Let’s do some boundary testing and implement it using the Parameterized Tests feature from JUnit 5 that we saw in the video.

1. Create a ChocolateBagsTest class, under the tudelft.chocolate package.
2. Replace its code by the one with all the boundary tests:

   package tudelft.chocolate;
   
   import org.junit.jupiter.api.Assertions;
   import org.junit.jupiter.params.ParameterizedTest;
   import org.junit.jupiter.params.provider.CsvSource;
   
   public class ChocolateBagsTest {
       @ParameterizedTest(name = "small={0}, big={1}, total={2}, result={3}")
       @CsvSource({ "1,1,5,0", "1,1,6,1", "1,1,7,-1", "1,1,8,-1" })
       public void totalIsTooBig(int small, int big, int total, int expectedResult) {
           ChocolateBags bags = new ChocolateBags();
           int result = bags.calculate(small, big, total);
           Assertions.assertEquals(expectedResult, result);
       }
   
       @ParameterizedTest(name = "small={0}, big={1}, total={2}, result={3}")
       @CsvSource({ "4,0,10,-1", "4,1,10,-1", "5,2,10,0", "5,3,10,0" })
       public void onlyBigBars(int small, int big, int total, int expectedResult) {
           int result = new ChocolateBags().calculate(small, big, total);
           Assertions.assertEquals(expectedResult, result);
       }

   1.  @ParameterizedTest(name = "small={0}, big={1}, total={2}, result={3}")
          @CsvSource({
              "0,3,17,-1", "1,3,17,-1", "2,3,17,2", "3,3,17,2",
              "0,3,12,-1", "1,3,12,-1", "2,3,12,2", "3,3,12,2"})
          public void bigAndSmallBars(int small, int big, int total, int expectedResult) {
              int result = new ChocolateBags().calculate(small, big, total);
              Assertions.assertEquals(expectedResult, result);
          }
      
          @ParameterizedTest(name = "small={0}, big={1}, total={2}, result={3}")
          @CsvSource({ "4,2,3,3", "3,2,3,3", "2,2,3,-1", "1,2,3,-1" })
          public void onlySmallBars(int small, int big, int total, int expectedResult) {
              int result = new ChocolateBags().calculate(small, big, total);
              Assertions.assertEquals(expectedResult, result);
          }
      }

   2. Stop for a second and read all the tests. Make sure you understand how each part of the code works.
   3. Notice that in our code, different from the video, we have a name in the Parameterized Tests. With this parameter, we tell JUnit what name to display for each execution . In this case, we are telling JUnit that the display name should be “small={0}, big={1}, total={2}, result={3}” for each test it executes. The numbers in between brackets will be replaced by the parameters in the CsvSource.
   4. You can better see it when you run the tests:
      
   5. If you want to explore a bit more: 1) add some other inputs to the methods and see them executing (for now, you should not mind that some of them might look repetitive), 2) change the display name.