Show each page's own title in the browser tab (closes #117)

parsePageTemplate parsed the page file before htmlheader.html. A later
definition of a template name replaces an earlier one (an empty one
never does), so htmlheader.html's {{block "title"}} replaced every
page's {{define "title"}} and every tab read "Webhooker". The page file
is now parsed last, into a set named after it, so it stays the entry
point.

A new test renders every page template and checks its title; the
"Webhooker" fallback is checked on htmlheader.html alone, since every
page declares a title.

Model: opus-5-5

internal/handlers/handlers.go

@@ -110,22 +110,25 @@ type Handlers struct {
 // parsePageTemplate parses a page-specific template set from the
 // embedded FS. Each page template is combined with the shared
 // base, htmlheader, navbar and notice templates, and with any further
-// files the page includes. The page file must be listed first so that
+// files the page includes. The set is named after the page file, so
-// its root action ({{template "base" .}}) becomes the template set's
+// the page's root action ({{template "base" .}}) is its entry point.
-// entry point.
+//
+// The page file is parsed last because a later definition of a name
+// replaces an earlier one: the page's {{define "title"}} must replace
+// the {{block "title"}} fallback in htmlheader.html.
 func parsePageTemplate(
 	pageFile string, included ...string,
 ) *template.Template {
 	files := append([]string{
-		pageFile,
 		"base.html",
 		"htmlheader.html",
 		"navbar.html",
 		"notice.html",
 	}, included...)
+	files = append(files, pageFile)
 
 	return template.Must(
-		template.ParseFS(templates.Templates, files...),
+		template.New(pageFile).ParseFS(templates.Templates, files...),
 	)
 }
 

internal/handlers/page_title_test.go

@@ -0,0 +1,107 @@
+package handlers_test
+
+import (
+	"html/template"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/handlers"
+	"sneak.berlin/go/webhooker/internal/session"
+	"sneak.berlin/go/webhooker/templates"
+)
+
+// TestEveryPageRendersItsOwnTitle renders each page template and checks
+// the browser tab title is the one the page declares, not the
+// "Webhooker" fallback in htmlheader.html. A page that fails to render
+// shows the error page's title instead, and fails here too.
+func TestEveryPageRendersItsOwnTitle(t *testing.T) {
+	t.Parallel()
+
+	var h *handlers.Handlers
+
+	var sess *session.Session
+
+	app := newTestApp(t, &h, &sess)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	// A pointer, as in the handlers: some pages call
+	// Webhook.RetentionLabel, a pointer method.
+	webhook := &database.Webhook{Name: "orders", RetentionDays: 14}
+	webhook.ID = testWebhookID
+
+	pages := []struct {
+		page  string
+		data  map[string]any
+		title string
+	}{
+		{"login.html", map[string]any{}, "Login - Webhooker"},
+		{"profile.html", map[string]any{}, "Profile - Webhooker"},
+		{"settings.html", map[string]any{}, "Settings - Webhooker"},
+		{"sources_list.html", map[string]any{}, "Webhooks - Webhooker"},
+		{"sources_new.html", map[string]any{}, "New Webhook - Webhooker"},
+		{
+			"source_detail.html",
+			map[string]any{dataKeyWebhook: webhook},
+			"orders - Webhooker",
+		},
+		{
+			"source_edit.html",
+			map[string]any{dataKeyWebhook: webhook},
+			"Edit orders - Webhooker",
+		},
+		{
+			"source_logs.html",
+			map[string]any{dataKeyWebhook: webhook, "TotalEvents": int64(0)},
+			"Full Event Log - orders - Webhooker",
+		},
+		{
+			"event_detail.html",
+			map[string]any{dataKeyWebhook: webhook},
+			"Event - orders - Webhooker",
+		},
+		{
+			"target_edit.html",
+			map[string]any{
+				dataKeyWebhook: webhook,
+				"Target":       map[string]any{"Name": "alerts", "Type": "slack"},
+			},
+			"Edit alerts - Webhooker",
+		},
+		{
+			"error.html",
+			map[string]any{"StatusText": http.StatusText(http.StatusNotFound)},
+			"Not Found - Webhooker",
+		},
+	}
+
+	for _, p := range pages {
+		body := renderPage(t, h, sess, p.page, p.data)
+
+		_, afterOpen, _ := strings.Cut(body, "<title>")
+		title, _, _ := strings.Cut(afterOpen, "</title>")
+
+		assert.Equal(t, p.title, title, p.page)
+	}
+}
+
+// TestTitleFallbackIsWebhooker checks the title htmlheader.html gives a
+// page that declares none. Every page declares one, so it is checked on
+// htmlheader.html alone.
+func TestTitleFallbackIsWebhooker(t *testing.T) {
+	t.Parallel()
+
+	header := template.Must(
+		template.ParseFS(templates.Templates, "htmlheader.html"),
+	)
+
+	var buf strings.Builder
+
+	require.NoError(t, header.ExecuteTemplate(&buf, "htmlheader", nil))
+	assert.Contains(t, buf.String(), "<title>Webhooker</title>")
+}