testserver: use listening URL file to get SQL URL

[benesch]

Use the new --listening-url-file flag to specify a file in which the SQL URL will be written. This flag was added in cockroachdb/cockroach#15468 for exactly this purpose, and makes this testserver resilient to changes in what log output is printed where. Closes #29.

/cc @knz this solves the problem rather neatly :). Really we should never have been parsing stdout.

---

This change is 

[tamird]

Forgot I just merged that 🤦‍♀️

---

Reviewed 1 of 1 files at r1.
Review status: all files reviewed at latest revision, 2 unresolved discussions.

---

testserver/testserver.go, line 76 at r1 (raw file):

	// Import postgres driver.

why the newline?

---

testserver/testserver.go, line 252 at r1 (raw file):

		ts.mu.Lock()
		if ts.state != stateRunning {
			return fmt.Errorf("server stopped or crashed before listening URL file was available")

this returns without unlocking, which doesn't seem great?

---

Comments from Reviewable

[benesch]

Yeah, I thought it was pretty hilarious you sheparded that PR.

---

Review status: 0 of 1 files reviewed at latest revision, 2 unresolved discussions.

---

testserver/testserver.go, line 76 at r1 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

why the newline?

Oops. Thanks.

---

testserver/testserver.go, line 252 at r1 (raw file):

Previously, tamird (Tamir Duberstein) wrote…

this returns without unlocking, which doesn't seem great?

Eek! Thanks, fixed.

---

Comments from Reviewable

[tamird]

Reviewed 1 of 1 files at r2.
Review status: all files reviewed at latest revision, 1 unresolved discussion.

---

testserver/testserver.go, line 76 at r1 (raw file):

Previously, benesch (Nikhil Benesch) wrote…

Oops. Thanks.

I think you left it =/

---

Comments from Reviewable

[benesch]

Eep, so I did. See #33.