fix: review fixes

Author: sergeyshmakov

src/decorators/rootSelectors.ts

@@ -12,12 +12,24 @@ type PageFirstArgs<TClass extends AnyConstructor> =
 		? [page: Page, ...rest: TRest]
 		: never;
 
+function isLocatorLike(
+	value: object,
+): value is Pick<Locator, "locator" | "page"> {
+	return (
+		"locator" in value &&
+		typeof (value as { locator?: unknown }).locator === "function" &&
+		"page" in value &&
+		typeof (value as { page?: unknown }).page === "function"
+	);
+}
+
 function resolvePage(value: unknown, className: string): Page {
 	if (
 		typeof value === "object" &&
 		value !== null &&
 		"locator" in value &&
-		typeof (value as { locator?: unknown }).locator === "function"
+		typeof (value as { locator?: unknown }).locator === "function" &&
+		!isLocatorLike(value)
 	) {
 		return value as Page;
 	}

src/tests/decorators/rootSelectors.spec.ts

@@ -72,6 +72,20 @@ describe("RootSelectorBy (via exported wrappers)", () => {
 		);
 	});
 
+	it("rejects Locator values passed as the first constructor arg", () => {
+		@RootSelector()
+		class ExternalRootPage {
+			constructor(readonly page: Page) {}
+		}
+
+		const locator = createMockLocator(mockPage);
+
+		expect(() => new ExternalRootPage(locator as unknown as Page)).toThrow(
+			/ExternalRootPage.*must receive Playwright Page as the first constructor argument/,
+		);
+		expect(locator.locator).not.toHaveBeenCalledWith("body");
+	});
+
 	it("RootSelector(id) uses p.getByTestId(id)", () => {
 		@RootSelector("myId")
 		class TestPage extends RootPageObject {}