stihl stihl - 1 year ago 151
HTTP Question

Unittest with template golang

I have a very simple http handler serving the template about.html

func AboutPage(w http.ResponseWriter, r *http.Request, ps httprouter.Params) {
template, err := template.ParseFiles("templates/about.html")

if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)

template.Execute(w, nil)

It works fine, but when i want to run this unit test:

func getRequest(t testing.TB, url string) *http.Request {
req, err := http.NewRequest("GET", url, nil)
if err != nil {
return req

func TestAboutPage(t *testing.T) {
r := getRequest(t, "/about")

rw := httptest.NewRecorder()

AboutPage(rw, r, httprouter.Params{})


The program crashes with this:

go test
--- FAIL: TestAboutPage (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x20 pc=0x41123b4]

goroutine 19 [running]:
panic(0x4417520, 0xc42000c0b0)
/usr/local/go/src/runtime/panic.go:500 +0x1a1
/usr/local/go/src/testing/testing.go:579 +0x25d
panic(0x4417520, 0xc42000c0b0)
/usr/local/go/src/runtime/panic.go:458 +0x243
html/template.(*Template).escape(0x0, 0x0, 0x0)
/usr/local/go/src/html/template/template.go:79 +0x44
html/template.(*Template).Execute(0x0, 0x52683b0, 0xc42007a7c0, 0x0, 0x0, 0xc420077290, 0x1)
/usr/local/go/src/html/template/template.go:101 +0x2f, 0xc42007a7c0, 0xc4200ee0f0, 0xc42004bf38, 0x0, 0x0)
/Users/dbubel/gowork/src/ +0xbd
/Users/dbubel/gowork/src/ +0x15c
testing.tRunner(0xc42009e180, 0x449b320)
/usr/local/go/src/testing/testing.go:610 +0x81
created by testing.(*T).Run
/usr/local/go/src/testing/testing.go:646 +0x2ec
exit status 2
FAIL 0.012s

If i replace template.execute() with a simple Fprintf(w, "foo") the test runs fine. So how is unittesting done with a template?

Answer Source

Ok i think i figured it out, i'm using

_ ""

as an import. I ran go install in that directory and now it runs...

Recommended from our users: Dynamic Network Monitoring from WhatsUp Gold from IPSwitch. Free Download