refactor: add LATEST_VERSION constant in code for global changing latest version on some value.

Change `latest` version on `4.0.3` 😂 cause latest version download with 403 status code.

Related #131

Author: nodkz

src/util/MongoBinary.js

@@ -11,6 +11,11 @@ import dedent from 'dedent';
 import { promisify } from 'util';
 import MongoBinaryDownload from './MongoBinaryDownload';
 
+// TODO: return back `latest` version when it will be fixed in MongoDB distro (for now use 4.0.3 😂)
+// More details in https://github.com/nodkz/mongodb-memory-server/issues/131
+// export const LATEST_VERSION = 'latest';
+export const LATEST_VERSION = '4.0.3';
+
 export type MongoBinaryCache = {
   [version: string]: string,
 };
@@ -122,7 +127,7 @@ export default class MongoBinary {
             )),
       platform: process.env?.MONGOMS_PLATFORM || os.platform(),
       arch: process.env?.MONGOMS_ARCH || os.arch(),
-      version: process.env?.MONGOMS_VERSION || 'latest',
+      version: process.env?.MONGOMS_VERSION || LATEST_VERSION,
       systemBinary: process.env?.MONGOMS_SYSTEM_BINARY,
       debug:
         typeof process.env.MONGOMS_DEBUG === 'string'
@@ -155,7 +160,7 @@ export default class MongoBinary {
           .split('\n')[0]
           .split(' ')[2];
 
-        if (version !== 'latest' && version !== binaryVersion) {
+        if (version !== LATEST_VERSION && version !== binaryVersion) {
           // we will log the version number of the system binary and the version requested so the user can see the difference
           this.debug(dedent`
             MongoMemoryServer: Possible version conflict

src/util/MongoBinaryDownload.js

@@ -11,6 +11,7 @@ import HttpsProxyAgent from 'https-proxy-agent';
 import decompress from 'decompress'; // 💩💩💩 this package does not work with Node@11+Jest+Babel
 import MongoBinaryDownloadUrl from './MongoBinaryDownloadUrl';
 import type { DebugFn, DebugPropT, DownloadProgressT } from '../types';
+import { LATEST_VERSION } from './MongoBinary';
 
 export type MongoBinaryDownloadOpts = {
   version: string,
@@ -42,7 +43,7 @@ export default class MongoBinaryDownload {
   }: $Shape<MongoBinaryDownloadOpts>) {
     this.platform = platform || os.platform();
     this.arch = arch || os.arch();
-    this.version = version || 'latest';
+    this.version = version || LATEST_VERSION;
     this.downloadDir = path.resolve(downloadDir || 'mongodb-download');
     if (checkMD5 === undefined) {
       this.checkMD5 =

src/util/__tests__/MongoBinary-test.js

@@ -3,7 +3,7 @@
 import tmp from 'tmp';
 import fs from 'fs';
 import os from 'os';
-import MongoBinary from '../MongoBinary';
+import MongoBinary, { LATEST_VERSION } from '../MongoBinary';
 
 const MongoBinaryDownload: any = require('../MongoBinaryDownload');
 
@@ -48,7 +48,7 @@ describe('MongoBinary', () => {
   describe('getDownloadPath', () => {
     it('should download binary and keep it in cache', async () => {
       // download
-      const version = 'latest';
+      const version = LATEST_VERSION;
       const binPath = await MongoBinary.getPath({
         downloadDir: tmpDir.name,
         version,

src/util/__tests__/MongoInstance-test.js

@@ -2,14 +2,10 @@
 
 import tmp from 'tmp';
 import MongoInstance from '../MongoInstance';
+import { LATEST_VERSION } from '../MongoBinary';
 
 jasmine.DEFAULT_TIMEOUT_INTERVAL = 600000;
 
-// TODO: return back `latest` version when it will be fixed in MongoDB distro (for now use 4.0.3 😂)
-// more details in https://github.com/nodkz/mongodb-memory-server/issues/131
-// const latestVersion = 'latest';
-const latestVersion = '4.0.3';
-
 let tmpDir;
 beforeEach(() => {
   tmp.setGracefulCleanup();
@@ -99,7 +95,7 @@ describe('MongoInstance', () => {
   it('should start instance on port 27333', async () => {
     const mongod = await MongoInstance.run({
       instance: { port: 27333, dbPath: tmpDir.name },
-      binary: { version: latestVersion },
+      binary: { version: LATEST_VERSION },
     });
 
     expect(mongod.getPid()).toBeGreaterThan(0);
@@ -110,13 +106,13 @@ describe('MongoInstance', () => {
   it('should throw error if port is busy', async () => {
     const mongod = await MongoInstance.run({
       instance: { port: 27444, dbPath: tmpDir.name },
-      binary: { version: latestVersion },
+      binary: { version: LATEST_VERSION },
     });
 
     await expect(
       MongoInstance.run({
         instance: { port: 27444, dbPath: tmpDir.name },
-        binary: { version: latestVersion },
+        binary: { version: LATEST_VERSION },
       })
     ).rejects.toBeDefined();
 
@@ -126,7 +122,7 @@ describe('MongoInstance', () => {
   it('should await while mongo is killed', async () => {
     const mongod = await MongoInstance.run({
       instance: { port: 27445, dbPath: tmpDir.name },
-      binary: { version: latestVersion },
+      binary: { version: LATEST_VERSION },
     });
     const pid: any = mongod.getPid();
     const killerPid: any = mongod.killerProcess.pid;