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Testing Regular Expression Pattern Matching in javascript-algorithms

This test suite validates the functionality of a regular expression matching algorithm implementation, focusing on pattern matching capabilities and edge cases in strings. The tests cover both basic string matching and complex pattern scenarios using wildcards and quantifiers.

Test Coverage Overview

The test suite provides comprehensive coverage of regular expression matching scenarios.

Key areas tested include:

Empty string handling
Basic character matching
Wildcard (.) pattern matching
Kleene star (*) quantifier testing
Combined pattern matching with wildcards and quantifiers
Complex string patterns with multiple operators

Implementation Analysis

The testing approach employs Jest’s expect assertions to verify pattern matching outcomes. The implementation uses a systematic pattern of positive and negative test cases to ensure robust validation.

Testing patterns include:

Direct string-to-pattern comparison
Wildcard character validation
Quantifier behavior verification
Edge case handling for empty strings and patterns

Technical Details

Testing infrastructure:

Framework: Jest
Test Type: Unit tests
Pattern: Describe/It block structure
Assertion Style: Expect/toBe
File Organization: Single test suite with multiple assertions

Best Practices Demonstrated

The test suite exemplifies several testing best practices in JavaScript algorithm validation.

Notable practices include:

Comprehensive positive and negative test cases
Clear test case organization
Progressive complexity in test scenarios
Thorough edge case coverage
Consistent assertion patterns

trekhleb/javascript-algorithms

src/algorithms/string/regular-expression-matching/__test__/regularExpressionMatching.test.js

            
import regularExpressionMatching from '../regularExpressionMatching';

describe('regularExpressionMatching', () => {
  it('should match regular expressions in a string', () => {
    expect(regularExpressionMatching('', '')).toBe(true);
    expect(regularExpressionMatching('a', 'a')).toBe(true);
    expect(regularExpressionMatching('aa', 'aa')).toBe(true);
    expect(regularExpressionMatching('aab', 'aab')).toBe(true);
    expect(regularExpressionMatching('aab', 'aa.')).toBe(true);
    expect(regularExpressionMatching('aab', '.a.')).toBe(true);
    expect(regularExpressionMatching('aab', '...')).toBe(true);
    expect(regularExpressionMatching('a', 'a*')).toBe(true);
    expect(regularExpressionMatching('aaa', 'a*')).toBe(true);
    expect(regularExpressionMatching('aaab', 'a*b')).toBe(true);
    expect(regularExpressionMatching('aaabb', 'a*b*')).toBe(true);
    expect(regularExpressionMatching('aaabb', 'a*b*c*')).toBe(true);
    expect(regularExpressionMatching('', 'a*')).toBe(true);
    expect(regularExpressionMatching('xaabyc', 'xa*b.c')).toBe(true);
    expect(regularExpressionMatching('aab', 'c*a*b*')).toBe(true);
    expect(regularExpressionMatching('mississippi', 'mis*is*.p*.')).toBe(true);
    expect(regularExpressionMatching('ab', '.*')).toBe(true);

    expect(regularExpressionMatching('', 'a')).toBe(false);
    expect(regularExpressionMatching('a', '')).toBe(false);
    expect(regularExpressionMatching('aab', 'aa')).toBe(false);
    expect(regularExpressionMatching('aab', 'baa')).toBe(false);
    expect(regularExpressionMatching('aabc', '...')).toBe(false);
    expect(regularExpressionMatching('aaabbdd', 'a*b*c*')).toBe(false);
    expect(regularExpressionMatching('mississippi', 'mis*is*p*.')).toBe(false);
    expect(regularExpressionMatching('ab', 'a*')).toBe(false);
    expect(regularExpressionMatching('abba', 'a*b*.c')).toBe(false);
    expect(regularExpressionMatching('abba', '.*c')).toBe(false);
  });
});