feat: show no-WFB kiosk fallback only while video absent (#2)

internal/display/fallback_test.go

@@ -0,0 +1,57 @@
+package display
+
+import "testing"
+
+const wantFallbackText = "Brak połączenia WFB"
+
+func TestFallbackTemplateShowsExactTextWhileVideoAbsent(t *testing.T) {
+	canvas := &fakeCanvas{width: 800, height: 600}
+	presence := NewVideoPresence()
+
+	NewFallbackTemplate(presence, wantFallbackText).Draw(canvas)
+
+	clears, flushes := canvas.drawCounts()
+	if clears != 1 || flushes != 1 {
+		t.Fatalf("clears=%d flushes=%d want 1 and 1", clears, flushes)
+	}
+	lines := canvas.lines()
+	if len(lines) != 1 || lines[0] != wantFallbackText {
+		t.Fatalf("lines=%q want [%q]", lines, wantFallbackText)
+	}
+}
+
+func TestFallbackTemplateDisappearsWhileVideoPresent(t *testing.T) {
+	canvas := &fakeCanvas{width: 800, height: 600}
+	presence := NewVideoPresence()
+	presence.SetActive(true)
+
+	NewFallbackTemplate(presence, wantFallbackText).Draw(canvas)
+
+	clears, flushes := canvas.drawCounts()
+	if clears != 1 || flushes != 1 {
+		t.Fatalf("clears=%d flushes=%d want 1 and 1", clears, flushes)
+	}
+	if lines := canvas.lines(); len(lines) != 0 {
+		t.Fatalf("video has priority: fallback lines %q must disappear", lines)
+	}
+}
+
+func TestFallbackTemplateReturnsWhenVideoEnds(t *testing.T) {
+	canvas := &fakeCanvas{width: 800, height: 600}
+	presence := NewVideoPresence()
+	presence.SetActive(true)
+	template := NewFallbackTemplate(presence, wantFallbackText)
+
+	template.Draw(canvas)
+	if lines := canvas.lines(); len(lines) != 0 {
+		t.Fatalf("lines=%q must stay empty while video is present", lines)
+	}
+
+	presence.SetActive(false)
+	template.Draw(canvas)
+
+	lines := canvas.lines()
+	if len(lines) != 1 || lines[0] != wantFallbackText {
+		t.Fatalf("lines=%q want fallback [%q] after video end", lines, wantFallbackText)
+	}
+}