assert 를 등록 시켜보았음 여기서 assert 는 석진이가 말한 구아바의 기능을 간단하게 구현 한 것에 지나지 않음

Assert.java

package com.springapp.mvc;

public class Assert {
    public static void isNotNull(Object expected,String message) {
        if(null == expected){
            throw new AssertException(message);
        }
    }

    public static void isTrue(boolean expr, String message) {
        if(false == expr){
            throw new AssertException(message);
        }
    }
}

AssertException.java

package com.springapp.mvc;

public class AssertException extends RuntimeException {

    public AssertException(String message) {
        super(message);
    }
}

GuavaTest1.java

package com.springapp.mvc;

import static com.google.common.base.Preconditions.*;
public class GuavaTest1 {


    public void testForNonNullArgument(final String parameter){
        Assert.isNotNull(parameter,"null값은 허용되지 않습니다.");
    }

    public void testDivisorNotZero(final int divisor){
        Assert.isTrue(divisor != 0,"0으로 나눌 수 없습니다.");
    }

    public void testArrayElement(final String[] strArray, final int indexNumber){
        Assert.isTrue( 0 <= indexNumber && strArray.length > indexNumber ,"지정된 Array 요소 위치가 벗어났습니다.");
    }

    public void testArrayPosition(final String[] strArray, final int indexNumber){
        Assert.isTrue( 0 <= indexNumber && strArray.length > indexNumber ,"지정된 Array 요소 위치가 벗어났습니다.");
    }

    public void testState(){
        Assert.isTrue(false,"반드시 true ");
    }


}

TestMain.java

package com.springapp.mvc;

public class TestMain {

    public static void main(String[] args) {

        TestRunner testRunner =new TestRunner(GuavaTest1.class);

        testRunner.test("preconditions.checkNotNull", "testArrayElement", new String[]{"Dustin", "java"}, 3);
        testRunner.test("precondition.checkArgument", "testDivisorNotZero", 0);
        testRunner.test("Preconditions.checkElementIndex", "testForNonNullArgument", null);
        testRunner.test("Preconditions.checkPositionIndex", "testArrayPosition", new String[]{"Dustin", "java"}, 3);
        testRunner.test("Preconditions.checkState", "testState");
    }
}

TestMethodInvoker.java

package com.springapp.mvc;

import java.lang.reflect.InvocationTargetException;

public interface TestMethodInvoker {

    void invoker(Object testInstance, String testName, Object[] parameters) throws InvocationTargetException, IllegalAccessException;
}

TestRunner.java

package com.springapp.mvc;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import static java.lang.System.err;

public class TestRunner {
    private final Class<?> testClass;

    public TestRunner(Class<?> testClass) {
        this.testClass = testClass ;
    }

    public void test(String message, String testName,Object... parameters) {
        printHeader(message);
        try{
            TestMethodInvoker testcase = new TestMethodInvoker() {
                @Override
                public void invoker(Object testInstance, String testName, Object[] parmeters) throws InvocationTargetException, IllegalAccessException {
                    for (Method each : testClass.getMethods()) {

                        if (
                                isTestMehtod(each)) {
                            //each.
                            if (each.getName().equals(testName)) {
                                if (null == parmeters) {
                                    each.invoke(testInstance);
                                } else {
                                    each.invoke(testInstance, parmeters);
                                }
                            }

                        }
                    }
                }

            };
            testcase.invoker(testClass.newInstance(), testName, parameters);
        }catch(Exception e){
            e.printStackTrace();
        }
    }

    private  boolean isTestMehtod(Method each) {
        return each.getName().startsWith("test")
                || each.getReturnType().equals("void");
    }

    private  void printHeader(final String newHeaderText){
        line();
        err.println(newHeaderText);
        line();
    }

    private static void line() {
        err.println("==========================================");
    }
}