Refactor AbstractRequireRoles.getRolesFromString

- Add UT for the new method
- Extract method
- Rename parameters and local variable

src/main/java/org/apache/maven/plugins/enforcer/AbstractRequireRoles.java

@@ -141,16 +141,21 @@ final Set<String> getRolesFromProject( MavenProject mavenProject )
     /**
      * Returns the set of required roles from the property.
      *
-     * @param toSet
+     * @param csRoles comma-separated roles to be split
      * @return
      */
-    Set<String> getRolesFromString( final String toSet )
+    Set<String> getRolesFromString( final String csRoles )
     {
-        final String[] asList = StringUtils.split( toSet, "," );
+        return splitCsvToSet( csRoles );
+    }
+
+    static Set<String> splitCsvToSet( final String csv )
+    {
+        final String [] splitValues = StringUtils.split( csv, "," );
         final Set<String> result = new HashSet<>();
-        for ( String role : asList )
+        for ( String value : splitValues )
         {
-            result.add( role.trim() );
+            result.add( value.trim() );
         }
         return result;
     }

src/test/java/org/apache/maven/plugins/enforcer/AbstractRequireRolesTest.java

@@ -0,0 +1,57 @@
+package org.apache.maven.plugins.enforcer;
+
+/*
+ * 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 java.util.Set;
+
+import org.junit.Test;
+
+public class AbstractRequireRolesTest
+{
+    private final String CSV_TO_SPLIT = "a,b,c";
+    private final String CSV_WITH_SPACES_TO_SPLIT = " a, b ,c ";
+
+    @Test
+    public void testCsvSplitSize()
+    {
+        Set<String> values = AbstractRequireRoles.splitCsvToSet( CSV_TO_SPLIT );
+
+        assert values.size() == 3;
+    }
+
+    @Test
+    public void testCsvSplitExpectedElements()
+    {
+        Set<String> values = AbstractRequireRoles.splitCsvToSet( CSV_TO_SPLIT );
+
+        assert values.contains( "a" );
+        assert values.contains( "b" );
+        assert values.contains( "c" );
+    }
+
+    @Test
+    public void testCsvSplitTrimsValues()
+    {
+        Set<String> values = AbstractRequireRoles.splitCsvToSet( CSV_WITH_SPACES_TO_SPLIT );
+
+        assert values.contains( "a" );
+        assert values.contains( "b" );
+        assert values.contains( "c" );
+    }
+}