven development in Python, JavaScript and Go

Test-Driven Development

TDD is a technique for designing and structuring code that encourages simplicity and increases one's confidence in code, even as its size increases.

	->> That simplicity - the art of maximizing the amount of work not done, is essential
	->> That obviousness and clarity are more virtuous than cleverness
	->> That writing uncluttered code is a key component of being successful

Red-Green-Refactor: The building block of TDD

Red:
	Write a failing test (including possible compilations failures). Run the test suite to verify the failing test.
Green:
	Write just enough production code to make the test green. Run the test suite to verify this.
Refactor:
	Remove any code smells. These mau be due to duplication, hardcoded values, or improper use of language 	idioms (e.g., using verbose loop instead of a built-in iterator). If any test breaks during refactoring, prioritize getting them back to green before exiting the phase. 

Failing: Red test

	//JavaScript
	const assert = require("assert")                                                                   
	
	let fiver = new Dollar(5)                                  
	let tenner = fiver.times(2)                                  
	assert.strictEqual(tenner.amount, 10)

			
	//Python		
	import unittest            
             
	class TestMoney(unittest.TestCase):       
		def testMultiplication(self):
			fiver = Dollar(5)
			tenner = fiver.times(2)
			self.assertEqual(10, tenner.amount)										
											
											
											
	//GO
	package main
	
	import ("testing")
	
	func TestMultiplication(t *testing.T) {
		fiver := Dollar{
			amount: 5
		}
		
		tenner := fiver.Times(2)
		if tenner.amount != 10 {
			t.Errorf("Expected 10, got: [%d]", tenner.amount)
		}
	}

Going Green: Green test

	// JavaScript
	...

	class Dollar {                                              
		constructor(amount) {
			this.amount = amount
		}
		
		times(multiplier) {
			return new Dollar(10)
		}
	}
	
	...
	
	
	//Python
	...
	
	class Dollar:
		def __init__(self, amount):
			self.amount = amount
			
		def times(self, multiplier):
			return Dollar(10)
			
	...
			
	//GO
	...
	type Dollar struct {
		amount int
	}
	
	func (d dollar) Times(multiplier int) Dollar {
		return Dollar{10}
	}
	...

Cleaning up: Refactor

	//JavaScript
	...
	times(multiplier) {
		return new Dollar(this.amount * multiplier)
	...
	
	
	//Python
	...
	def times(multiplier) {
		return Dollar(self.amount * multiplier)
	}
	...

	
	//Go 
	...
	func (d dollar) Times(multiplier int) Dollar {
		return Dollar{d.amount * multiplier}
	}
	...

This repo will contain all the resources and code examples I use to learn Test-Driven Development

This repo is based on following resources:

• Learing Test-Driven Development by Saleem Siddiqui (O'Reilly)

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