Added a basic unit test for some of the AppStateManager functionality.

(Specifically the stuff that deals with IDs.)
Also added the ability to use groovy tests for those who like a little
testing but aren't complete masochists.

common.gradle

@@ -3,6 +3,7 @@
 //
 
 apply plugin: 'java'
+apply plugin: 'groovy'
 apply plugin: 'maven'
 
 group = 'org.jmonkeyengine'
@@ -26,8 +27,20 @@ dependencies {
     testCompile group: 'junit', name: 'junit', version: '4.12'
     testCompile group: 'org.mockito', name: 'mockito-core', version: '1.10.19'
     testCompile group: 'org.easytesting', name: 'fest-assert-core', version: '2.0M10'
+    testCompile 'org.codehaus.groovy:groovy-all:2.5.8'
 }
 
+
+// Uncomment if you want to see the status of every test that is run and
+// the test output.
+/*
+test {
+    testLogging {
+        events "passed", "skipped", "failed", "standardOut", "standardError"
+    }
+}
+*/
+
 jar {
     manifest {
         attributes 'Implementation-Title': 'jMonkeyEngine',

jme3-core/src/test/groovy/com/jme3/app/state/AppStateManagerTest.groovy

@@ -0,0 +1,98 @@
+package com.jme3.app.state;
+
+import com.jme3.app.LegacyApplication;
+
+class AppStateManagerTest {
+
+    static class AttachTest extends GroovyTestCase {
+        
+        void testDuplicateId() {
+            def state1 = new AbstractAppState("test1") {};
+            def state2 = new AbstractAppState("test1") {};
+            
+            def app = new LegacyApplication();
+            
+            app.getStateManager().attach(state1);
+            
+            shouldFail(IllegalArgumentException) {
+                app.getStateManager().attach(state2);
+            }
+        }
+        
+        void testDuplicateNullId() {
+            // Make sure that two states without an ID can
+            // still be registered. 
+            def state1 = new AbstractAppState() {};
+            def state2 = new AbstractAppState() {};
+            
+            def app = new LegacyApplication();
+            
+            app.getStateManager().attach(state1);
+            app.getStateManager().attach(state2);
+        }
+    }
+
+    static class GetStateWithIdTest extends GroovyTestCase {
+        void testIdHit() {
+            def state = new AbstractAppState("test1") {};          
+            def app = new LegacyApplication();
+            
+            app.stateManager.attach(state);
+            
+            assertNotNull app.stateManager.getState("test1", AppState.class);
+        }
+        
+        void testIdMiss() {
+            def state = new AbstractAppState("test1") {};          
+            def app = new LegacyApplication();
+            
+            app.stateManager.attach(state);
+            
+            assertNull app.stateManager.getState("test2", AppState.class);
+        }
+        
+        void testDetached() {
+            def state = new AbstractAppState("test1") {};          
+            def app = new LegacyApplication();
+            
+            app.stateManager.attach(state);
+            app.stateManager.detach(state);
+            
+            assertNull app.stateManager.getState("test2", AppState.class);
+        }
+    }
+    
+    static class StateForIdTest extends GroovyTestCase {
+        void testIdHit() {
+            def state = new AbstractAppState("test1") {};          
+            def app = new LegacyApplication();
+            
+            app.stateManager.attach(state);
+            
+            assertNotNull app.stateManager.stateForId("test1", AppState.class);
+        }
+        
+        void testIdMiss() {
+            def state = new AbstractAppState("test1") {};          
+            def app = new LegacyApplication();
+            
+            app.stateManager.attach(state);
+ 
+            shouldFail(IllegalArgumentException) {           
+                app.stateManager.stateForId("test2", AppState.class);
+            }
+        }
+        
+        void testDetached() {
+            def state = new AbstractAppState("test1") {};          
+            def app = new LegacyApplication();
+            
+            app.stateManager.attach(state);
+            app.stateManager.detach(state);
+            
+            shouldFail(IllegalArgumentException) {           
+                app.stateManager.stateForId("test2", AppState.class);
+            }
+        }
+    }
+}