diff --git a/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.test.ts b/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.test.ts
index ff151d94ecd53..17df757375a8e 100644
--- a/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.test.ts
+++ b/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.test.ts
@@ -19,11 +19,11 @@ import path from 'path';
 
 import { resolveNetworkAddress } from './resolveNetworkAddress';
 
-// Hardcoded in testProcess.js.
+// Hardcoded in testProcess.mjs.
 const PORT = '1337';
 
 it('returns an error when supplied an unknown protocol', async () => {
-  const process = fork(path.join(__dirname, 'testProcess.js'), {
+  const process = fork(path.join(__dirname, 'testProcess.mjs'), {
     silent: true,
   });
 
@@ -56,7 +56,7 @@ describe.each(testSuites)(
   'for $name process',
   ({ requestedAddress, expectedNetworkAddress }) => {
     it(`waits for the process to output the matching string`, async () => {
-      const process = fork(path.join(__dirname, 'testProcess.js'), {
+      const process = fork(path.join(__dirname, 'testProcess.mjs'), {
         silent: true,
       });
 
@@ -73,7 +73,7 @@ describe.each(testSuites)(
     });
 
     it(`times out if the process doesn't return the match in time`, async () => {
-      const process = fork(path.join(__dirname, 'testProcess.js'), ['100'], {
+      const process = fork(path.join(__dirname, 'testProcess.mjs'), ['100'], {
         silent: true,
       });
 
@@ -88,7 +88,7 @@ describe.each(testSuites)(
 
     it(`returns an error if the process exits without returning a match`, async () => {
       const process = fork(
-        path.join(__dirname, 'testProcess.js'),
+        path.join(__dirname, 'testProcess.mjs'),
         ['10', 'exit-prematurely'],
         {
           silent: true,
diff --git a/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.ts b/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.ts
index 73bb5f617e1b7..db4c806fd7972 100644
--- a/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.ts
+++ b/web/packages/teleterm/src/mainProcess/resolveNetworkAddress.ts
@@ -99,7 +99,8 @@ function waitForMatchInStdout(
 
     const rejectOnExit = (code: number, signal: NodeJS.Signals) => {
       const codeOrSignal = [
-        code && `code ${code}`,
+        // code can be 0, so we cannot just check it the same way as the signal.
+        code != null && `code ${code}`,
         signal && `signal ${signal}`,
       ]
         .filter(Boolean)
diff --git a/web/packages/teleterm/src/mainProcess/testProcess.js b/web/packages/teleterm/src/mainProcess/testProcess.js
deleted file mode 100644
index ae3ead2efb9b0..0000000000000
--- a/web/packages/teleterm/src/mainProcess/testProcess.js
+++ /dev/null
@@ -1,19 +0,0 @@
-const process = require('process');
-
-const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
-
-(async () => {
-  const waitTime = parseInt(process.argv[2]);
-  if (waitTime) {
-    await sleep(waitTime);
-  }
-
-  const shouldExit = process.argv[3];
-  if (shouldExit) {
-    process.exit(1);
-  }
-
-  console.log('Lorem ipsum dolor sit amet');
-  console.log('{CONNECT_GRPC_PORT: 1337}');
-  console.log('Lorem ipsum dolor sit amet');
-})();
diff --git a/web/packages/teleterm/src/mainProcess/testProcess.mjs b/web/packages/teleterm/src/mainProcess/testProcess.mjs
new file mode 100644
index 0000000000000..bb8b540a5df8c
--- /dev/null
+++ b/web/packages/teleterm/src/mainProcess/testProcess.mjs
@@ -0,0 +1,33 @@
+/**
+ * Copyright 2023 Gravitational, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import process from 'process';
+
+const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
+
+const waitTime = parseInt(process.argv[2]);
+if (waitTime) {
+  await sleep(waitTime);
+}
+
+const shouldExit = process.argv[3];
+if (shouldExit) {
+  process.exit(1);
+}
+
+console.log('Lorem ipsum dolor sit amet');
+console.log('{CONNECT_GRPC_PORT: 1337}');
+console.log('Lorem ipsum dolor sit amet');