Create BEANUTILS-566 tests

src/test/java/org/apache/commons/beanutils2/bugs/Jira566TestCase.java

@@ -16,20 +16,123 @@
  */
 package org.apache.commons.beanutils2.bugs;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import org.apache.commons.beanutils2.LoggerUtil;
+import org.apache.commons.logging.LogFactory;
+import org.junit.jupiter.api.Test;
+
 /**
- * Test class for {@code LoggerUtil}.
+ * Test class for {@code LoggerUtil}
  * https://issues.apache.org/jira/browse/BEANUTILS-566
  */
 public class Jira566TestCase {
 
-    public class CustomClassLoader extends ClassLoader {
+    private static CustomURLClassLoader CUSTOM_CLASSLOADER;
+
+    private static Boolean IS_CUSTOM_CLASSLOADER_INVOKED = false;
+
+    private static class CustomURLClassLoader extends URLClassLoader {
+
+        public CustomURLClassLoader(URL[] urls, ClassLoader parent) {
+            super(urls, parent);
+        }
+
+        /*
+         * Given the following default loadClass implementation steps (in order, per the JavaDoc):
+         * 1)  Invoke findLoadedClass(String) to check if the class has already been loaded.
+         * 2)  Invoke the loadClass method on the parent class loader. If the parent is null the class loader built-in to the virtual machine is used, instead.
+         * 3)  Invoke the findClass(String) method to find the class.
+         *
+         * If the name matches Jira566TestCase, then we find that class with this classloader instead via findClass.
+         * Calling newInstance().getClass().getClassLoader() on the returned class object would an instance of CustomURLClassLoader.
+         * Otherwise, if findLoadedClass or loadClass are used instead, then the original classloader is used (i.e jdk.internal.loader.ClassLoaders$AppClassLoader)
+         *
+         */
+        @Override
+        public Class<?> loadClass(String name) throws ClassNotFoundException {
+            if (name.equals("org.apache.commons.beanutils2.bugs.Jira566TestCase")) {
+                // System.out.println("match: " + name); // debug
+                return findClass(name);
+            } else {
+                // System.out.println("super: " + name); // debug
+                IS_CUSTOM_CLASSLOADER_INVOKED = true;
+                return super.loadClass(name);
+            }
+        }
+
+    }
+
+
+    public static void setup() throws Exception {
+        Path targetPath = Paths.get(Jira566TestCase.class.getResource("/").toURI()).getParent();
+        ClassLoader parent = Jira566TestCase.class.getClassLoader();
+        CUSTOM_CLASSLOADER = new CustomURLClassLoader(new URL[] {new File(targetPath.toString(), "test-classes").toURI().toURL()}, parent);
     }
 
     /*
      * Tests that context classloader is used
      */
-    // @Test
-    public void testClassLoaderUsed() throws Exception {
-        // TODO
+    @Test
+    public void testContextClassLoaderUsed() throws Exception {
+
+        setup();
+
+        /*
+         * Create an instance of this class (Jira566TestCase) so that it's classloader is CustomURLClassLoader
+         */
+        Class<?> loadedClass = CUSTOM_CLASSLOADER.loadClass("org.apache.commons.beanutils2.bugs.Jira566TestCase");
+        Class<?> instance = loadedClass.newInstance().getClass();
+
+        IS_CUSTOM_CLASSLOADER_INVOKED = false; // reset to false
+
+        /*
+         * When the logger is created, the creation will go through CustomURLClassLoader#loadClass
+         */
+        LoggerUtil.createLoggerwithContextClassLoader(instance);
+
+        assertTrue("Context ClassLoader was not invoked", IS_CUSTOM_CLASSLOADER_INVOKED);
+    }
+
+    /*
+     * Tests that original classloader is used
+     */
+    @Test
+    public void testOriginalClassLoaderUsed() throws Exception {
+
+        setup();
+
+        IS_CUSTOM_CLASSLOADER_INVOKED = false; // reset to false
+        LogFactory.getLog(Jira566TestCase.class);
+
+        assertFalse("Context ClassLoader was invoked when it should not have been", IS_CUSTOM_CLASSLOADER_INVOKED);
+    }
+
+    /*
+     * The LoggerUtil.createLoggerwithContextClassLoader method swaps out the classloaders,
+     * so this test checks to make it the original is set back.
+     */
+    @Test
+    public void testClassLoaderIsSetBackToOriginalInLoggerUtil() throws Exception {
+
+        ClassLoader original = Thread.currentThread().getContextClassLoader();
+        try {
+            Thread.currentThread().setContextClassLoader(CUSTOM_CLASSLOADER);
+            LoggerUtil.createLoggerwithContextClassLoader(Jira566TestCase.class);
+
+            assertEquals("Classloader do not match!",Thread.currentThread().getContextClassLoader(), CUSTOM_CLASSLOADER);
+        } finally {
+            // set it back to avoid any problems in the other tests
+            Thread.currentThread().setContextClassLoader(original);
+        }
+
     }
 }