tests: decouple fake server from MYSQL_HOST

Fake servers are being created on the host specified by the MYSQL_HOST
environment variable. This can lead to issues when the real MySQL server
instance used for the integration tests is not running on the same host,
for instance, in Docker-based CI environments.

This patch ensures fake servers are explicitely created in the
host/container where the test suite is running.

Author: ruiquelhas

test/integration/connection/test-disconnects.js

@@ -1,3 +1,10 @@
+// This file was modified by Oracle on January 21, 2021.
+// The connection with the mock server needs to happen in the same host where
+// the tests are running in order to avoid connecting a potential MySQL server
+// instance running in the host identified by the MYSQL_HOST environment
+// variable.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
 'use strict';
 
 const common = require('../../common');
@@ -10,7 +17,14 @@ const connections = [];
 
 const server = common.createServer(
   () => {
-    const connection = common.createConnection({ port: server._port });
+    const connection = common.createConnection({
+      // The mock server is running on the same host machine.
+      // We need to explicitly define the host to avoid connecting to a potential
+      // different host provided via MYSQL_HOST that identifies a real MySQL
+      // server instance.
+      host: 'localhost',
+      port: server._port
+    });
     connection.query('SELECT 123', (err, _rows, _fields) => {
       if (err) {
         throw err;

test/integration/connection/test-protocol-errors.js

@@ -1,3 +1,10 @@
+// This file was modified by Oracle on January 21, 2021.
+// The connection with the mock server needs to happen in the same host where
+// the tests are running in order to avoid connecting a potential MySQL server
+// instance running in the host identified by the MYSQL_HOST environment
+// variable.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
 'use strict';
 
 const assert = require('assert');
@@ -9,7 +16,14 @@ let rows;
 
 const server = common.createServer(
   () => {
-    const connection = common.createConnection({ port: server._port });
+    const connection = common.createConnection({
+      // The mock server is running on the same host machine.
+      // We need to explicitly define the host to avoid connecting to a potential
+      // different host provided via MYSQL_HOST that identifies a real MySQL
+      // server instance.
+      host: 'localhost',
+      port: server._port
+    });
     connection.query(query, (err, _rows, _fields) => {
       if (err) {
         throw err;

test/integration/connection/test-quit.js

@@ -1,3 +1,10 @@
+// This file was modified by Oracle on January 21, 2021.
+// The connection with the mock server needs to happen in the same host where
+// the tests are running in order to avoid connecting a potential MySQL server
+// instance running in the host identified by the MYSQL_HOST environment
+// variable.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
 'use strict';
 
 const assert = require('assert');
@@ -9,7 +16,14 @@ let rows;
 let fields;
 const server = common.createServer(
   () => {
-    const connection = common.createConnection({ port: server._port });
+    const connection = common.createConnection({
+      // The mock server is running on the same host machine.
+      // We need to explicitly define the host to avoid connecting to a potential
+      // different host provided via MYSQL_HOST that identifies a real MySQL
+      // server instance.
+      host: 'localhost',
+      port: server._port
+    });
 
     connection.query(queryCli, (err, _rows, _fields) => {
       if (err) {

test/integration/connection/test-stream-errors.js

@@ -1,3 +1,10 @@
+// This file was modified by Oracle on January 21, 2021.
+// The connection with the mock server needs to happen in the same host where
+// the tests are running in order to avoid connecting a potential MySQL server
+// instance running in the host identified by the MYSQL_HOST environment
+// variable.
+// Modifications copyright (c) 2021, Oracle and/or its affiliates.
+
 'use strict';
 
 const assert = require('assert');
@@ -12,7 +19,14 @@ const query = 'SELECT 1';
 
 const server = common.createServer(
   () => {
-    clientConnection = common.createConnection({ port: server._port });
+    clientConnection = common.createConnection({
+      // The mock server is running on the same host machine.
+      // We need to explicitly define the host to avoid connecting to a potential
+      // different host provided via MYSQL_HOST that identifies a real MySQL
+      // server instance.
+      host: 'localhost',
+      port: server._port
+    });
     clientConnection.query(query, err => {
       receivedError1 = err;
     });