test: add login template text snapshot test

templates/snapshot_test.go

@@ -0,0 +1,42 @@
+package templates
+
+import (
+	"bytes"
+	"regexp"
+	"strings"
+	"testing"
+)
+
+func TestLoginTemplateTextSnapshot(t *testing.T) {
+	r, err := ProvideRenderer()
+	if err != nil {
+		t.Fatalf("ProvideRenderer: %v", err)
+	}
+
+	var buf bytes.Buffer
+	if err := r.ExecuteFragment(&buf, "login.gohtml", "content", map[string]any{}); err != nil {
+		t.Fatalf("ExecuteFragment: %v", err)
+	}
+
+	got := visibleTextSnapshot(buf.String())
+	const want = "Sign in to your account\nEmail address\nPassword\nSign In"
+	if got != want {
+		t.Fatalf("login text snapshot mismatch\n got: %q\nwant: %q", got, want)
+	}
+}
+
+func visibleTextSnapshot(html string) string {
+	tags := regexp.MustCompile(`<[^>]+>`)
+	spaces := regexp.MustCompile(`[ \t]+`)
+	blankLines := regexp.MustCompile(`\n+`)
+
+	text := tags.ReplaceAllString(html, "\n")
+	text = spaces.ReplaceAllString(text, " ")
+	lines := strings.Split(text, "\n")
+	for i, line := range lines {
+		lines[i] = strings.TrimSpace(line)
+	}
+	text = strings.Join(lines, "\n")
+	text = blankLines.ReplaceAllString(text, "\n")
+	return strings.TrimSpace(text)
+}