Test Case Generator

{
  "language": "python",
  "include_edge_cases": true,
  "function_description": "A function that validates a user email address format and checks if the domain exists. It takes a string parameter representing an email address and returns a boolean indicating whether the email is valid. The function should check for proper email format (local-part@domain.extension) and verify that the domain has valid MX records."
}

{
  "_meta": {
    "payment": {
      "method": "x402",
      "price_usd": 0.162,
      "settlement_id": "0x0475735be8d802bbb893ea16cbf167fda8d6aa9077ffa9faa1d9be7fe9555d4b"
    },
    "capability": "test-case-generate",
    "latency_ms": 9467,
    "provenance": {
      "source": "claude-haiku",
      "fetched_at": "2026-06-13T04:24:32.745Z"
    }
  },
  "test_cases": [
    {
      "name": "Valid email with common domain",
      "input": "user@example.com",
      "category": "happy_path",
      "description": "Standard valid email format with existing domain",
      "expected_output": true
    },
    {
      "name": "Valid email with subdomain",
      "input": "user@mail.example.com",
      "category": "happy_path",
      "description": "Valid email with subdomain in domain part",
      "expected_output": true
    },
    {
      "name": "Valid email with numbers and dots in local part",
      "input": "user.name+tag@example.co.uk",
      "category": "happy_path",
      "description": "Valid email with special characters allowed in local part",
      "expected_output": true
    },
    {
      "name": "Missing @ symbol",
      "input": "userexample.com",
      "category": "error_case",
      "description": "Email without @ separator fails validation",
      "expected_output": false
    },
    {
      "name": "Missing local part",
      "input": "@example.com",
      "category": "boundary",
      "description": "Email with empty local part is invalid",
      "expected_output": false
    },
    {
      "name": "Missing domain",
      "input": "user@",
      "category": "boundary",
      "description": "Email with empty domain is invalid",
      "expected_output": false
    },
    {
      "name": "Missing extension",
      "input": "user@example",
      "category": "boundary",
      "description": "Email without domain extension fails validation",
      "expected_output": false
    },
    {
      "name": "Empty string",
      "input": "",
      "category": "edge_case",
      "description": "Empty email string is invalid",
      "expected_output": false
    },
    {
      "name": "Spaces in email",
      "input": "user name@example.com",
      "category": "error_case",
      "description": "Email with spaces is invalid",
      "expected_output": false
    },
    {
      "name": "Multiple @ symbols",
      "input": "user@domain@example.com",
      "category": "error_case",
      "description": "Email with multiple @ symbols is invalid",
      "expected_output": false
    },
    {
      "name": "Domain with invalid MX records",
      "input": "user@invalid-domain-12345-test.com",
      "category": "edge_case",
      "description": "Email with non-existent domain fails MX record verification",
      "expected_output": false
    },
    {
      "name": "Only @ symbol",
      "input": "@",
      "category": "boundary",
      "description": "String containing only @ symbol is invalid",
      "expected_output": false
    },
    {
      "name": "Special characters in local part",
      "input": "user+filter@example.com",
      "category": "happy_path",
      "description": "Valid email with plus sign in local part",
      "expected_output": true
    },
    {
      "name": "Consecutive dots in local part",
      "input": "user..name@example.com",
      "category": "error_case",
      "description": "Email with consecutive dots in local part is invalid",
      "expected_output": false
    },
    {
      "name": "Domain with hyphen",
      "input": "user@my-domain.com",
      "category": "happy_path",
      "description": "Valid email with hyphenated domain",
      "expected_output": true
    },
    {
      "name": "Leading dot in local part",
      "input": ".user@example.com",
      "category": "boundary",
      "description": "Email starting with dot in local part is invalid",
      "expected_output": false
    },
    {
      "name": "Trailing dot in local part",
      "input": "user.@example.com",
      "category": "boundary",
      "description": "Email ending with dot in local part is invalid",
      "expected_output": false
    },
    {
      "name": "Local part too long",
      "input": "verylonglocalpartthatexceedsthemaximumlengthallowedforthelocalparthereitshouldbeabout64characters@example.com",
      "category": "boundary",
      "description": "Email with local part exceeding 64 characters is invalid",
      "expected_output": false
    },
    {
      "name": "Domain with numeric extension",
      "input": "user@example.123",
      "category": "error_case",
      "description": "Email with numeric-only extension is invalid",
      "expected_output": false
    },
    {
      "name": "Case sensitivity test - uppercase",
      "input": "USER@EXAMPLE.COM",
      "category": "edge_case",
      "description": "Email validation should be case-insensitive",
      "expected_output": true
    },
    {
      "name": "International domain",
      "input": "user@example.中国",
      "category": "edge_case",
      "description": "Email with internationalized domain name",
      "expected_output": true
    },
    {
      "name": "Domain with single character",
      "input": "user@a.com",
      "category": "boundary",
      "description": "Valid email with single-character domain",
      "expected_output": true
    }
  ],
  "total_cases": 22,
  "coverage_notes": "Coverage includes: valid email formats (happy path), missing required components (@, local part, domain, extension), special characters and dots handling, MX record verification, RFC 5321/5322 compliance for format, edge cases like empty strings, spaces, multiple @ symbols, case sensitivity, internationalized domains, length constraints, and consecutive dot validation. Potential gaps: SMTP validation, disposable email detection, real-time SMTP verification, and Unicode character validation in local parts.",
  "language_detected": "python"
}