K

src/main/java/com/zipcoder/payment/Paypal.java

 package com.zipcoder.payment;
 
 public class Paypal implements Payment {
-    private final long ID;
+    private long ID;
     private String payerName;
     private String email;
 
+    Paypal (){
+        ID = 212131;
+        email = "khalil@gmail.com";
+        payerName = "Khalil";
+    }
+
     public Long getID() {
-        return null;
+        return ID;
     }
 
     public String getPayerName() {
-        return null;
+        return payerName;
     }
 
     public String getShortDescription() {
-        return null;
+        return "Paypal" + payerName +" "+ email;
     }
-    Paypal (){
-        ID = 212131;
-        email = "khalil@gmail.com";
-        payerName = "Khalil";
+
+    public void setID(long ID) {
+        this.ID = ID;
     }
 }

src/test/java/com/zipcoder/payment/PaypalTest.java

 
     @Test
     public void getID() {
+        Paypal pay = new Paypal();
+        //long ID we are testing
+
+        //Given
+        long ID = 1234567891;
+        //When
+        pay.setID(ID);
+        //Then
+        long actualID = pay.getID();
+        assertEquals(ID,actualID);
     }
 
     @Test