Prompt file imported from ArulaAI/copilot-engineering-test-optimization-lab-angular (.github/prompts/generate-boundary-tests.prompt.md). Copyright stays with the author.

Generate Boundary Value Tests

Create thorough boundary tests using the 7-point analysis method.

Prerequisites

Reference the boundary gaps in #file:docs/TEST_ANALYSIS.md.

7-Point Boundary Analysis

For each boundary, test these 7 values:

1. min - 1 (invalid, just below minimum)
2. min (valid, at minimum)
3. min + 1 (valid, just above minimum)
4. typical (valid, normal value)
5. max - 1 (valid, just below maximum)
6. max (valid, at maximum)
7. max + 1 (invalid, just above maximum)

Instructions

Document Boundaries as Constants

const BOUNDARIES = {
  AMOUNT_MIN: 0.01,
  AMOUNT_MAX: 999999.99,
  QUANTITY_MIN: 1,
  QUANTITY_MAX: 9999,
  NAME_MIN_LENGTH: 1,
  NAME_MAX_LENGTH: 100,
} as const;

Testing Pattern

describe('amount validation', () => {
  test.each([
    [0, false, 'below minimum'],
    [0.01, true, 'at minimum'],
    [0.02, true, 'just above minimum'],
    [500, true, 'typical value'],
    [999999.98, true, 'just below maximum'],
    [999999.99, true, 'at maximum'],
    [1000000, false, 'above maximum'],
  ])('amount %s is valid=%s (%s)', (amount, expected, reason) => {
    expect(validator.isValidAmount(amount)).toBe(expected);
  });
});

// Include null/undefined/NaN handling
describe('handles edge cases', () => {
  test.each([
    [null, false, 'null'],
    [undefined, false, 'undefined'],
    [NaN, false, 'NaN'],
    [Infinity, false, 'Infinity'],
    [-Infinity, false, '-Infinity'],
    ['100', false, 'string number'],
  ])('rejects %s (%s)', (value, expected, reason) => {
    expect(validator.isValidAmount(value as any)).toBe(expected);
  });
});

Reference: .golden-examples/boundary-testing/

Boundary Categories

1. Numeric Values: amounts, quantities, percentages, ages
2. String Lengths: names, descriptions, codes, identifiers
3. Collection Sizes: list items, array elements, batch sizes
4. Date/Time: past dates, future dates, time ranges
5. Special Values: null, empty, whitespace, zero

Output

Generate tests that document boundaries as constants and test all 7 points for each boundary identified.