preuninstall.ts

import { assert } from "chai";

// Use require instead of import in order to replace the `spawn` method of child_process
const childProcess = require("child_process");

import { SpawnOptions, ChildProcess } from "child_process";
import * as path from "path";
import { EventEmitter } from "events";

describe("preuninstall.js", () => {
	let isSpawnCalled = false;
	let argsPassedToSpawn: string[] = [];
	let optionsPassedToSpawn: any[];
	let dataPassedToConsoleError: string[] = [];
	const originalSpawn = childProcess.spawn;
	const originalConsoleError = console.error;
	let eventEmitter = new EventEmitter();

	beforeEach(() => {
		isSpawnCalled = false;
		argsPassedToSpawn = [];
		dataPassedToConsoleError = [];
		optionsPassedToSpawn = [];
		eventEmitter = new EventEmitter();
		childProcess.spawn = (command: string, args?: string[], options?: SpawnOptions): ChildProcess => {
			isSpawnCalled = true;
			argsPassedToSpawn = args;
			optionsPassedToSpawn.push(options);
			return <any>eventEmitter;
		};

		console.error = (data: string) => {
			dataPassedToConsoleError.push(data);
		};
	});

	afterEach(() => {
		childProcess.spawn = originalSpawn;
		console.error = originalConsoleError;
	});

	it("calls dev-preuninstall command of CLI and prints with console.error the error in case childProcess emits error event", () => {
		require(path.join(__dirname, "..", "preuninstall"));

		assert.isTrue(isSpawnCalled, "child_process.spawn must be called from preuninstall.js");

		const expectedPathToCliExecutable = path.join(__dirname, "..", "bin", "tns");

		assert.isTrue(argsPassedToSpawn.indexOf(expectedPathToCliExecutable) !== -1, `The spawned args must contain path to TNS.
				Expected path is: ${expectedPathToCliExecutable}, current args are: ${argsPassedToSpawn}.`);
		assert.isTrue(argsPassedToSpawn.indexOf("dev-preuninstall") !== -1, `The spawned args must contain the name of the preuninstall command.
				Expected path is: ${expectedPathToCliExecutable}, current args are: ${argsPassedToSpawn}.`);
		assert.deepEqual(optionsPassedToSpawn, [{ stdio: "inherit" }], "The stdio must be inherit as this way CLI's command can determine correctly if terminal is in interactive mode.");
		assert.deepEqual(dataPassedToConsoleError, []);

		const errMsg = "this is error message";
		eventEmitter.emit("error", new Error(errMsg));
		assert.deepEqual(dataPassedToConsoleError, [`Failed to complete all pre-uninstall steps. Error is ${errMsg}`]);
	});

	it("ensure package.json has correct preuninstall script", () => {
		const packageJsonData = require("../package.json");
		assert.equal(packageJsonData.scripts.preuninstall, "node preuninstall.js");
	});
});