test(13-03): add failing tests for Select and FormField components (RED)

- TestSelect_RendersControl: expects ui-select-control in output
- TestSelect_HasInlineScript: expects __uiSelectInitAll in script block
- TestSelect_HasHtmxListener: expects htmx:afterSwap re-init listener
- TestFormField_RendersLabel: expects ui-form-field and ui-form-label
- TestFormField_RendersError: expects ui-form-error when Error is set
- TestFormField_NoErrorWhenEmpty: expects no ui-form-error when Error is empty

backend/internal/web/ui/ui_test.go

@@ -280,3 +280,69 @@ func TestTextarea_ExplicitRows(t *testing.T) {
 		t.Errorf("expected rows=\"6\"; got: %s", out)
 	}
 }
+
+// Phase 13 Plan 03 — Select and FormField component tests (TDD RED)
+
+func TestSelect_RendersControl(t *testing.T) {
+	out := render(t, context.Background(), Select(SelectProps{
+		Name:    "status",
+		Options: []SelectOption{{Value: "a", Label: "Alpha"}},
+	}))
+	if !strings.Contains(out, "ui-select-control") {
+		t.Errorf("expected ui-select-control in output; got: %s", out)
+	}
+}
+
+func TestSelect_HasInlineScript(t *testing.T) {
+	out := render(t, context.Background(), Select(SelectProps{
+		Name:    "status",
+		Options: []SelectOption{{Value: "a", Label: "Alpha"}},
+	}))
+	if !strings.Contains(out, "__uiSelectInitAll") {
+		t.Errorf("expected __uiSelectInitAll in output (inline JS); got: %s", out)
+	}
+}
+
+func TestSelect_HasHtmxListener(t *testing.T) {
+	out := render(t, context.Background(), Select(SelectProps{
+		Name:    "status",
+		Options: []SelectOption{{Value: "a", Label: "Alpha"}},
+	}))
+	if !strings.Contains(out, "htmx:afterSwap") {
+		t.Errorf("expected htmx:afterSwap in output (re-init listener); got: %s", out)
+	}
+}
+
+func TestFormField_RendersLabel(t *testing.T) {
+	out := render(t, context.Background(), FormField(FormFieldProps{
+		Label: "Name",
+		For:   "name-input",
+	}))
+	for _, want := range []string{"ui-form-field", "ui-form-label"} {
+		if !strings.Contains(out, want) {
+			t.Errorf("expected %q in output; got: %s", want, out)
+		}
+	}
+}
+
+func TestFormField_RendersError(t *testing.T) {
+	out := render(t, context.Background(), FormField(FormFieldProps{
+		Label: "Name",
+		For:   "name-input",
+		Error: "This field is required",
+	}))
+	if !strings.Contains(out, "ui-form-error") {
+		t.Errorf("expected ui-form-error in output when Error is set; got: %s", out)
+	}
+}
+
+func TestFormField_NoErrorWhenEmpty(t *testing.T) {
+	out := render(t, context.Background(), FormField(FormFieldProps{
+		Label: "Name",
+		For:   "name-input",
+		Error: "",
+	}))
+	if strings.Contains(out, "ui-form-error") {
+		t.Errorf("expected NO ui-form-error in output when Error is empty; got: %s", out)
+	}
+}