Added Fido

src/main/java/demo/NullPointerDereference.java

@@ -6,16 +6,17 @@ public int getNumberOfLegs(String animal) {
     String trimmedAnimal = trim(animal);
 
     int legs;
-    int arms;
 
     if ("dog".equals(trimmedAnimal)) {
       legs = 4;
-    } else if (trimmedAnimal.equals("kangaroo")) { // NullPointer issue raised
+    } else if ("kangaroo".equals(trimmedAnimal)) { // NullPointer issue raised
       legs = 2;
     } else if ("Centipede".equals(trimmedAnimal)) {
       legs = 100;
+    } else if ("Fido".equals(trimmedAnimal)){
+      legs = 3;
     } else {
-      throw new RuntimeException(String.format("Unknown Animal %s", trimmedAnimal));
+      throw new IllegalArgumentException(String.format("Unknown Animal %s", trimmedAnimal));
     }
 
     return legs;

src/test/java/demo/NullPointerDereferenceTest.java

@@ -10,10 +10,15 @@ public class NullPointerDereferenceTest {
 
   @Test
   public void shouldGetDogPaws() {
-    assertEquals(underTest.getNumberOfLegs("dog"), 4);
+    assertEquals(4, underTest.getNumberOfLegs("dog"));
   }
 
-  @Test(expected = NullPointerException.class)
+  @Test
+  public void shouldGetFidoPaws() {
+    assertEquals(3, underTest.getNumberOfLegs("Fido"));
+  }
+
+  @Test(expected = IllegalArgumentException.class)
   public void ignoredTestThatWouldCoverBug() {
     underTest.getNumberOfLegs("");
   }