Added tests for proxy

sumdb/proxy.go

@@ -57,8 +57,8 @@ func NewProxy(opts ProxyOpts) *httputil.ReverseProxy {
 		Rewrite: func(r *httputil.ProxyRequest) {
 			r.SetURL(upstream)
 			inPath := strings.TrimPrefix(r.In.URL.Path, prefix)
+			klog.V(2).Infof("Request for %s", inPath)
 
-			klog.V(2).Infof("Request for %s", r.In.URL.Path)
 			if inPath == "/checkpoint" {
 				r.Out.URL.Path = "/latest"
 			} else if strings.HasPrefix(inPath, tlogEntriesPrefix) {

sumdb/proxy_test.go

@@ -0,0 +1,147 @@
+// Copyright 2025 Google LLC. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package sumdb
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"testing"
+)
+
+func TestRewrite(t *testing.T) {
+	testCases := []struct {
+		desc       string
+		pathPrefix string
+		inPath     string
+		outPath    string
+	}{
+		{
+			desc:       "checkpoint no prefix",
+			pathPrefix: "",
+			inPath:     "/checkpoint",
+			outPath:    "/latest",
+		}, {
+			desc:       "checkpoint with prefix",
+			pathPrefix: "/customprefix",
+			inPath:     "/customprefix/checkpoint",
+			outPath:    "/latest",
+		}, {
+			desc:       "entries no prefix",
+			pathPrefix: "",
+			inPath:     "/tile/entries/000",
+			outPath:    "/tile/8/data/000",
+		}, {
+			desc:       "entries with prefix",
+			pathPrefix: "/customprefix",
+			inPath:     "/customprefix/tile/entries/000",
+			outPath:    "/tile/8/data/000",
+		}, {
+			desc:       "internal tile no prefix",
+			pathPrefix: "",
+			inPath:     "/tile/0/000",
+			outPath:    "/tile/8/0/000",
+		}, {
+			desc:       "internal tile with prefix",
+			pathPrefix: "/customprefix",
+			inPath:     "/customprefix/tile/0/000",
+			outPath:    "/tile/8/0/000",
+		},
+	}
+	for _, tC := range testCases {
+		t.Run(tC.desc, func(t *testing.T) {
+			proxy := NewProxy(ProxyOpts{PathPrefix: tC.pathPrefix})
+			req := &httputil.ProxyRequest{
+				In: &http.Request{
+					URL: mustParseURL(t, fmt.Sprintf("http://example.com%s", tC.inPath)),
+				},
+			}
+			out := *req.In
+			req.Out = &out
+			proxy.Rewrite(req)
+
+			if got, want := req.Out.URL.Path, tC.outPath; got != want {
+				t.Errorf("expected path to be %s but was %s", want, got)
+			}
+		})
+	}
+}
+
+func TestModifyResponse(t *testing.T) {
+	testCases := []struct {
+		desc string
+		path string
+		body []byte
+		want []byte
+	}{
+		{
+			desc: "checkpoint not changed",
+			path: "/latest",
+			body: []byte("moose\n42\ndeadbeef"),
+			want: []byte("moose\n42\ndeadbeef"),
+		},
+		{
+			desc: "entries body modified",
+			path: "/tile/8/data/000",
+			body: []byte("foo\nfoo1\n\nmoose\nmoose1\n"),
+			want: append(append(append([]byte{0, 9}, []byte("foo\nfoo1\n")...), []byte{0, 13}...), []byte("moose\nmoose1\n")...),
+		},
+		{
+			desc: "internal tiles not modified",
+			path: "/tile/8/0/000",
+			body: []byte("foo\nfoo1\n\nmoose\nmoose1\n"),
+			want: []byte("foo\nfoo1\n\nmoose\nmoose1\n"),
+		},
+	}
+	for _, tC := range testCases {
+		t.Run(tC.desc, func(t *testing.T) {
+			proxy := NewProxy(ProxyOpts{})
+			resp := &http.Response{
+				Request: &http.Request{
+					URL: mustParseURL(t, fmt.Sprintf("http://example.com%s", tC.path)),
+				},
+				Header: http.Header{},
+			}
+			resp.Body = io.NopCloser(bytes.NewBuffer(tC.body))
+			if err := proxy.ModifyResponse(resp); err != nil {
+				t.Fatal(err)
+			}
+			if got, want := mustReadAll(t, resp.Body), tC.want; !bytes.Equal(got, want) {
+				t.Errorf("expected body %v but got %v", want, got)
+			}
+		})
+	}
+}
+
+func mustParseURL(t *testing.T, raw string) *url.URL {
+	t.Helper()
+	u, err := url.Parse(raw)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return u
+}
+
+func mustReadAll(t *testing.T, r io.Reader) []byte {
+	t.Helper()
+	bs, err := io.ReadAll(r)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return bs
+}