enforced use of TestResources as junit @rule

Signed-off-by: Igor Fedorenko <ifedorenko@apache.org>

Author: ifedorenko

maven-plugin-testing-harness/src/main/java/org/apache/maven/plugin/testing/resources/TestResources.java

@@ -73,6 +73,11 @@ protected void starting( Description d )
     public File getBasedir( String project )
         throws IOException
     {
+        if ( name == null )
+        {
+            throw new IllegalStateException( getClass().getSimpleName()
+                + " must be a test class field annotated with org.junit.Rule" );
+        }
         File src = new File( projectsDir, project ).getCanonicalFile();
         Assert.assertTrue( "Test project directory does not exist: " + src.getPath(), src.isDirectory() );
         File basedir = new File( workDir, name + "_" + project ).getCanonicalFile();

maven-plugin-testing-harness/src/test/java/org/apache/maven/plugin/testing/resources/TestResourcesTest.java

@@ -0,0 +1,34 @@
+package org.apache.maven.plugin.testing.resources;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+
+import org.junit.Test;
+
+public class TestResourcesTest
+{
+    public TestResources resources = new TestResources();
+
+    @Test( expected = IllegalStateException.class )
+    public void testNoRuleAnnotation()
+        throws Exception
+    {
+        resources.getBasedir( "dummy" );
+    }
+}