update test case to support custom error page

Signed-off-by: Stephen Glass <stephen@stephen.glass>

plugins/techdocs/src/reader/components/TechDocsReaderPageContent/TechDocsReaderPageContent.test.tsx

@@ -126,20 +126,19 @@ describe('<TechDocsReaderPageContent />', () => {
     useTechDocsReaderDom.mockReturnValue(document.createElement('html'));
     useReaderState.mockReturnValue({ state: 'cached' });
 
-    const rendered = await renderInTestApp(
-      <Wrapper>
-        <TechDocsReaderPageContent withSearch={false} />
-      </Wrapper>,
-    );
+    await expect(
+      renderInTestApp(
+        <Wrapper>
+          <TechDocsReaderPageContent withSearch={false} />
+        </Wrapper>,
+      ),
+    ).rejects.toThrow('Reached NotFound Page');
 
-    await waitFor(() => {
-      expect(
-        rendered.queryByTestId('techdocs-native-shadowroot'),
-      ).not.toBeInTheDocument();
-      expect(
-        rendered.getByText('ERROR 404: PAGE NOT FOUND'),
-      ).toBeInTheDocument();
-    });
+    // Check the global document for the absence of the shadow root
+    const shadowRoot = document.querySelector(
+      '[data-testid="techdocs-native-shadowroot"]',
+    );
+    expect(shadowRoot).not.toBeInTheDocument();
   });
 
   it('should render 404 if there is no dom and reader state is not found', async () => {