Java Tutorial/JUnit/assert

assertEquals([String message],expected,actual)

import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testOrder2() {
    int[] arr = new int[3];
    arr[0] = 8;
    arr[1] = 9;
    arr[2] = 7;
    assertEquals(9, Largest.largest(arr));
  }

}
class Largest {
  /**
   * Return the largest element in a list.
   * 
   * @param list
   *            A list of integers
   * @return The largest number in the given list
   */
  public static int largest(int[] list) {
    int index, max = Integer.MAX_VALUE;
    for (index = 0; index < list.length - 1; index++) {
      if (list[index] > max) {
        max = list[index];
      }
    }
    return max;
  }
}

assertEquals([String message],expected,actual,tolerance)

check that the actual result is equal to 3.33, 
but only look at the first two decimal places:
import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testEmpty() {
      assertEquals("Should be 3 1/3", 3.33, 10.0/3.0, 0.01);
  }
}

assertFalse([String message], boolean condition)

import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testEmpty() {
    assertFalse("should be same", true);
  }
}

assertNotSame([String message], expected, actual)

import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testEmpty() {
    assertNotSame("should be same", "expected", "actual");
  }

}

assertNull([String message], java.lang.Object object)

assertNotNull([String message], java.lang.Object object)
Asserts that the given object is null (or not null), failing otherwise. The message is optional.
import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testEmpty() {
      assertNull("it should be null", null);
  }
}

assertSame([String message], expected, actual)

import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testEmpty() {
    assertSame("should be same", "expected", "actual");
  }
}

assertTrue([String message], boolean condition)

import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testEmpty() {
    assertTrue("should be same", true);
  }
}

Ensure that they are equal

import junit.framework.TestCase;
public class TestLargest extends TestCase {
  public TestLargest(String name) {
    super(name);
  }
  public void testOrder() {
    assertEquals(9, Largest.largest(new int[] { 8, 9, 7 }));
  }
}
class Largest {
  /**
   * Return the largest element in a list.
   * 
   * @param list
   *            A list of integers
   * @return The largest number in the given list
   */
  public static int largest(int[] list) {
    int index, max = Integer.MAX_VALUE;
    for (index = 0; index < list.length - 1; index++) {
      if (list[index] > max) {
        max = list[index];
      }
    }
    return max;
  }
}