Fixed MockBeanManager to not return null on methods returning collection

and fixed ELUtilsTest failing due to BeanManager now being required
before ApplicationImpl is created (as it needs context params which now
checks FacesConfig annotation via CDI)

impl/src/test/java/com/sun/faces/el/ELUtilsTest.java

@@ -46,12 +46,12 @@ public URL getResource(String path) {
                 "com.sun.faces.mock.MockRenderKitFactory");
 
         new FacesContextImpl(externalContext, new LifecycleImpl());
+        FacesContext.getCurrentInstance().getAttributes().put(RIConstants.CDI_BEAN_MANAGER, new MockBeanManager());
         new ApplicationImpl();
 
         applicationAssociate = (ApplicationAssociate) externalContext.getApplicationMap()
                 .get(RIConstants.FACES_PREFIX + "ApplicationAssociate");
 
-        FacesContext.getCurrentInstance().getAttributes().put(RIConstants.CDI_BEAN_MANAGER, new MockBeanManager());
     }
 
     @Test

impl/src/test/java/com/sun/faces/mock/MockBeanManager.java

@@ -16,6 +16,8 @@
 
 package com.sun.faces.mock;
 
+import static java.util.Collections.emptySet;
+
 import java.lang.annotation.Annotation;
 import java.lang.reflect.Type;
 import java.util.List;
@@ -71,12 +73,12 @@ public <T> CreationalContext<T> createCreationalContext(Contextual<T> contextual
 
     @Override
     public Set<Bean<?>> getBeans(Type beanType, Annotation... qualifiers) {
-        return null;
+        return emptySet();
     }
 
     @Override
     public Set<Bean<?>> getBeans(String name) {
-        return null;
+        return emptySet();
     }
 
     @Override
@@ -156,12 +158,12 @@ public boolean isPassivatingScope(Class<? extends Annotation> annotationType) {
 
     @Override
     public Set<Annotation> getInterceptorBindingDefinition(Class<? extends Annotation> bindingType) {
-        return null;
+        return emptySet();
     }
 
     @Override
     public Set<Annotation> getStereotypeDefinition(Class<? extends Annotation> stereotype) {
-        return null;
+        return emptySet();
     }
 
     @Override