Copying from Collections to Lang

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/lang/trunk@1154837 13f79535-47bb-0310-9956-ffa450edef68

src/test/java/org/apache/commons/lang3/compare/AbstractTestComparator.java

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+/*
+ * 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.
+ */
+package org.apache.commons.collections.comparators;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.LinkedList;
+import java.util.List;
+
+import org.apache.commons.collections.AbstractTestObject;
+
+/**
+ * Abstract test class for testing the Comparator interface.
+ * <p>
+ * Concrete subclasses declare the comparator to be tested.
+ * They also declare certain aspects of the tests.
+ *
+ * @author Stephen Colebourne
+ */
+public abstract class AbstractTestComparator<T> extends AbstractTestObject {
+
+    /**
+     * JUnit constructor.
+     * 
+     * @param testName  the test class name
+     */
+    public AbstractTestComparator(String testName) {
+        super(testName);
+    }
+
+    //-----------------------------------------------------------------------
+    
+    /**
+     * Implement this method to return a list of sorted objects.
+     * 
+     * @return sorted objects
+     */
+    public abstract List<T> getComparableObjectsOrdered();
+
+    //-----------------------------------------------------------------------
+    /**
+     * Implements the abstract superclass method to return the comparator.
+     * 
+     * @return a full iterator
+     */
+    @Override
+    public abstract Comparator<T> makeObject();
+
+    /**
+     * Overrides superclass to block tests.
+     */
+    @Override
+    public boolean supportsEmptyCollections() {
+        return false;
+    }
+
+    /**
+     * Overrides superclass to block tests.
+     */
+    @Override
+    public boolean supportsFullCollections() {
+        return false;
+    }
+
+    /**
+     * Overrides superclass to set the compatability to version 2
+     * as there were no Comparators in version 1.x.
+     */
+    @Override
+    public String getCompatibilityVersion() {
+        return "2";
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Reverse the list.
+     */
+    protected void reverseObjects(List<?> list) {
+        Collections.reverse(list);
+    }
+
+    /**
+     * Randomize the list.
+     */
+    protected void randomizeObjects(List<?> list) {
+        Collections.shuffle(list);
+    }
+
+    /**
+     * Sort the list.
+     */
+    protected void sortObjects(List<T> list, Comparator<? super T> comparator) {
+        Collections.sort(list, comparator);
+    }
+
+    //-----------------------------------------------------------------------
+    /**
+     * Test sorting an empty list
+     */
+    public void testEmptyListSort() {
+        List<T> list = new LinkedList<T>();
+        sortObjects(list, makeObject());
+
+        List<T> list2 = new LinkedList<T>();
+
+        assertTrue("Comparator cannot sort empty lists", list2.equals(list));
+    }
+
+    /**
+     * Test sorting a reversed list.
+     */
+    public void testReverseListSort() {
+        Comparator<T> comparator = makeObject();
+
+        List<T> randomList = getComparableObjectsOrdered();
+        reverseObjects(randomList);
+        sortObjects(randomList, comparator);
+
+        List<T> orderedList = getComparableObjectsOrdered();
+
+        assertTrue("Comparator did not reorder the List correctly",
+                   orderedList.equals(randomList));
+    }
+
+    /**
+     * Test sorting a random list.
+     */
+    public void testRandomListSort() {
+        Comparator<T> comparator = makeObject();
+
+        List<T> randomList = getComparableObjectsOrdered();
+        randomizeObjects(randomList);
+        sortObjects(randomList,comparator);
+
+        List<T> orderedList = getComparableObjectsOrdered();
+
+        /* debug 
+        Iterator i = randomList.iterator();
+        while (i.hasNext()) {
+            System.out.println(i.next());
+        }
+        */
+
+        assertTrue("Comparator did not reorder the List correctly",
+                   orderedList.equals(randomList));
+
+    }
+
+    /**
+     * Nearly all Comparators should be Serializable.
+     */
+    public void testComparatorIsSerializable() {
+        Comparator<T> comparator = makeObject();
+        assertTrue("This comparator should be Serializable.",
+                   comparator instanceof Serializable);
+    }
+
+    public String getCanonicalComparatorName(Object object) {
+        StringBuilder retval = new StringBuilder();
+        retval.append("data/test/");
+        String colName = object.getClass().getName();
+        colName = colName.substring(colName.lastIndexOf(".")+1,colName.length());
+        retval.append(colName);
+        retval.append(".version");
+        retval.append(getCompatibilityVersion());
+        retval.append(".obj");
+        return retval.toString();
+    }
+
+    /**
+     * Compare the current serialized form of the Comparator
+     * against the canonical version in SVN.
+     */
+    @SuppressWarnings("unchecked")
+    public void testComparatorCompatibility() throws IOException, ClassNotFoundException {
+        if (!skipSerializedCanonicalTests()) {
+            Comparator<T> comparator = null;
+    
+            // test to make sure the canonical form has been preserved
+            try {
+                comparator = (Comparator<T>) readExternalFormFromDisk(getCanonicalComparatorName(makeObject()));
+            } catch (FileNotFoundException exception) {
+    
+                boolean autoCreateSerialized = false;
+    
+                if (autoCreateSerialized) {
+                      comparator = makeObject();
+                    String fileName = getCanonicalComparatorName(comparator);
+                    writeExternalFormToDisk((Serializable) comparator, fileName);
+                    fail("Serialized form could not be found.  A serialized version "
+                            + "has now been written (and should be added to CVS): " + fileName);
+                } else {
+                    fail("The Serialized form could be located to test serialization "
+                            + "compatibility: " + exception.getMessage());
+                }
+            }
+    
+            
+            // make sure the canonical form produces the ordering we currently
+            // expect
+            List<T> randomList = getComparableObjectsOrdered();
+            reverseObjects(randomList);
+            sortObjects(randomList, comparator);
+    
+            List<T> orderedList = getComparableObjectsOrdered();
+    
+            assertTrue("Comparator did not reorder the List correctly",
+                       orderedList.equals(randomList));
+        }
+    }
+
+}