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Mockito – First Application

Before going into the details of the Mockito Framework, let’s see an application in action. In this example, we’ve created a mock of Stock Service to get the dummy price of some stocks and unit tested a java class named Portfolio.

The process is discussed below in a step-by-step manner.

Step 1 − Create a JAVA class to represent the Stock

File: Stock.java

public class Stock {
   private String stockId;
   private String name;    
   private int quantity;
 
   public Stock(String stockId, String name, int quantity){
      this.stockId = stockId;
      this.name = name;           
      this.quantity = quantity;         
   }
 
   public String getStockId() {
      return stockId;
   }
 
   public void setStockId(String stockId) {
      this.stockId = stockId;
   }
 
   public int getQuantity() {
      return quantity;
   }
 
   public String getTicker() {
      return name;
   }
}

Step 2 − Create an interface StockService to get the price of a stock

File: StockService.java

public interface StockService {
   public double getPrice(Stock stock);
}

Step 3 − Create a class Portfolio to represent the portfolio of any client

File: Portfolio.java

import java.util.List;
 
public class Portfolio {
   private StockService stockService;
   private List<Stock> stocks;
 
   public StockService getStockService() {
      return stockService;
   }
   
   public void setStockService(StockService stockService) {
      this.stockService = stockService;
   }
 
   public List<Stock> getStocks() {
      return stocks;
   }
 
   public void setStocks(List<Stock> stocks) {
      this.stocks = stocks;
   }
 
   public double getMarketValue(){
      double marketValue = 0.0;
      
      for(Stock stock:stocks){
         marketValue += stockService.getPrice(stock) * stock.getQuantity();
      }
      return marketValue;
   }
}

Step 4 − Test the Portfolio class

Let’s test the Portfolio class, by injecting in it a mock of stock service. Mock will be created by Mockito.

File: PortfolioTester.java

package com.adglob.mock;
 
import java.util.ArrayList;
import java.util.List;
 
import static org.mockito.Mockito.*;
 
public class PortfolioTester {
       
   Portfolio portfolio;    
   StockService stockService;
          
   
   public static void main(String[] args){
      PortfolioTester tester = new PortfolioTester();
      tester.setUp();
      System.out.println(tester.testMarketValue()?"pass":"fail");
   }
   
   public void setUp(){
      //Create a portfolio object which is to be tested            
      portfolio = new Portfolio();             
  
      //Create the mock object of stock service
      stockService = mock(StockService.class);       
  
      //set the stockService to the portfolio
      portfolio.setStockService(stockService);
   }
   
   public boolean testMarketValue(){
          
      //Creates a list of stocks to be added to the portfolio
      List<Stock> stocks = new ArrayList<Stock>();
      Stock googleStock = new Stock("1","Google", 10);
      Stock microsoftStock = new Stock("2","Microsoft",100);       
 
      stocks.add(googleStock);
      stocks.add(microsoftStock);
 
      //add stocks to the portfolio
      portfolio.setStocks(stocks);
 
      //mock the behavior of stock service to return the value of various stocks
      when(stockService.getPrice(googleStock)).thenReturn(50.00);
      when(stockService.getPrice(microsoftStock)).thenReturn(1000.00);              
 
      double marketValue = portfolio.getMarketValue();             
      return marketValue == 100500.0;
   }
}

Step 5 − Verify the result

Compile the classes using the javac compiler as follows −

C:\Mockito_WORKSPACE>javac Stock.java StockService.java Portfolio.java PortfolioTester.java

Now run the PortfolioTester to see the result −

C:\Mockito_WORKSPACE>java PortfolioTester

Verify the Output

pass

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