When you create a test for your class, what kind of naming convention do you use for the tests? How thorough are your tests? I have lately switched from the conventional camel case test names to lower case letters with underscores. I have found this increases the readability and causes me to write better tests.

A simple utility class:

public class ArrayUtils {

  public static < T > T[] gimmeASlice(T[] anArray, Integer start, Integer end) {
    // implementation (feeling lazy today)
  }

}

I have seen some people who would write a test like this:

public class ArrayUtilsTest {

  @Test
  public void testGimmeASliceMethod() {
    // do some tests
  }
}

A more thorough and readable test would be:

public class ArrayUtilsTest {

  @Test
  public void gimmeASlice_returns_appropriate_slice() {
    // ...
  }

  @Test
  public void gimmeASlice_throws_NullPointerException_when_passed_null() {
    // ...
  }

  @Test
  public void gimmeASlice_returns_end_of_array_when_slice_is_partly_out_of_bounds() {
   // ...
  }

  @Test
  public void gimmeASlice_returns_empty_array_when_slice_is_completely_out_of_bounds() {
    // ...
  }
}

Looking at this test, you have no doubt what the method is supposed to do. And, when one fails, you will know exactly what the issue is.

Tags: agile, java, ruby, unit tests