Test-data generators

Writing tests against validators needs valid inputs — but you must never use a real person’s PAN or Aadhaar in a test. indycheck’s generators produce random values that pass validation, for tests, demos, screenshots and seed data.

Generators exist for PAN, Aadhaar, GSTIN, mobile and vehicle only. IFSC, UPI, PIN code, TAN, CIN, LLPIN and Voter ID have validators but no generators yet — use fixed test strings from their docs pages (for example SBIN0000123 for IFSC).

Usage

import { generatePan, generateAadhaar, generateGstin, generateMobile, generateVehicle, generateVehicleBharat } from 'indycheck';

generatePan('P');        // e.g. 'HMSTC9464C'  — random every time
generateAadhaar();       // e.g. '262200939149' — passes Verhoeff
generateGstin('18');     // e.g. '13NFAPJ0888B1ZM' — passes Mod-36 Luhn
generateMobile();        // e.g. '6308893624'
generateVehicle();       // e.g. 'TN02D6788' — state format
generateVehicleBharat(); // e.g. '22BH1234AA' — Bharat (BH) format

from indycheck import generate_pan, generate_vehicle, validate_pan

pan = generate_pan("P")            # e.g. 'HMSTC9464C'
vehicle = generate_vehicle()       # e.g. 'TN02D6788'
assert validate_pan(pan)["valid"] is True

use indycheck::{generate_pan, generate_vehicle};

let pan = generate_pan('P');       // e.g. "HMSTC9464C"
let vehicle = generate_vehicle();  // e.g. "TN02D6788"

What the generators produce

Type	Example output	Guarantee
PAN	`HMSTC9464C`	Valid format (entity reported)
Aadhaar	`262200939149`	Passes the Verhoeff checksum
GSTIN	`13NFAPJ0888B1ZM`	Valid state, valid PAN part, correct Mod-36 Luhn check char
Mobile	`6308893624`	10 digits, starts 6–9
Vehicle (state)	`TN02D6788`	Valid state format (state code + district + series + number)
Vehicle (Bharat)	`22BH1234AA`	Valid Bharat format (year 21+, `BH`, number 0001–9999, suffix without `I`/`O`)

Every generated value passes its own validator — this is covered by tests in the package.

Patterns for tests

import { describe, it, expect } from 'vitest';
import { generatePan, validatePan } from 'indycheck';

describe('signup form', () => {
  it('accepts a generated PAN', () => {
    const pan = generatePan('P');
    expect(validatePan(pan).valid).toBe(true);
  });

  it('rejects a PAN with a broken format', () => {
    // Flip the last character of a valid PAN to a digit — the shape
    // no longer matches 5 letters + 4 digits + 1 letter. (PAN has no
    // checksum, and the 4th character is reported, not enforced — so
    // corrupting the holder-type character would still validate.)
    const pan = generatePan('P');
    const bad = pan.slice(0, 9) + '5';
    expect(validatePan(bad).code).toBe('INVALID_FORMAT');
  });
});

from indycheck import generate_aadhaar, generate_gstin, validate_aadhaar, validate_gstin

def test_generated_aadhaar_is_valid():
    assert validate_aadhaar(generate_aadhaar())["valid"] is True

def test_generated_gstin_round_trips():
    gstin = generate_gstin("18")
    assert validate_gstin(gstin)["parsed"]["state"]

Seeding a demo database

import { generatePan, generateMobile } from 'indycheck';

const demoCustomers = Array.from({ length: 20 }, (_, i) => ({
  id: i + 1,
  name: `Demo Customer ${i + 1}`,
  pan: generatePan('P'),
  mobile: generateMobile(),
  // Label the row so nobody mistakes it for real data:
  is_test_data: true,
}));

⚠️ TEST DATA ONLY — read this