chore: consolidate various randomPort() implementations (#12362)

Consolidates our existing randomPort() implementations to package testutil

enterprise/cli/provisionerdaemons_test.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"context"
 	"fmt"
-	"net"
 	"net/http"
 	"strings"
 	"testing"
@@ -170,7 +169,7 @@ func TestProvisionerDaemon_SessionToken(t *testing.T) {
 	t.Run("PrometheusEnabled", func(t *testing.T) {
 		t.Parallel()
 
-		prometheusPort := randomPort(t)
+		prometheusPort := testutil.RandomPort(t)
 
 		// Configure CLI client
 		client, admin := coderdenttest.New(t, &coderdenttest.Options{
@@ -242,13 +241,3 @@ func TestProvisionerDaemon_SessionToken(t *testing.T) {
 		require.True(t, hasPromHTTP, "Prometheus HTTP metrics are missing")
 	})
 }
-
-// randomPort is a helper function to find a free random port, for instance to spawn Prometheus endpoint.
-func randomPort(t *testing.T) int {
-	random, err := net.Listen("tcp", "127.0.0.1:0")
-	require.NoError(t, err)
-	_ = random.Close()
-	tcpAddr, valid := random.Addr().(*net.TCPAddr)
-	require.True(t, valid)
-	return tcpAddr.Port
-}

enterprise/cli/proxyserver_test.go

@@ -63,7 +63,7 @@ func Test_Headers(t *testing.T) {
 func TestWorkspaceProxy_Server_PrometheusEnabled(t *testing.T) {
 	t.Parallel()
 
-	prometheusPort := randomPort(t)
+	prometheusPort := testutil.RandomPort(t)
 
 	var wg sync.WaitGroup
 	wg.Add(1)
@@ -96,7 +96,7 @@ func TestWorkspaceProxy_Server_PrometheusEnabled(t *testing.T) {
 		"--primary-access-url", srv.URL,
 		"--proxy-session-token", "test-token",
 		"--access-url", "http://foobar:3001",
-		"--http-address", fmt.Sprintf("127.0.0.1:%d", randomPort(t)),
+		"--http-address", fmt.Sprintf("127.0.0.1:%d", testutil.RandomPort(t)),
 		"--prometheus-enable",
 		"--prometheus-address", fmt.Sprintf("127.0.0.1:%d", prometheusPort),
 	)

enterprise/cli/server_test.go

@@ -22,7 +22,7 @@ func TestServer(t *testing.T) {
 	var root cli.RootCmd
 	cmd, err := root.Command(root.EnterpriseSubcommands())
 	require.NoError(t, err)
-	port := randomPort(t)
+	port := testutil.RandomPort(t)
 	inv, _ := clitest.NewWithCommand(t, cmd,
 		"server",
 		"--in-memory",