Testing with Spock – quick start

I heard about “Spock” the testing framework earlier this year. When I watched a online screencast at the time, I was impressed! Few things that I liked about it was the “Simplicity” and “intuitiveness” it brings to the table.
I see it as “groovy” to groovy, as to groovy to java.(i.e. life made simpler)
To be honest, when I learnt about it earlier, I was little skeptic if this was going to be adopted well and gonna be there for a while. Recently I visited their portal and I was glad to see that it was “Highly Active”. So, here I am trying to give it a try.
Complete Source code could be found at my github, https://github.com/manijshrestha/SpockExample

I have a simple project set up using gradle.
In this example I am going to try to create a “InventoryManager” that manages inventory for a online store.

Here is my Manager code:

package com.manijshrestha.spockexample

import com.manijshrestha.spockexample.exception.OutOfStockException
import com.manijshrestha.spockexample.exception.NotEnoughInventoryException

class InventoryManager{
	
    private def items =[:]
	
	def getCountOfInventory(item){
		items.get(item)
		}
	
	def gotTotalInventoryCount(){
		def sum = 0
		items.each{sum += it.value}
		return sum
	}
	
	def checkout(String item, int qty){
		def availQty = items.get(item)
		if(availQty <= 0)
			throw new OutOfStockException()
		if(qty > availQty)
			throw new NotEnoughInventoryException()
		
			items.put(item, availQty - qty)	
	}
}

And here is a simple test class used to test this code:

package com.manijshrestha.spockexample

import spock.lang.Specification
import com.manijshrestha.spockexample.InventoryManager
import com.manijshrestha.spockexample.exception.OutOfStockException
import com.manijshrestha.spockexample.exception.NotEnoughInventoryException

/**
 * Created by IntelliJ IDEA.
 * User: manijshrestha
 * Date: 10/12/11
 * Time: 11:10 PM
 * To change this template use File | Settings | File Templates.
 */
class InventoryManagerTest extends Specification{
	
	def inventoryManager = new InventoryManager()
	
	def "count of items in inventory"(){
		when:
			inventoryManager.items = ["cd": 3]
		then:
		    inventoryManager.getCountOfInventory("cd") == 3
	}
	
	def "total count of all inventories"(){
		when:
			inventoryManager.items = ["laptop": 10, "cellphone": 5, "tablet":5]
		
		then:
			inventoryManager.gotTotalInventoryCount() == 20
	}
	
	def "throw exception when trying to checkout item out of stock"(){
		when:
			inventoryManager.items = ["droidx": 0]
			inventoryManager.checkout("droidx", 1) // trying to buy droidx
		then:
			thrown(OutOfStockException)
	}
	
	def "throw exception when trying to checkout more qty than avail"(){
		when:
			inventoryManager.items = ["led tv": 2]
			inventoryManager.checkout("led tv", 3)
		then:
			thrown(NotEnoughInventoryException)
	}
	
	def "reduces correct number of items"(){
		when:
			inventoryManager.items=["dvd" : 10]
			inventoryManager.checkout("dvd", 7)
		then:
			inventoryManager.items.dvd == 3
	}

}

Few things I would like to point out here, the method names are Strings, which makes it a nice and readable test case rather than a camel cased or underscore delimited method names.
These tests I think are more readable and simple to understand. Well, I do have a very simple example here but with its power, I think writing complex test will still be simpler compared to regular jUnit tests.