Base class for testing Velocity templates.

git-svn-id: https://samskivert.googlecode.com/svn/trunk@1970 6335cc39-0255-0410-8fd6-9bcaacd3b74c

src/java/com/samskivert/velocity/VelocityTestCase.java

@@ -0,0 +1,122 @@
+//
+// $Id$
+//
+// samskivert library - useful routines for java programs
+// Copyright (C) 2006 Michael Bayne
+// 
+// This library is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License as published
+// by the Free Software Foundation; either version 2.1 of the License, or
+// (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+package com.samskivert.velocity;
+
+import java.io.InputStream;
+import java.io.StringWriter;
+
+import junit.framework.Test;
+import junit.framework.TestCase;
+
+import org.apache.commons.io.IOUtils;
+
+import org.apache.velocity.VelocityContext;
+import org.apache.velocity.app.VelocityEngine;
+
+/**
+ * An abstract base class for easily testing Velocity templates.
+ */
+public abstract class VelocityTestCase extends TestCase
+{
+    protected VelocityTestCase (String name)
+    {
+        super(name);
+    }
+
+    protected VelocityTestCase ()
+    {
+        this(VelocityTestCase.class.getName());
+    }
+
+    @Override // from TestCase
+    protected void setUp ()
+    {
+        try {
+            _engine = VelocityUtil.createEngine();
+        } catch (Exception e) {
+            fail("Velocity initialization failed " + e);
+        }
+    }
+
+    @Override // from TestCase
+    protected void runTest ()
+    {
+        for (String template : getTemplates()) {
+            try {
+                runTest(template);
+            } catch (Exception e) {
+                fail("Failed to process " + template + ": " + e);
+            }
+        }
+    }
+
+    protected void runTest (String template)
+        throws Exception
+    {
+        // first load our golden output
+        String goldpath = getGoldenFilePath(template);
+        InputStream goldin =
+            getClass().getClassLoader().getResourceAsStream(goldpath);
+        if (goldin == null) {
+            fail("Missing golden file for " + template +
+                 " [path=" + goldpath + "].");
+        }
+        String goldtext = IOUtils.toString(goldin);
+
+        // now generate the test output
+        VelocityContext context = new VelocityContext();
+        populateContext(template, context);
+        StringWriter writer = new StringWriter();
+        _engine.mergeTemplate(template, context, writer);
+
+        // and compare the two
+        assertEquals("Template output incorrect [template=" + template +
+                     ", golden=" + goldpath + "].",
+                     goldtext, writer.toString());
+    }
+
+    /**
+     * Returns an array of template paths which will be resolved on the
+     * classpath.
+     */
+    protected abstract String[] getTemplates ();
+
+    /**
+     * Called before parsing each template to populate the context as needed
+     * for the template in question. The default implementation adds nothing to
+     * the context.
+     */
+    protected void populateContext (String template, VelocityContext context)
+    {
+    }
+
+    /**
+     * Returns the path (resolved via the classloader) of the golden file
+     * against which to compare the output of the supplied template. The
+     * default simply appends .test to the path.
+     */
+    protected String getGoldenFilePath (String template)
+    {
+        return template + ".test";
+    }
+
+    protected VelocityEngine _engine;
+}