fakerz

A simple Zig library for generating fake data for testing. If you've ever needed random strings, test data, or placeholder values in your Zig projects, this is for you.

Quick Start

Add fakerz to your project:

zig fetch --save git+https://github.com/pierrelgol/fakerz#main

Then in your build.zig, add it as a dependency:

const fakerz_dep = b.dependency("fakerz", .{
    .target = target,
    .optimize = optimize,
});

const fakerz = fakerz_dep.module("fakerz");
exe.root_module.addImport("fakerz", fakerz);

Example

const std = @import("std");
const fakerz = @import("fakerz");

pub fn main() !void {
    var prng = std.Random.DefaultPrng.init(12345);
    const rand = prng.random();

    // Generate a random string of 20 letters
    var username: [20]u8 = undefined;
    fakerz.text.string.alpha(rand, &username);
    std.debug.print("Username: {s}\n", .{username});

    // Generate random digits for a fake ID
    var id: [10]u8 = undefined;
    fakerz.text.string.digit(rand, &id);
    std.debug.print("ID: {s}\n", .{id});

    // Generate random hex for a fake session token
    var token: [32]u8 = undefined;
    fakerz.text.string.hex(rand, &token);
    std.debug.print("Token: {s}\n", .{token});

    // Mix things up with alphanumeric
    var password: [16]u8 = undefined;
    fakerz.text.string.alnum(rand, &password);
    std.debug.print("Password: {s}\n", .{password});
}

What can you do with it?

Basic String Generation

Fill buffers with different types of characters:

• alpha() - Random letters (a-z, A-Z)
• upper() / lower() - Uppercase or lowercase only
• digit() - Numbers 0-9
• alnum() - Letters and numbers mixed
• hex() - Hexadecimal characters
• ascii() / printable() / visible() - Various ASCII ranges
• identifier() - Valid identifier characters (great for variable names)
• vowel() / consonant() - Just vowels or consonants

Special Characters

• punctuation() - Punctuation marks
• symbol() - Various symbols
• bracket() / quote() - Brackets and quotes
• whitespace() - Spaces, tabs, newlines

Advanced Patterns

// Repeat a pattern
var buf: [40]u8 = undefined;
fakerz.text.string.pattern(rand, &buf, "Aa#"); // Repeats "Aa#Aa#Aa#..."

// Fill from a custom character set
fakerz.text.string.fromCharset(rand, &buf, "!@#$%^&*");

// Shuffle existing data
fakerz.text.string.shuffle(rand, &buf);

// Create gradients (useful for test patterns)
fakerz.text.string.gradientHorizontal(&buf, 'A', 'Z'); // A...Z gradient

2D Grids

Need to generate test data for grids or matrices?

const allocator = std.heap.page_allocator;
var grid = try allocator.alloc([]u8, 10);
for (grid) |*row| {
    row.* = try allocator.alloc(u8, 10);
}
defer {
    for (grid) |row| allocator.free(row);
    allocator.free(grid);
}

// Fill with random letters
fakerz.text.string.fill2D(rand, grid, fakerz.text.byte.alpha);

// Add a border
fakerz.text.string.border(grid, '*');

// Create gradients
fakerz.text.string.gradientVertical(grid, 'A', 'Z');

// Shuffle the whole grid (requires a temporary buffer)
var buffer: [100]u8 = undefined;
fakerz.text.string.shuffle2D(rand, grid, &buffer);

Kind Enum (Type-Safe Generation)

Use the Kind enum for more flexibility:

const kind = fakerz.text.string.Kind.alphaNumeric;
fakerz.text.string.fill(rand, &buf, kind);

// Or generate single bytes
const random_vowel = fakerz.text.string.generateByte(rand, .vowel);

How it Works

All generation functions take std.Random as the first parameter, which means:

• You control the random seed (great for reproducible tests)
• No global state
• Easy to test and mock

Most functions fill buffers you provide, so you control memory allocation. No surprises.

Building

# Build the project
zig build

# Run tests
zig build test

# Run the demo
zig build run

License

This project is in early development (v0.0.0). Use at your own risk, but have fun!