work in progress

PhoneBook.java

     String phoneNumber= "";
     Map<String,String> phoneBook = new TreeMap<>();    
     public void addEntry(String name,String phoneNumber){
-        phoneBook.put(name, phoneNumber);
+        phoneBook.put(name, phoneNumber); //add a new number
     }    
     
     public void removeEntry(String name){
-        phoneBook.remove(name);
+        phoneBook.remove(name);//delete a number
     }
     
     public int size(){
     return phoneBook.size(); //return size of the phonebook
     }
+    
+    public String lookUp(String name){
+    return phoneBook.get(name);
+    } 
 }

PhoneBookTest.java

 import org.junit.Assert;
 import org.junit.Test;
+import java.util.Map;
+import java.util.TreeMap;
 
 /**
  * The test class PhoneBookTest.
     Assert.assertEquals(0, phoneBook.size());
     }
     
-    public String lookUp(){
-    return null;
-    } 
+  
     
+    @Test
+    public void lookUp(){
+    PhoneBook phoneBook = new PhoneBook();
+    String name = "Zebra";
+    String expected = "111-222-333";
+    phoneBook.addEntry(name,expected);
+    //when
+    String actual = phoneBook.lookUp(name);
+    //then
+    Assert.assertEquals(expected,actual);
+    }
     
+    @Test
+    public void reverseLoopUp(){
+    PhoneBook phoneBook = new PhoneBook();
+    String phoneNumber = "111-222-333";
+    String expected = "Zebra";
+    //when
+    // String actual = phoneBook.reverseLookUp(phoneNumber);
+    //then
+    // Assert.assertEquals(expected,actual);
+    }
+    
+    @Test
+    public void display(){
+    }
 }