Understanding Test Cases in Coding Assessments

Overview

Test cases are used to automatically evaluate a candidate’s code during a coding assessment. They help determine whether the submitted solution works correctly for different inputs and scenarios.

What is a Test Case?

A test case consists of:

• Input: Data provided to the candidate’s program.
• Expected Output: The correct result that the program should produce for the given input.
• Validation Logic: A mechanism that compares the candidate’s output with the expected output.

The candidate’s solution is executed against one or more test cases to verify correctness.

Types of Test Cases

Sample Test Cases

Sample test cases are visible to candidates during the assessment.

Purpose:

• Help candidates understand the problem statement.
• Demonstrate the expected input and output format.
• Allow candidates to test their code before submission.

Example:

Input:

5

Output:

25

Hidden Test Cases

Hidden test cases are not displayed to candidates.

Purpose:

• Validate solutions against additional scenarios.
• Prevent hardcoded answers.
• Ensure the solution works for all valid inputs.

Candidates only see whether their code passes or fails these test cases.

How Test Cases are Evaluated

1. Candidate submits code.
2. The system compiles the solution.
3. The code runs against all configured test cases.
4. Actual output is compared with expected output.
5. Scores are awarded based on the number of test cases passed.

Why Did My Solution Fail?

Common reasons include:

• Incorrect logic.
• Wrong input/output format.
• Missing edge case handling.
• Runtime errors.
• Compilation errors.
• Exceeding time or memory limits.

Best Practices for Candidates

• Carefully read the problem statement.
• Match the required input and output format exactly.
• Test with sample inputs before submission.
• Handle edge cases and boundary conditions.
• Avoid hardcoding outputs.

Frequently Asked Questions

Can I see all test cases?

No. Only sample test cases are visible. Hidden test cases are used to ensure fair evaluation.

Why does my code pass sample test cases but fail overall?

Sample test cases cover only a few scenarios. Hidden test cases may include larger inputs, edge cases, or different data patterns.

Does formatting matter?

Yes. Extra spaces, missing lines, or incorrect output formatting can cause test case failures.

What happens if my code does not compile?

The assessment system will mark the submission as a compilation error, and test cases will not be executed.

Are test cases different for different candidates?

Typically, all candidates receive the same set of test cases for a particular coding question to ensure consistent evaluation.

Summary

Test cases are an essential part of coding assessments. They verify the correctness, efficiency, and robustness of a candidate’s solution by checking it against predefined inputs and expected outputs.