diff --git a/.travis.yml b/.travis.yml
index 5e663d4..7b87d6a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,6 @@
 sudo: false
 language: go
+script: go test -short -v ./...
 go:
-- 1.6
+- 1.8.x
 - 1.x
diff --git a/integration_test.go b/integration_test.go
new file mode 100644
index 0000000..44736d6
--- /dev/null
+++ b/integration_test.go
@@ -0,0 +1,311 @@
+// Copyright 2018 Google Inc. 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 main
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestIntegration(t *testing.T) {
+	if testing.Short() {
+		t.Skip("Skipping due to -test.short")
+	}
+	goExe, err := exec.LookPath("go")
+	if err != nil {
+		t.Skipf("Could not find go tool: %v", err)
+	}
+
+	var gitURLArgv []string
+	var hgURLArgv []string
+	if gitExe, err := exec.LookPath("git"); err != nil {
+		t.Logf("Could not find git: %v", err)
+	} else {
+		gitURLArgv = []string{gitExe, "remote", "get-url", "origin"}
+	}
+	if hgExe, err := exec.LookPath("hg"); err != nil {
+		t.Logf("Could not find hg: %v", err)
+	} else {
+		hgURLArgv = []string{hgExe, "paths", "default"}
+	}
+	if gitURLArgv == nil && hgURLArgv == nil {
+		t.Skip("Could not find any VCS; skipping")
+	}
+	tests := []struct {
+		name       string
+		config     string
+		importPath string
+		getURLArgv []string
+		wantURL    string
+	}{
+		{
+			name: "GitHub",
+			config: "host: example.com\n" +
+				"paths:\n" +
+				"  /portmidi:\n" +
+				"    repo: https://github.com/rakyll/portmidi\n",
+			importPath: "example.com/portmidi",
+			getURLArgv: gitURLArgv,
+			wantURL:    "https://github.com/rakyll/portmidi",
+		},
+		{
+			name: "Bitbucket Mercurial",
+			config: "host: example.com\n" +
+				"paths:\n" +
+				"  /gopdf:\n" +
+				"    repo: https://bitbucket.org/zombiezen/gopdf\n" +
+				"    vcs: hg\n",
+			importPath: "example.com/gopdf/pdf",
+			getURLArgv: hgURLArgv,
+			wantURL:    "https://bitbucket.org/zombiezen/gopdf",
+		},
+		{
+			name: "Bitbucket Git",
+			config: "host: example.com\n" +
+				"paths:\n" +
+				"  /cardcpx:\n" +
+				"    repo: https://bitbucket.org/zombiezen/cardcpx.git\n" +
+				"    vcs: git\n",
+			importPath: "example.com/cardcpx/natsort",
+			getURLArgv: gitURLArgv,
+			wantURL:    "https://bitbucket.org/zombiezen/cardcpx.git",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if test.getURLArgv == nil {
+				t.Skip("VCS tool not installed; skipping")
+			}
+			h, err := newHandler([]byte(test.config))
+			if err != nil {
+				t.Fatal(err)
+			}
+			tempRoot, err := ioutil.TempDir("", "govanityurls_integration")
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer func() {
+				if err := os.RemoveAll(tempRoot); err != nil {
+					t.Error(err)
+				}
+			}()
+			tempDir := filepath.Join(tempRoot, "tmp")
+			if err := os.Mkdir(tempDir, 0777); err != nil {
+				t.Fatal(err)
+			}
+			cacheDir := filepath.Join(tempRoot, "cache")
+			if err := os.Mkdir(cacheDir, 0777); err != nil {
+				t.Fatal(err)
+			}
+			gopathDir := filepath.Join(tempRoot, "gopath")
+			if err := os.Mkdir(gopathDir, 0777); err != nil {
+				t.Fatal(err)
+			}
+			srv := httptest.NewServer(&proxy{
+				rt:      http.DefaultTransport,
+				host:    "example.com",
+				handler: h,
+			})
+			defer srv.Close()
+			goCmd := exec.Command(goExe, "get", "-insecure", "-d", test.importPath)
+			goCmd.Env = appendEnv(os.Environ(),
+				"GOPATH="+gopathDir,
+				"HTTP_PROXY="+srv.URL,
+				"TMPDIR="+tempDir,
+				// Go 1.10+ environment variables:
+				"GOCACHE="+cacheDir,
+				"GOTMPDIR="+tempDir)
+			getOutput, err := goCmd.CombinedOutput()
+			if err != nil {
+				t.Fatalf("go get failed. log:\n%s", getOutput)
+			}
+
+			vcsStderr := new(bytes.Buffer)
+			vcsStderrLimiter := &limitedWriter{w: vcsStderr, n: 2048}
+			vcsCmd := exec.Cmd{
+				Path: test.getURLArgv[0],
+				Args: test.getURLArgv,
+				Env: appendEnv(os.Environ(),
+					"HOME="+tempRoot,
+					"TMPDIR="+tempDir,
+					"XDG_CONFIG_HOME="+filepath.Join(tempRoot, ".config")), // intentionally does not exist
+				Dir:    filepath.Join(gopathDir, "src", filepath.FromSlash(test.importPath)),
+				Stderr: vcsStderrLimiter,
+			}
+			got, err := vcsCmd.Output()
+			if err != nil {
+				format := "%s failed. log:\n%s"
+				if vcsStderrLimiter.truncated {
+					format += "<truncated>"
+				}
+				t.Fatalf(format, strings.Join(test.getURLArgv, " "), vcsStderr.Bytes())
+			}
+			if want := []byte(test.wantURL + "\n"); !bytes.Equal(got, want) {
+				t.Errorf("%s = %q; want %q", strings.Join(test.getURLArgv, " "), got, want)
+			}
+		})
+	}
+}
+
+// proxy is an HTTP proxy that forwards requests to a certain host to
+// another handler.
+type proxy struct {
+	rt http.RoundTripper
+
+	host    string
+	handler http.Handler
+}
+
+func (p *proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	host, _, err := net.SplitHostPort(r.Host)
+	if err != nil {
+		// Just "host", without port.
+		host = r.URL.Host
+	}
+	switch r.Method {
+	case http.MethodGet, http.MethodHead:
+		if host == p.host {
+			p.handler.ServeHTTP(w, r)
+			return
+		}
+		res, err := p.rt.RoundTrip(r)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadGateway)
+			return
+		}
+		defer res.Body.Close()
+		for k, v := range res.Header {
+			w.Header()[k] = append([]string(nil), v...)
+		}
+		w.WriteHeader(res.StatusCode)
+		io.Copy(w, res.Body)
+	case http.MethodConnect:
+		if host == p.host {
+			w.Header().Set("Allow", "GET, HEAD")
+			http.Error(w, "test proxy only allows GET and HEAD to "+r.Host, http.StatusMethodNotAllowed)
+			return
+		}
+		p.connect(w, r)
+	default:
+		w.Header().Set("Allow", "GET, HEAD, CONNECT")
+		http.Error(w, "test proxy only allows GET, HEAD, and CONNECT", http.StatusMethodNotAllowed)
+	}
+}
+
+func (p *proxy) connect(w http.ResponseWriter, r *http.Request) {
+	c1, err := new(net.Dialer).DialContext(r.Context(), "tcp", r.Host)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+		return
+	}
+	w.WriteHeader(http.StatusOK)
+	hi, ok := w.(http.Hijacker)
+	if !ok {
+		http.Error(w, "could convert HTTP connection to TCP", http.StatusInternalServerError)
+		return
+	}
+	c2, brw, err := hi.Hijack()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	c2.SetDeadline(time.Time{})
+	var wg sync.WaitGroup
+	wg.Add(2)
+	go func() {
+		defer wg.Done()
+		buf, _ := brw.Reader.Peek(brw.Reader.Buffered())
+		c1.Write(buf)
+		io.Copy(c1, c2)
+	}()
+	go func() {
+		defer wg.Done()
+		io.Copy(c2, c1)
+	}()
+	wg.Wait()
+	c1.Close()
+	c2.Close()
+}
+
+// appendEnv returns a new environment variable list that overrides
+// environment variables from base.
+//
+// Before Go 1.9, os/exec.Cmd.Env would not be deduplicated.
+func appendEnv(base []string, add ...string) []string {
+	out := make([]string, 0, len(base)+len(add))
+	saw := make(map[string]int)
+	insert := func(kv string) {
+		eq := strings.IndexByte(kv, '=')
+		if eq < 0 {
+			out = append(out, kv)
+			return
+		}
+		k := kv[:eq]
+		if dupIdx, isDup := saw[k]; isDup {
+			out[dupIdx] = kv
+			return
+		}
+		saw[k] = len(out)
+		out = append(out, kv)
+	}
+	for _, kv := range base {
+		insert(kv)
+	}
+	for _, kv := range add {
+		insert(kv)
+	}
+	return out
+}
+
+type limitedWriter struct {
+	w         io.Writer
+	n         int64
+	truncated bool
+}
+
+func (l *limitedWriter) Write(p []byte) (n int, err error) {
+	if len(p) == 0 {
+		return 0, nil
+	}
+	if l.n <= 0 {
+		l.truncated = true
+		return 0, errors.New("reached write limit")
+	}
+	if int64(len(p)) > l.n {
+		l.truncated = true
+		n, err = l.w.Write(p[:l.n])
+		l.n -= int64(n)
+		if err != nil {
+			return n, err
+		}
+		return n, errors.New("reached write limit")
+	}
+	n, err = l.w.Write(p)
+	l.n -= int64(n)
+	return n, err
+}