DirectorySuite.java

/*
Copyright 2011, Lightbox Technologies, Inc

Licensed 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 com.lightboxtechnologies.test;

import java.io.File;
import java.lang.reflect.Method;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Deque;
import java.util.List;

import org.junit.Test;
import org.junit.runners.Suite;
import org.junit.runners.model.InitializationError;

/**
 * A {@link Suite} which runs all tests in a directory tree.
 *
 * @author Joel Uckelman
 */
public abstract class DirectorySuite extends Suite {
  public DirectorySuite(Class<?> setupClass, String root)
                                                   throws InitializationError {
    super(setupClass, DirectorySuite.findTests(root));
  }

  protected static Class<?> loadClassByPath(String cpath) {
    // turn directory slashes into class hierarchy dots
    String cname = cpath.replace('/', '.');

    Class<?> c = null;
    try {
      return Class.forName(cname);
    }
    catch (ClassNotFoundException e) {
      throw new RuntimeException(e);
    }
  }

  protected static boolean hasTests(Class<?> c) {
    for (Method m : c.getMethods()) {
      if (m.getAnnotation(Test.class) != null) {
        return true;
      }
    }
    return false;
  }

  public static Class<?>[] findTests(String path) {
    final File root = new File(path);
    if (!root.isDirectory()) {
      throw new RuntimeException(root.getPath() + " is not a directory!");
    }

    final List<Class<?>> tests = new ArrayList<Class<?>>();

    final Deque<File> stack = new ArrayDeque<File>();
    stack.push(root);

    File dir;
    String cpath;

    while (!stack.isEmpty()) {
      dir = stack.pop();

      for (File f : dir.listFiles()) {
        if (f.isDirectory()) {
          stack.push(f);
        }
        else {
          cpath = f.getPath();
          if (cpath.endsWith("Test.java")) {
            // strip off test root and ".java"
            cpath = cpath.substring(path.length()+1, cpath.length()-5);

            // take only classes which have Test-annotated methods
            final Class<?> c = loadClassByPath(cpath);
            if (hasTests(c)) {
              tests.add(c);
            }
          }
        }
      }
    }

    return tests.toArray(new Class<?>[tests.size()]);
  }
}