<NaN> returned for my Junit test case

[Stephen Shaw]

Here is the complete code for my class and my test class. I've highlighted the problem areas and described the problem below.

public class WholeLifePolicy
{
    // instance variables
    private String policyNum;
    private double faceValue;
    private int policyYrs;
    
    // constants
    /**
     * surrender rate.
     */    
    public static final double SURRENDER_RATE = .65;

    /**
     * ADMINFEE.
     */    
    public static final double ADMINFEE = .005;
    
    // constructors and methods
    
    /**
     * Constructor for objects of class WholeLifePolicy.
     * This is the default constructor.
     * 
     */
    public WholeLifePolicy()
    {
        this.policyNum = "WLP9999999";
        this.faceValue = 0.0;
        this.policyYrs = 0;
    }    
    
    /**
     * Constructor for objects of class WholeLifePolicy.
     * A policy number will be auto-generated.
     * 
     * @param inPolicyNum  Number of the policy
     * @param inFaceValue  Face Value of policy. 
     * @param inPolicyYrs  Length of policy in years. 
     * 
     */
    public WholeLifePolicy(String inPolicyNum, double inFaceValue,
       int inPolicyYrs)
    {
        inPolicyNum = policyNum;
        inFaceValue = faceValue;
        inPolicyYrs = policyYrs;
    }
      
    /**
     * Constructor for objects of class WholeLifePolicy.
     * This constructor creates an exact copy of a 
     * WholeLifePolicy object.
     * 
     * @param inPolicyObject   WholeLifePolicy object.
     * 
     */
    public WholeLifePolicy(WholeLifePolicy inPolicyObject)
    {
        this.policyNum = inPolicyObject.getPolicyNum();
        this.faceValue = inPolicyObject.getFaceValue();
        this.policyYrs = inPolicyObject.getPolicyYrs();
    }
      
    /**
     * Set the Policy Face Value.
     * 
     * @param inFaceValue  Face Value of policy. 
     *  
     */
    public void setFaceValue(double inFaceValue)
    {
        this.faceValue = inFaceValue;
    }
    
    /**
     * Get the Policy Face Value.
     * 
     * @return double  Face Value of policy.
     *  
     */
    public double getFaceValue()
    {
        return this.faceValue;
    }
    
    /**
     * Set the Policy Years.
     * 
     * @param inPolicyYrs  Length of policy in years.
     *  
     */
    public void setPolicyYrs(int inPolicyYrs)
    {
        this.policyYrs = inPolicyYrs;
    }
    
    /**
     * Get the Policy Years.
     * 
     * @return int  Length of policy in years.
     *  
     */
    public int getPolicyYrs()
    {   
        return this.policyYrs;
    }

    /**
     * Set the Policy Number. Use to override the default
     * policy number or for copy object processing.
     * 
     * @param inPolicyNum  Policy Number.
     *  
     */
    public void setPolicyNum(String inPolicyNum)
    {
        this.policyNum = inPolicyNum;
    }
    
    /**
     * Get the Policy Number.
     * 
     * @return String  Policy Number.
     *  
     */
    public String getPolicyNum()
    {
        return this.policyNum;
    }
    
    /**
     * Calculate surrender value.
     * 
     * @param inYrsHeld  Length in years policy held to date. 
     * @param inBorAmt   Amount borrowed against policy if any.
     * 
     * @return double  Policy surrender value.
     * 
     */
    [color=red]public double surrenderVal(double inYrsHeld, double inBorAmt)
    {
        // Termination value is the surrender rate percentage of the face
        // value as a proportion of the years held to policy years less any
        // amount borrowed on the policy less a ADMINFEE on the
        // face value.
       
       double surrenderValue = ((SURRENDER_RATE * this.faceValue) *
            (inYrsHeld / this.policyYrs) -
            inBorAmt - (this.faceValue * ADMINFEE));
        
        return surrenderValue;
    }[/color]
    
    /**
     * Return a string representation of the WholeLifePolicy.
     * 
     * @return String  output string.
     *  
     *  <pre>
     *  Produce output in the following format:
     *  
     *  Policy Information:
     *  Policy #: WLP1000000
     *  Policy Years: 20
     *  Face Value: 50000.0
     *  
     *  </pre>
     */
    public String toString()
    {
        String output = "Policy Information:\n";
        output = output + "Policy #: " + this.getPolicyNum() + "\n";
        output = output + "Policy Years: " + this.getPolicyYrs() + "\n";
        output = output + "Face Value: " + this.getFaceValue() + "\n";
        
        return output;
    }
        
}

Start of test class:

  
public class WholeLifePolicyTest extends junit.framework.TestCase
{
    
    /**
     * Default constructor for test class WholeLifePolicyTest.
     */
    public WholeLifePolicyTest()
    {
        // not used
    }

    /**
     * Sets up the test fixture.
     *
     * Called before every test case method.
     */
    protected void setUp()
    {
        // not used
    }

    /**
     * Tears down the test fixture.
     *
     * Called after every test case method.
     */
    protected void tearDown()
    {
        // not used
    }

    /**
     * Test empty (implicit) constructor #1.
     */
    public void testConstructor1()
    {
        WholeLifePolicy policy = new WholeLifePolicy();
        // verify an object reference was created
        assertNotNull(policy);
        // verify policy number is not null
        assertEquals("WLP9999999", policy.getPolicyNum());
        // verify face value set to default values
        assertEquals(0.0, policy.getFaceValue(), .001);
        // verify policy years set to default values          
        assertEquals(0, policy.getPolicyYrs());
    }    
    
    /**
     * Test explicit constructor #2 (number, face value, years).
     */
    public void testConstructor2()
    {
        // we test passing in values greater than zero only
        String num = "WLP1234567";
        double value = 50000.0;
        int years = 20;
        WholeLifePolicy policy = new WholeLifePolicy(num, value, years);
        // verify an object reference was created
        assertNotNull(policy);
        // verify policy number is not null
        policy.setPolicyNum(num);
        assertEquals(num, policy.getPolicyNum());
        // verify face value set to default values
        policy.setFaceValue(value);
        assertEquals(value, policy.getFaceValue(), .001);
        // verify policy years set to default values
        policy.setPolicyYrs(years);
        assertEquals(years, policy.getPolicyYrs());
    }
    
    /**
     * Test explicit constructor #3 (duplicate object).
     */
    public void testConstructor3()
    {
        // we test passing in values greater than zero only
        String num = "WLP1234567";
        double value = 50000.0;
        int years = 20;
        WholeLifePolicy policy1 = new WholeLifePolicy(num, value, years);
        
        WholeLifePolicy policy2 = new WholeLifePolicy(policy1);
        // verify an object reference was created
        assertNotNull(policy2);
        // verify policy number is not null
        policy2.setPolicyNum(num);
        assertEquals(num, policy2.getPolicyNum());
        // verify face value set to default values
        policy2.setFaceValue(value);
        assertEquals(value, policy2.getFaceValue(), .001);
        // verify policy years set to default values    
        policy2.setPolicyYrs(years);
        assertEquals(years, policy2.getPolicyYrs());
    }
    
    /**
     * Test the setGetFaceValue method.
     */
    public void testSetGetFaceValue()
    {
        // test passing in values greater than zero only
        double value = 75000.0;
        WholeLifePolicy policy = new WholeLifePolicy();
        policy.setFaceValue(value);
        assertEquals(value, policy.getFaceValue(), .0001);
        
    }
    
    /**
     * Test the setGetPolicyYrs method.
     */
    public void testSetGetPolicyYrs()
    {
        // test passing in values greater than zero only
        int value2 = 8888;
        WholeLifePolicy policy = new WholeLifePolicy();
        policy.setPolicyYrs(value2);
        assertEquals(value2, policy.getPolicyYrs());
    }
    
     /**
     * Test the SetGetPolicyNum method.
     */
    public void testSetGetPolicyNum()
    {
        // test passing in values greater than zero only
        String value3 = "WLP8888888";
        WholeLifePolicy policy = new WholeLifePolicy();
        policy.setPolicyNum(value3);
        assertEquals(value3, policy.getPolicyNum());
    }
    
    /**
     * Test the surrenderVal method.
     */
    [color=red]public void testSurrenderVal()
    {
        // we test passing in values greater than zero only
        String num = "WLP1234567";
        double value = 50000.0;
        int years = 20;
        double yearsHeld = 15.5;
        double amtBorrowed = 10000.00;
        WholeLifePolicy policy = new WholeLifePolicy(num, value, years);
        double surVal = policy.surrenderVal(yearsHeld, amtBorrowed);

        assertEquals(14937.5, surVal, .0001);
        
        amtBorrowed = 0;
        assertEquals(24937.5, surVal, .0001);
    }[/color]
    
    /**
     * Test the toString method.
     */
    public void testToString()
    {
       String num = "WLP1234567";
       double value = 50000.0;
       int years = 20;
       WholeLifePolicy policy = new WholeLifePolicy(num, value, years);
        
       String text = policy.toString();
       assertTrue(text.contains("Policy Information:"));
        
       assertTrue(text.contains("Policy #:"));
       assertTrue(text.contains(num));
        
       assertTrue(text.contains("Policy Years:"));
       assertEquals(20, years);

       assertTrue(text.contains("Face Value:"));
       assertEquals(50000.0, value);
    }
}  

I'm working on a lab for school but blueJ is telling me that my surrenderValue is returning "NaN" (which I know is Not a Number). I believe the issue is with the objects I am trying to use in the calculation in my WholeLifePolicy class's surrenderVal method. Any help asap would be greatly appreciated.

[Ernest Friedman-Hill]

In this constructor:

    public WholeLifePolicy(String inPolicyNum, double inFaceValue,
       int inPolicyYrs)
    {
        inPolicyNum = policyNum;
        inFaceValue = faceValue;
        inPolicyYrs = policyYrs;
    }

What you want to do is put the values of the parameters into the member variables. Is that what those three assignments are doing? Or are they maybe doing exactly the opposite?

Or to put it another way, dividing by 0 gives a NaN. If policyYrs were to remain zero after this constructor, then the value you're testing would be NaN. Are you sure policyYrs is not zero?

[Stephen Shaw]

Thank you!

You were right, I had them reversed. I would have never noticed if it wasn't for you, thanks. I'll be keeping this place bookmarked from now on. I can see how much you guys will help my learning.

[Campbell Ritchie]

Welcome to the Ranch

More precisely, you get NaN if you divide 0 by 0, but it only works in floating-point arithmetic. In floating point, if you divide anything else by 0 you get (±)∞, and in integer arithmetic you get an Exception if you divide by 0.