Issue #458: Groovy should throw exception if more then one World registred

groovy/pom.xml

@@ -52,6 +52,11 @@
             <artifactId>cobertura</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-all</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>

groovy/src/main/java/cucumber/runtime/groovy/GroovyBackend.java

@@ -37,7 +37,7 @@ public class GroovyBackend implements Backend {
     private final ClasspathResourceLoader classpathResourceLoader;
 
     private Closure worldClosure;
-    private Object groovyWorld;
+    private Object world;
     private Glue glue;
 
     private static GroovyShell createShell() {
@@ -97,6 +97,7 @@ public void setUnreportedStepExecutor(UnreportedStepExecutor executor) {
 
     @Override
     public void buildWorld() {
+        world = worldClosure == null ? new Object() : worldClosure.call();
     }
 
     private Script parse(Resource resource) {
@@ -113,7 +114,7 @@ private boolean isScript(Script script) {
 
     @Override
     public void disposeWorld() {
-        this.groovyWorld = null;
+        this.world = null;
     }
 
     @Override
@@ -126,6 +127,7 @@ public void addStepDefinition(Pattern regexp, int timeoutMillis, Closure body) {
     }
 
     public void registerWorld(Closure closure) {
+        if (worldClosure != null) throw new CucumberException("World is already set");
         worldClosure = closure;
     }
 
@@ -138,21 +140,14 @@ public void addAfterHook(TagExpression tagExpression, int timeoutMillis, Closure
     }
 
     public void invoke(Closure body, Object[] args) throws Throwable {
-        body.setDelegate(getGroovyWorld());
+        body.setDelegate(world);
         try {
             body.call(args);
         } catch (InvokerInvocationException e) {
             throw e.getCause();
         }
     }
 
-    private Object getGroovyWorld() {
-        if (groovyWorld == null) {
-            groovyWorld = worldClosure == null ? new Object() : worldClosure.call();
-        }
-        return groovyWorld;
-    }
-
     private static StackTraceElement currentLocation() {
         Throwable t = new Throwable();
         StackTraceElement[] stackTraceElements = t.getStackTrace();

groovy/src/test/java/cucumber/runtime/groovy/GroovyBackendTest.java

@@ -0,0 +1,47 @@
+package cucumber.runtime.groovy;
+
+import cucumber.runtime.CucumberException;
+import cucumber.runtime.io.ResourceLoader;
+import groovy.lang.Closure;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+
+import static org.mockito.Mockito.verify;
+
+
+@RunWith(MockitoJUnitRunner.class)
+public class GroovyBackendTest {
+    @Mock
+    ResourceLoader resourceLoader;
+    @Mock
+    Closure closure;
+
+    GroovyBackend backend;
+
+    @Before
+    public void setUp() throws Exception {
+        backend = new GroovyBackend(resourceLoader);
+    }
+
+    @Test
+    public void builds_world_by_calling_closure() {
+        backend.registerWorld(closure);
+        backend.buildWorld();
+
+        verify(closure).call();
+    }
+
+    @Test
+    public void builds_default_wold_if_wold_closer_does_not_set() {
+        backend.buildWorld();
+    }
+
+    @Test(expected = CucumberException.class)
+    public void raises_exception_for_two_wolds() {
+        backend.registerWorld(closure);
+        backend.registerWorld(closure);
+    }
+}