Loyalty.java

package edu.gmu.mut;

public class Loyalty {

	
	/**
	 * Given a a number representing the total dollar amount
	 * of purchases, this returns some discount
	 * */

	public Double getDiscount(Double totalPurchases) {
		Double retVal = 0.0;
		
		//between 100-1000
		if(totalPurchases >= 100 && totalPurchases < 1000){
			retVal = 0.10;
		}
	
		//between 1000-10000
		else if (totalPurchases >= 1000 && totalPurchases < 10000){
			retVal = 0.15;
		}
		
		//GT 10000
		else if (totalPurchases >= 10000 ){
			retVal = 0.20;
		}
		
		//GT 0
		else if  (totalPurchases > 0 ){
			retVal = 0.05;
		}
		
	    return retVal;	
	}
	
	
	
	
	
	public Double getDiscountMutant_1(Double totalPurchases) {
		Double retVal = 0.0;
		
		// between 100-1000
		// changed >= to >,<,==, what happens with 100?
		// Obviously, it is not logical to compare exact equality
		// AND any other value, as the test will either pass/fail on the first
		// expression ( totalPurchases < 1000 is NOT reachable)
		if(totalPurchases == 100 && totalPurchases < 1000){
			retVal = 0.10;
		}
	
		//between 1000-10000
		else if (totalPurchases >= 1000 && totalPurchases < 10000){
			retVal = 0.15;
		}
		
		//GT 10000
		else if (totalPurchases >= 10000 ){
			retVal = 0.20;
		}
		
		//GT 0
		else if  (totalPurchases > 0 ){
			retVal = 0.05;
		}
		
	    return retVal;	
	}
	

}

MutantLoyaltyTest.java

package edu.gmu.mut;

import java.util.logging.Logger;

import junit.framework.AssertionFailedError;

import org.junit.Test;
import static org.junit.Assert.*;

public class MutantLoyaltyTest {

	Logger logger = Logger.getLogger(this.getClass().getCanonicalName());
	
	
// what "data" be determined is missing?
	/**
	 * 
	 * Given only an input of 100.00, this test is not sensitive to  
	 * the structural change. We need to make sure we provide data
	 * elements greater than 100.00 and less than 1000.00. But, how
	 * can we compute this?
	 * 
	 * */
	@Test
	public void loyaltyTestShouldBeSensitiveToChanges(){
		Double totalPurchases = 100.00;
		Loyalty loyalty = new Loyalty();
		Double actualDiscount = loyalty.getDiscountMutant_1( totalPurchases );
		logger.info( actualDiscount.toString() );
		assertEquals( new Double(.10), actualDiscount );
	}
	
	
	
	
	
	@Test
	public void loyaltyShouldReturn10PercentForSomeCustomers(){
		Double totalPurchases = 100.00;
		Loyalty loyalty = new Loyalty();
		Double actualDiscount = loyalty.getDiscount( totalPurchases );
		logger.info( actualDiscount.toString() );
		assertEquals( new Double(.10), actualDiscount );
	}
	
		
}