diff --git a/.travis.yml b/.travis.yml
index 25342a9..e5fa142 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ go:
   - tip
 
 install:
-  - go get -t -v . ./pry
+  - go get -t -v . ./pry ./generate ./playground/server
 
 before_install:
   - if ! go get github.com/golang/tools/cmd/cover; then go get golang.org/x/tools/cmd/cover; fi
@@ -20,5 +20,6 @@ script:
   - go test -v -race -coverprofile=pry.coverprofile ./pry
   - go test -v -race -coverprofile=generate.coverprofile ./generate
   - go test -v -race -coverprofile=main.coverprofile
+  - go test -v -race -coverprofile=server.coverprofile ./playground/server
   - $HOME/gopath/bin/gover
   - $HOME/gopath/bin/goveralls -service=travis-ci -coverprofile=gover.coverprofile
diff --git a/playground/server/server.go b/playground/server/server.go
index 5bc7282..265dd4e 100644
--- a/playground/server/server.go
+++ b/playground/server/server.go
@@ -19,6 +19,8 @@ import (
 	"github.com/pkg/errors"
 )
 
+const bundlesDir = "bundles"
+
 var bind = flag.String("bind", ":8080", "address to bind to")
 
 func main() {
@@ -48,8 +50,8 @@ func normalizePackages(packages string) []string {
 func generateBundle(w http.ResponseWriter, r *http.Request, packages string) (retErr error) {
 	pkgs := normalizePackages(packages)
 	hash := pkgHash(pkgs)
-	path := filepath.Join("bundles", hash+".wasm")
-	goPath := filepath.Join("bundles", hash+".go")
+	path := filepath.Join(bundlesDir, hash+".wasm")
+	goPath := filepath.Join(bundlesDir, hash+".go")
 	_, err := os.Stat(path)
 	if err == nil {
 		http.ServeFile(w, r, path)
diff --git a/playground/server/server11_test.go b/playground/server/server11_test.go
new file mode 100644
index 0000000..28ac0b3
--- /dev/null
+++ b/playground/server/server11_test.go
@@ -0,0 +1,40 @@
+// +build go1.11
+
+package main
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+)
+
+func TestGenerateBundle(t *testing.T) {
+	t.Parallel()
+
+	remove := func() {
+		if err := os.RemoveAll(bundlesDir); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	remove()
+
+	if err := os.MkdirAll(bundlesDir, 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	r, err := http.NewRequest(http.MethodGet, "/wasm/math,fmt", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	resp := httptest.NewRecorder()
+	if err := generateBundle(resp, r, "math,fmt"); err != nil {
+		t.Fatal(err)
+	}
+	if resp.Code != http.StatusOK {
+		t.Fatalf("expected StatusOK got %+v", resp.Code)
+	}
+
+	remove()
+}
diff --git a/playground/server/server_test.go b/playground/server/server_test.go
new file mode 100644
index 0000000..73c52ad
--- /dev/null
+++ b/playground/server/server_test.go
@@ -0,0 +1,35 @@
+package main
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestNormalizePackages(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		in   string
+		want []string
+	}{
+		{
+			"",
+			nil,
+		},
+		{
+			"foo, bar,github.com/d4l3k/go-pry ",
+			[]string{
+				"bar",
+				"foo",
+				"github.com/d4l3k/go-pry",
+			},
+		},
+	}
+
+	for i, c := range cases {
+		out := normalizePackages(c.in)
+		if !reflect.DeepEqual(out, c.want) {
+			t.Errorf("%d. normalizePackages(%q) = %+v; not %+v", i, c.in, out, c.want)
+		}
+	}
+}