mdast-util-arbitrary

Generate arbitrary, random, and valid mdast with fast-check, useful for property testing mdast utils and remark plugins.

Install

npm install --save-dev mdast-util-arbitrary

Usage

import { assert, property } from "fast-check";
import { commonmark } from "mdast-util-arbitrary";

assert(
  property(commonmark().Root, (mdast) => {
    // do something with mdast
  })
);

API

This package exports a commonmark function which returns a dictionary of node types which can be generated (usually Root should be used starting node type)

commonmark(options?: Options) => {[nodeType: string]: Arbitrary}

Options

Options.includeData

Whether to generate arbitrary data attributes for nodes. Default false.

Options.rootNodeMaxChildren

Limit the maximum number of child nodes the Root node can have. Default 100.

Example

Using uvu to test mdast-util-to-markdown.

Checking three properties of mdast-util-to-markdown:

1. it does not throw an exception on valid markdown
2. it produces a string
3. it produces non-empty markdown text

Generating 100 mdast random mdast trees to see if the properties hold true.

import { test } from "uvu";
import toString from "mdast-util-to-markdown";
import { assert, property } from "fast-check";
import { commonmark } from "mdast-util-arbitrary";

test("arbitrary mdast can be stringified", () => {
  assert(
    property(commonmark().Root, (mdast) => {
      const markdown = toString(mdast);
      return typeof markdown === "string" && markdown.length > 1;
    }),
    { numRuns: 100 }
  );
});

test.run();