request: Start server only if it is not running.

[FDiskas]

If I already have running local server on port 1234
I was sure that start-server-and-test :1234 'cypress open --e2e --browser chrome' first will check if it is not running already before starting the local server.

Why this is not the case?

[benzado]

How can it know if a server is already running? It could try connecting to the port, but that only confirms that something is listening... it could be a server from a different project!

I like that start-server-and-test will take ownership of the test server and terminates it when the tests are done. If it becomes too clever about using already running servers, it becomes too complex.

If your test server and development server are frequently fighting over the same port, may I suggest using a different port number for testing? You can even use a random port each time with a script like this:

#!/bin/bash

export PORT=$RANDOM
export CYPRESS_BASE_URL="http://localhost:$PORT"
npm exec -c "start-server-and-test start :$PORT 'cypress open'"

[adrianbienias]

Using curl and grep you can check if the URL, that you expect dev server to be running on, responds with 200 code.
And if not, then you can start dev server.

With npm script it can be something like the following:

"dev": "node server.js",
"cy:run": "cypress run",
"check-server": "curl -s -o /dev/null -w '%{http_code}' http://localhost:3000 | grep 200 || npm run dev",
"test": "start-server-and-test check-server 3000 cy:run",