import java.io.*;
import static org.junit.Assert.*;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

/**
 * The test class CalculatorTest.
 *
 * @author  (your name)
 * @version (a version number or a date)
 */
public class CalculatorTest
{
    Calculator calcTest = new Calculator();
    double delta = 0.000000000000000000001;
    
    @Test
    public void addTest(){
        assertEquals(7.5,calcTest.add(2.25,5.25),delta);
    }

    @Test
    public void addTest_NegNum(){
        assertEquals(-15,calcTest.add(-5,-10),delta);
    }

    @Test
    public void subtractTest(){
        assertEquals(-4.5,calcTest.subtract(5.5,10),delta);
    }

    @Test
    public void subtractTest_NegNums(){
        assertEquals(5,calcTest.subtract(-5,-10),delta);
    }

    @Test
    public void multiplyTest(){
        assertEquals(12,calcTest.multiply(3,4),delta);
    }

    @Test
    public void multiply_TestDec(){
        assertEquals(1.2,calcTest.multiply(.25,4.8),delta);
    }

    @Test
    public void multiplyTest_NegNums(){
        assertEquals(15,calcTest.multiply(-3,-5),delta);
    }

    @Test
    public void divideTest(){
        assertEquals(-5, calcTest.divide(15,-3),delta);
    }

    @Test
    public void divideTest_Dec() {
        assertEquals(5, calcTest.divide(.5,.1),delta);
    }

    @Test
    public void squareTest(){
        assertEquals(100,calcTest.square(10),delta);
    }

    @Test
    public void squareTest_NegNum(){
        assertEquals(100,calcTest.square(-10),delta);
    }

    @Test
    public void squareTest_Dec(){
        assertEquals(.25,calcTest.square(.5),delta);
    }

    @Test
    public void squareRootTest(){
        assertEquals(10,calcTest.squareRoot(100),delta);
    }

    @Test
    public void squareRootTest_DecResult(){
        assertEquals(Math.sqrt(27),calcTest.squareRoot(27),delta);
    }

    @Test
    public void exponentTest(){
        assertEquals(8,calcTest.exponent(2,3),delta);
    }

    @Test
    public void exponentTest_Dec(){
        assertEquals(Math.pow(.5,.8),calcTest.exponent(.5,.8),delta);
    }
    
    @Test
    public void invertTest(){
        assertEquals(.05,calcTest.invert(20),delta);
    }
    
    @Test
    public void invertTest2(){
        assertEquals(-.01,calcTest.invert(-100),delta);
    }

    @Test
    public void invertTest3(){
        assertEquals(.25,calcTest.invert(4),delta);
    }
    
    @Test
    public void changeSignTest(){
        assertEquals(-3,calcTest.changeSign(3),delta);
    }
    
    @Test
    public void changeSignTest2(){
        assertEquals(3,calcTest.changeSign(-3),delta);
    }
    
    @Test
    public void storeMemoryTest(){
        calcTest.storeMemory(5);
        assertEquals(5,calcTest.getMemory(),delta);
    }
    
    @Test
    public void clearMemoryTest(){
        calcTest.storeMemory(20);
        assertEquals(0,calcTest.clearMemory(), delta);
    }
    
    @Test
    public void getMemoryTest(){
        calcTest.storeMemory(7);
        assertEquals(7,calcTest.getMemory(),delta);
    }
}