package dk.itu.oop.lecture6;

import java.util.List;
import java.util.ArrayList;
import java.util.Iterator;
import java.lang.reflect.*;

public class UnitTester
{	/** testClass is the class that contains the testcases
	*/
	private Class testClass;
	/** testMethods is an vector of the methods that contain
	* consists the tests to be executed
	*/
	private List testMethods;
	/** test object is an instance of testClass.
	*/
	private Object testObject;


	/** Set the class to be testet. The className must be a name in classpath.
	*/
	private void setClass(String className)
		throws ClassNotFoundException, InstantiationException,
					IllegalAccessException {
		testClass = Class.forName(className);
		testObject = testClass.newInstance();
	}

	/**get the methods in testClass that takes no arguments, and with
	* a methodName that starts with "test".
	*/
	private void getMethods(){
		testMethods = new ArrayList();
		try{
			Method[] all = testClass.getDeclaredMethods();
			for (int i = 0; i<all.length; i++){
				if ( all[i].getName().startsWith("test") ){
					testMethods.add(all[i]);
				}
			}
		}catch(SecurityException whatWasThat){
		}
	}

	/** perform all the testMethods, and report the result
	*/
	private String performTests(){
		String result = "Test of " + testClass.getName() + "\n";
		Iterator itr = testMethods.iterator();
		while ( itr.hasNext() ){
			Method m = (Method)itr.next();
			try{
				m.invoke(testObject,new Object[0]);
				result += m.getName() + " OK\n";
			}catch(IllegalAccessException notPossible){}
			 catch(IllegalArgumentException notPossible){}
      		 catch(InvocationTargetException uups){
				Throwable target = uups.getTargetException();
				if ( target instanceof TestClass.CheckFailure)
					result += m.getName() +" Check failed: "
						+ ((TestClass.CheckFailure)target).msg + "\n";
				else
					result += m.getName() + " Exception: " + target.toString() + "\n";
			}
		}
		return result;
	}

	public static String testTheClass(String name){
		try{
			UnitTester ut = new UnitTester();
			ut.setClass(name);
			ut.getMethods();
			return ut.performTests();
		}catch(Exception uups){
			return "Could not find class " + name + "\n" + uups;
		}
	}

}