Practical Guide to Writing Test Cases for Java DSA Problems

Writing good test cases is a critical part of mastering data structures and algorithms. In this guide, we will cover:

✅ Why Test Cases Matter

Many students ignore unit testing during DSA practice — but writing test cases ensures your logic works for:

• Edge cases
• Boundary conditions
• Performance on large inputs

✅ Sample: Reverse a Linked List

@Test
public void testReverseLinkedList() {
    ListNode input = createList(new int[]{1, 2, 3, 4});
    ListNode expected = createList(new int[]{4, 3, 2, 1});
    assertTrue(compareLists(expected, reverseList(input)));
}