docker-modem-mock

A mock implementation of docker-modem for testing purposes. This package allows you to mock Docker API calls in your tests when your code interacts with Docker (e.g., creating containers), but you don't need a real Docker daemon or to test the actual container contents.

Features

• Image Management: Pulling, building, listing, inspecting, and deleting images.
• Container Lifecycle: Creating, starting, stopping, listing, and inspecting containers.
• Fixture-based Responses: Use pre-recorded or custom fixtures to simulate Docker API responses for complex operations like pull and build.
• Dockerode Integration: Seamlessly works with dockerode by replacing its underlying modem.

Installation

npm install docker-modem-mock --save-dev

Usage

Basic Setup with Dockerode

import Docker from "dockerode";
import { ModemMock, Fixtures } from "docker-modem-mock";

const docker = new Docker({
    modem: new ModemMock({
        mockFixtures: Fixtures.fromPath("./test/fixtures")
    })
});

Pulling an Image

const stream = await docker.pull("node:18");
stream.on("data", (chunk) => console.log(chunk.toString()));
stream.on("end", () => console.log("Pull complete"));

Building an Image

const stream = await docker.buildImage({
    context: "./path/to/context",
    src: ["Dockerfile", "index.js"]
}, {
    t: "my-image:latest"
});

Container Lifecycle

const container = await docker.createContainer({
    Image: "node:18",
    name: "my-container"
});

await container.start();
const inspect = await container.inspect();

console.log(inspect.State.Status); // "running"

await container.stop();

Fixtures Structure

The mock relies on a specific directory structure for fixtures:

• records/{version}/image/{imageName}/{tag}.json: JSON file containing image inspection data.
• records/{version}/pull/{imageName}/{tag}.jsonl: JSONL file containing streaming output for image pull.
• records/{version}/build-{builderVersion}/{imageName}/{tag}.jsonl: JSONL file containing streaming output for image build.

API

ModemMock

Inherits from Modem.

• constructor(options: Options)
  • mockFixtures: Optional Fixtures instance to load initial data.
• registerFixtures(fixtures: Fixtures): Registers additional fixtures.
• reset(): Resets the internal state (containers and images).

Fixtures

• static fromPath(path: string): Creates a Fixtures instance from a filesystem path.
• static fromFS(fs: FileSystem): Creates a Fixtures instance from a @wocker/core FileSystem.

License

MIT