try fix port usage for e2e dog fooding tests

Author: gallayl

e2e/dogfooding.spec.ts

@@ -6,6 +6,7 @@ import {
   deleteStack,
   expectNotification,
   fillServiceForm,
+  getAvailablePort,
   login,
   navigateToCreateService,
   submitServiceForm,
@@ -43,7 +44,8 @@ It is used to test the following features:
 
   `
 
-  const dogfoodingPort = browserName === 'chromium' ? 19090 : 19091
+  const dogfoodingPort = await getAvailablePort()
+  const mcpPort = await getAvailablePort()
   const workingDirectory = `/tmp/e2e-dog-fooding-time-${uuid}`
 
   await page.goto('/')
@@ -160,7 +162,7 @@ It is used to test the following features:
       const mcpSourceSelect = mcpOverride.locator('shade-select').first()
       await mcpSourceSelect.locator('.select-trigger').click()
       await mcpSourceSelect.locator('.dropdown-item', { hasText: 'Custom value' }).click()
-      await mcpOverride.locator('shade-input input').fill(String(dogfoodingPort + 1))
+      await mcpOverride.locator('shade-input input').fill(String(mcpPort))
 
       // Save the overrides and wait for the save to complete
       const saveButton = page.getByTestId('save-env-overrides')

e2e/helpers/get-available-port.ts

@@ -0,0 +1,12 @@
+import { createServer } from 'net'
+
+/** Binds to port 0 so the OS assigns a free port, then closes the server and returns the port number */
+export const getAvailablePort = (): Promise<number> =>
+  new Promise((resolve, reject) => {
+    const server = createServer()
+    server.listen(0, () => {
+      const { port } = server.address() as { port: number }
+      server.close(() => resolve(port))
+    })
+    server.on('error', reject)
+  })

e2e/helpers/index.ts

@@ -1,3 +1,4 @@
+export { getAvailablePort } from './get-available-port.js'
 export { login } from './login.js'
 export { expectNotification } from './notification.js'
 export { addPrerequisite, type PrerequisiteParams } from './prerequisite.js'