Testing Blocks

Danger

The create engine is only partially implemented. This site is “documentation-driven development”: writing the docs first, to help inform implementation.

The create-testers package will include testing utilities that provide mock data to a block under test.

For example, this test asserts that an nvmrc block creates an ".nvmrc" file with content "20.12.2":

import { createMockBlockContext } from "create-testers";

import { blockNvmrc } from "./blockNvmrc";

describe("blockNvmrc", () => {
  it("returns an .nvmrc", () => {
    const context = createMockBlockContext();

    const actual = await blockNvmrc(context);

    expect(actual).toEqual({ ".nvmrc": "20.12.2" });
  });
});

Options

Block options may also be provided through createMockBlockContext().

This test asserts that a Prettier block adds config options to its output ".prettierrc.json":

import { createMockBlockContext } from "create-testers";

import { blockPrettier } from "./blockPrettier";

describe("blockPrettier", () => {
  it("creates a .prettierrc.json when provided options", () => {
    const prettierConfig = {
      useTabs: true,
    };
    const context = createMockBlockContext({
      options: {
        config: prettierConfig,
      },
    });

    const actual = await blockPrettier(context);

    expect(actual).toEqual({
      files: {
        ".prettierrc.json": JSON.stringify({
          $schema: "http://json.schemastore.org/prettierrc",
          ...prettierConfig,
        }),
      },
      packages: {
        devDependencies: ["prettier"],
      },
      scripts: {
        format: "prettier .",
      },
    });
  });
});