diff --git a/src/groovy/org/apache/shiro/grails/MockUtils.groovy b/src/groovy/org/apache/shiro/grails/MockUtils.groovy
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+/*
+ * Copyright 2015 Yellowsnow.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ *
+ *
+ */
+package org.apache.shiro.grails
+
+import org.apache.shiro.SecurityUtils
+import org.apache.shiro.subject.Subject
+import org.apache.shiro.util.ThreadContext
+
+/**
+ * 
+ * Sometimes we need to mock an authenticated principal in our grails tests, this class serves that exact purpose.
+ *
+ */
+
+class MockUtils {
+    /**
+    * Mock an authenticated principal
+    * 
+    * @principal The shiro principal object, defaults to 'testUser'
+    */
+    static mockAuthenticatedPrincipal(principal = 'testUser'){
+        def subject = [ getPrincipal: { principal },
+                        isAuthenticated: { true }
+                      ] as Subject
+        ThreadContext.put( ThreadContext.SECURITY_MANAGER_KEY,
+                            [ getSubject: { subject } ] as SecurityManager )
+        SecurityUtils.metaClass.static.getSubject = { subject }
+    }
+}