Tests for a POJO class ProgressableItem

Question

I have tests for simple POJO class ProgressableItem (i.e. the one which has attributes total work and work done).

I use JUnit 3 (it's from Android application).

public class ProgressableItemTest extends AndroidTestCase {
 private ProgressableItem item;
 @Override
 protected void setUp() throws Exception {
 super.setUp();
 item = new ProgressableItem("item", "test item", 0, 100);
 }
 public void testNotEquals() {
 ProgressableItem itemWithDifferentName = copyOf(item);
 itemWithDifferentName.setName("Not the same " + item.getName());
 assertThat(itemWithDifferentName, not(item));
 ProgressableItem itemWithDifferentDescription = copyOf(item);
 itemWithDifferentName.setDescription("Not the same " + item.getDescription());
 assertThat(itemWithDifferentDescription, not(item));
 ProgressableItem itemWithDifferentProgress = copyOf(item);
 itemWithDifferentName.setProgress(item.getProgress() + 1);
 assertThat(itemWithDifferentProgress, not(item));
 ProgressableItem itemWithDifferentMax = copyOf(item);
 itemWithDifferentName.setMax(item.getMax() + 1);
 assertThat(itemWithDifferentMax, not(item));
 }
 private static ProgressableItem copyOf(ProgressableItem item) {
 return new ProgressableItem(item.getName(), item.getDescription(), item.getProgress(), item.getMax());
 }
}
public interface Handler<T> {
 void handle(T obj);
}

Then I modified it into:

public void testNotEquals() {
 for (Handler<ProgressableItem> progressableItemModifier : PROGRESSABLE_ITEM_MODIFIERS) {
 ProgressableItem differentItem = copyOf(item);
 progressableItemModifier.handle(differentItem);
 assertThat(differentItem, not(item));
 }
}
private static final Collection<? extends Handler<ProgressableItem>>
 PROGRESSABLE_ITEM_MODIFIERS = Arrays.asList(
 new Handler<ProgressableItem>() {
 @Override
 public void handle(ProgressableItem obj) {
 obj.setName("Not the same " + obj.getName());
 }
 },
 new Handler<ProgressableItem>() {
 @Override
 public void handle(ProgressableItem obj) {
 obj.setDescription("Not the same " + obj.getDescription());
 }
 },
 new Handler<ProgressableItem>() {
 @Override
 public void handle(ProgressableItem obj) {
 obj.setProgress(obj.getProgress() + 1);
 }
 },
 new Handler<ProgressableItem>() {
 @Override
 public void handle(ProgressableItem obj) {
 obj.setMax(obj.getMax() + 1);
 }
 }
);

But now I have many more lines of code.

Which of the two options is better? Should I separate the test method into 4 small methods? Is there no need to check each case?

• Jeroen Vannevel: Loops inside unit tests are not done. You want one test for each scenario, otherwise when one test fails, you're left to guess which one it was.

Answer 1

A couple of tips for unit testing:

• One test case per subject: so you should definitely split the cases
• Ideally no logic at all: avoid loops
• Duplication is acceptable: clarity is most important

I would write this way:

public void testNotEquals_IfNameChanged() {
 ProgressableItem itemWithDifferentName = copyOf(item);
 itemWithDifferentName.setName("Not the same " + item.getName());
 assertThat(itemWithDifferentName, not(item));
}
public void testNotEquals_IfDescriptionChanged() {
 ProgressableItem itemWithDifferentDescription = copyOf(item);
 itemWithDifferentName.setDescription("Not the same " + item.getDescription());
 assertThat(itemWithDifferentDescription, not(item));
}
public void testNotEquals_IfProgressChanged() {
 ProgressableItem itemWithDifferentProgress = copyOf(item);
 itemWithDifferentName.setProgress(item.getProgress() + 1);
 assertThat(itemWithDifferentProgress, not(item));
}
public void testNotEquals_IfMaxChanged() {
 ProgressableItem itemWithDifferentMax = copyOf(item);
 itemWithDifferentName.setMax(item.getMax() + 1);
 assertThat(itemWithDifferentMax, not(item));
}

Since you never change item, you don't really need the setUp method:

private final ProgressableItem item = new ProgressableItem("item", "test item", 0, 100);

Of course just because it's final nothing prevents you from mutating it.

To be extra safe and stay efficient, you could create an unmodifiable ProgressableItem, for example:

private final ProgressableItem item = new ProgressableItem("item", "test item", 0, 100) {
 @Override
 public void setName(String name) {
 throw new UnsupportedOperationException();
 }
 // ... + the other setters too
};