fix unit test import

Author: syz99

src/cmap/auth/providers.ts

@@ -11,7 +11,7 @@ export const AuthMechanism = Object.freeze({
 } as const);
 
 /** @public */
-export const $EXTERNAL_AUTH_SOURCE_MECHANISMS = new Set<string | undefined>([
+export const $EXTERNAL_AUTH_SOURCE_MECHANISMS = new Set<AuthMechanism | undefined>([
   AuthMechanism.MONGODB_GSSAPI,
   AuthMechanism.MONGODB_AWS,
   AuthMechanism.MONGODB_X509

test/unit/srv_option_handling.test.ts

@@ -3,11 +3,8 @@ import * as dns from 'dns';
 import * as sinon from 'sinon';
 import { promisify } from 'util';
 
-import {
-  $EXTERNAL_AUTH_SOURCE_MECHANISMS,
-  AuthMechanism
-} from '../../src/cmap/auth/defaultAuthProviders';
 import { MongoCredentials } from '../../src/cmap/auth/mongo_credentials';
+import { $EXTERNAL_AUTH_SOURCE_MECHANISMS, AuthMechanism } from '../../src/cmap/auth/providers';
 import { resolveSRVRecord } from '../../src/connection_string';
 
 const resolveSRVRecordAsync = promisify(resolveSRVRecord);