dom

A pure Go implementation of a subset of the WHATWG DOM, backed by golang.org/x/net/html, with CSS selectors from andybalholm/cascadia.

Its main use is asserting on the HTML your handlers return, without a browser.

go get github.com/typelate/dom

func TestGreeting(t *testing.T) {
	res := httptest.NewRecorder()
	handler.ServeHTTP(res, httptest.NewRequest("GET", "/", nil))

	doc := domtest.ParseResponseDocument(t, res.Result())
	heading := doc.QuerySelector("h1")
	if heading == nil {
		t.Fatal("expected an h1")
	}
	if got := heading.TextContent(); got != "Hello" {
		t.Errorf("heading = %q, want %q", got, "Hello")
	}
}

To assert on a fragment rather than a whole page, parse it in the context of the element it will land in — the parent decides how the markup is interpreted:

rows := domtest.ParseResponseDocumentFragment(t, res.Result(), atom.Tbody)

• An invalid CSS selector panics, because queries compile with cascadia.MustCompile.
• domtest helpers report failures with t.Error and return nil, which does not stop the test. Check the result before using it.
• Collections are not uniformly live: Children reflects later mutations, while GetElementsByTagName and GetElementsByClassName return a snapshot.