@@ 3,6 3,7 @@
 package builder
 
 import (
+	"compress/gzip"
 	"crypto/tls"
 	"errors"
 	"fmt"


@@ 191,8 192,12 @@
 	}
 
 	if conf := s.Root.Gzip; conf != nil {
+		level := conf.CompressionLevel
+		if level == 0 {
+			level = gzip.DefaultCompression
+		}
 		gzh, err := gziphandler.GzipHandlerWithOpts(
-			gziphandler.CompressionLevel(conf.CompressionLevel),
+			gziphandler.CompressionLevel(level),
 			gziphandler.ContentTypes(conf.ContentTypes),
 			gziphandler.MinSize(conf.MinSize),
 		)

@@ 3,6 3,7 @@
 import (
 	"crypto/tls"
 	"fmt"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"


@@ 10,6 11,7 @@
 	"testing"
 
 	"git.sr.ht/~mna/kick"
+	"github.com/unrolled/secure"
 )
 
 func TestTLS_Intermediate(t *testing.T) {


@@ 265,3 267,61 @@
 		})
 	}
 }
+
+func TestHandler_Valid(t *testing.T) {
+	s := &kick.Server{
+		Root: &kick.Root{
+			MethodNotAllowedHandler: statusHandler(405),
+			NotFoundHandler:         statusHandler(404),
+			PanicRecoveryFunc: func(w http.ResponseWriter, r *http.Request, v interface{}) {
+				w.WriteHeader(500)
+			},
+			TrustProxyHeaders:   true,
+			AllowMethodOverride: true,
+			RequestIDHeader:     "X-Request-Id",
+			SecurityHeaders: &secure.Options{
+				FrameDeny: true,
+			},
+			Gzip: &kick.GzipConfig{
+				ContentTypes: []string{"application/xml"},
+			},
+		},
+		Routes: []*kick.Route{
+			{
+				Method:  "GET",
+				Path:    "/",
+				Handler: statusHandler(200),
+			},
+			{
+				Method: "POST",
+				Path:   "/panic",
+				Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					panic(io.EOF)
+				}),
+			},
+		},
+	}
+
+	h, err := Handler(s)
+	if err != nil {
+		t.Fatalf("want no error, got %s", err)
+	}
+
+	cases := []struct {
+		req  string // formatted as "METHOD /path/... body"
+		reqh string // formatted as "Name:Value Name:Value"
+		code int
+		resh string // formatted as "Name:Value", * means any value
+	}{
+		{
+			req:  "GET /",
+			code: 200,
+			resh: "X-Request-Id:*",
+		},
+	}
+	for _, c := range cases {
+		t.Run(fmt.Sprintf("%s %s", c.req, c.reqh), func(t *testing.T) {
+			_ = h
+		})
+	}
+}