Address Copilot review: precise assertions, guarded type checks, fix comment

- visitor_lint_test.go: assert Target.Name and Target.Module separately
  to prevent false positives
- visitor_widgets_test.go: use guarded type assertion with len check
  instead of direct assertion that would panic
- mock_page_mutator.go: clarify doc comment that ContainerType defaults
  to ContainerPage, not zero value

Author: retran

mdl/backend/mock/mock_page_mutator.go

@@ -12,7 +12,8 @@ var _ backend.PageMutator = (*MockPageMutator)(nil)
 
 // MockPageMutator implements backend.PageMutator. Every interface method is
 // backed by a public function field. If the field is nil the method returns
-// zero values / nil error (never panics).
+// nil error (never panics). ContainerType defaults to ContainerPage when unset;
+// all other methods return zero values.
 type MockPageMutator struct {
 	ContainerTypeFunc        func() backend.ContainerKind
 	SetWidgetPropertyFunc    func(widgetRef string, prop string, value any) error

mdl/visitor/visitor_lint_test.go

@@ -45,9 +45,11 @@ func TestLint_ModuleOnly(t *testing.T) {
 	if stmt.Target == nil {
 		t.Fatal("Expected non-nil Target")
 	}
-	// For "LINT MyModule.*", qualifiedName is just "MyModule" (no module prefix)
-	if stmt.Target.Name != "MyModule" && stmt.Target.Module != "MyModule" {
-		t.Errorf("Target mismatch: got Module=%q Name=%q", stmt.Target.Module, stmt.Target.Name)
+	if stmt.Target.Name != "MyModule" {
+		t.Errorf("Expected Target.Name %q, got %q", "MyModule", stmt.Target.Name)
+	}
+	if stmt.Target.Module != "" {
+		t.Errorf("Expected Target.Module %q, got %q", "", stmt.Target.Module)
 	}
 }
 

mdl/visitor/visitor_widgets_test.go

@@ -44,7 +44,13 @@ func TestUpdateWidgets_DryRun(t *testing.T) {
 		}
 		return
 	}
-	stmt := prog.Statements[0].(*ast.UpdateWidgetsStmt)
+	if len(prog.Statements) == 0 {
+		t.Fatal("Expected at least one statement")
+	}
+	stmt, ok := prog.Statements[0].(*ast.UpdateWidgetsStmt)
+	if !ok {
+		t.Fatalf("Expected *ast.UpdateWidgetsStmt, got %T", prog.Statements[0])
+	}
 	if !stmt.DryRun {
 		t.Error("Expected DryRun true")
 	}