@firestore-emulator/jest/src/environment/node.ts

This package contains a [`Jest`](https://jestjs.io/) environment for setup `@firestore-emulator/server`.

import { FirestoreServer } from "@firestore-emulator/server";
import type {
  EnvironmentContext,
  JestEnvironmentConfig,
} from "@jest/environment";
import { findFreePorts } from "find-free-ports";
import { TestEnvironment } from "jest-environment-node";

import type { FirestoreEmulatorEnvironmentConfig } from "../types";

export default class FirestoreEmulatorEnvironment extends TestEnvironment {
  private server: FirestoreServer;

  constructor(
    config: FirestoreEmulatorEnvironmentConfig & JestEnvironmentConfig,
    context: EnvironmentContext,
  ) {
    super(config, context);
    this.server = new FirestoreServer();
  }

  override async setup() {
    await super.setup();

    let tryCount = 0;
    while (tryCount < 50) {
      const [port] = await findFreePorts(1);
      if (!port) throw new Error("Could not find a free port");
      try {
        await this.server.start(port);
        this.global.emulator = {
          host: `0.0.0.0:${port}`,
          port,
          state: this.server.state,
        };
        return;
      } catch (err) {
        if (!(err instanceof Error)) throw err;
        if (!err.message.startsWith("No address added out of total")) throw err;
      }
      tryCount++;
    }
    throw new Error("Could not find a free port");
  }

  override async teardown() {
    this.server.stop();
    await super.teardown();
  }
}