test(caddy): fix flaky tests on macOS

caddy/caddy_test.go

@@ -11,6 +11,7 @@ import (
 	"sync"
 	"sync/atomic"
 	"testing"
+	"time"
 
 	"github.com/caddyserver/caddy/v2"
 	"github.com/caddyserver/caddy/v2/caddytest"
@@ -19,6 +20,26 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
+// waitForServerReady polls the server with retries until it responds to HTTP requests.
+// This handles a race condition during Caddy config reload on macOS where SO_REUSEPORT
+// can briefly route connections to the old listener being shut down,
+// resulting in "connection reset by peer".
+func waitForServerReady(t *testing.T, url string) {
+	t.Helper()
+
+	client := &http.Client{Timeout: 1 * time.Second}
+	for range 10 {
+		resp, err := client.Get(url)
+		if err == nil {
+			require.NoError(t, resp.Body.Close())
+
+			return
+		}
+
+		time.Sleep(100 * time.Millisecond)
+	}
+}
+
 var testPort = "9080"
 
 func TestPHP(t *testing.T) {
@@ -406,6 +427,7 @@ func TestPHPServerDirective(t *testing.T) {
 		}
 		`, "caddyfile")
 
+	waitForServerReady(t, "http://localhost:"+testPort)
 	tester.AssertGetResponse("http://localhost:"+testPort, http.StatusOK, "I am by birth a Genevese (i not set)")
 	tester.AssertGetResponse("http://localhost:"+testPort+"/hello.txt", http.StatusOK, "Hello\n")
 	tester.AssertGetResponse("http://localhost:"+testPort+"/not-found.txt", http.StatusOK, "I am by birth a Genevese (i not set)")
@@ -431,6 +453,7 @@ func TestPHPServerDirectiveDisableFileServer(t *testing.T) {
 		}
 		`, "caddyfile")
 
+	waitForServerReady(t, "http://localhost:"+testPort)
 	tester.AssertGetResponse("http://localhost:"+testPort, http.StatusOK, "I am by birth a Genevese (i not set)")
 	tester.AssertGetResponse("http://localhost:"+testPort+"/not-found.txt", http.StatusOK, "I am by birth a Genevese (i not set)")
 }