Robust Regression Detection in Jest

Regression testing is crucial for maintaining software quality. This challenge asks you to implement a Jest test suite that automatically detects regressions in a simple function. You'll be provided with a baseline set of inputs and expected outputs, and your task is to create tests that flag any deviations from this baseline after a code change.

Problem Description

You are given a function add that performs a simple addition operation. Your goal is to create a Jest test suite that verifies the function's behavior against a predefined baseline. The test suite should:

1. Establish a Baseline: The baseline consists of a set of input-output pairs. These pairs represent the expected behavior of the add function.
2. Detect Regressions: After any modification to the add function, the test suite should automatically detect if the function's output for any of the baseline inputs has changed. A regression is flagged if the actual output differs from the expected output.
3. Provide Clear Failure Messages: When a regression is detected, the test suite should provide a clear and informative failure message indicating the input that caused the regression and the expected vs. actual output.
4. Handle Edge Cases: Consider cases where the inputs might be zero or negative.

The add function is defined as follows:

function add(a: number, b: number): number {
  return a + b;
}

Examples

Example 1:

Input:  add(2, 3)
Output: 5
Explanation:  The function should correctly add 2 and 3.

Example 2:

Input:  add(-1, 1)
Output: 0
Explanation:  The function should handle negative numbers correctly.

Example 3:

Input:  add(0, 0)
Output: 0
Explanation:  The function should handle zero inputs correctly.

Constraints

• The add function will only accept numeric inputs (integers or floating-point numbers).
• The test suite should cover at least the examples provided above, plus at least three additional test cases with different combinations of positive, negative, and zero inputs.
• The test suite should be written in TypeScript and use Jest.
• The test suite should be designed to be easily extensible to accommodate more baseline inputs in the future.
• The test suite should be robust and not prone to false positives (i.e., flagging changes that are not actual regressions).

Notes

• Consider using a data-driven testing approach (e.g., test.each) in Jest to efficiently test multiple input-output pairs.
• Focus on creating a clear and maintainable test suite that effectively detects regressions.
• Think about how to structure your test cases to ensure good code coverage.
• The baseline data should be hardcoded within the test suite for simplicity. No external data files are required.
• The goal is to detect any deviation from the baseline, not to optimize for performance. Readability and maintainability are prioritized.