Add tests for clicking on a link when markdown is from a string

Co-authored-by: Timothée Mazzucotelli <pawamoy@pm.me>

tests/test_markdownviewer.py

@@ -7,7 +7,7 @@ from textual.geometry import Offset
 from textual.widgets import Markdown, MarkdownViewer
 
 
-class MarkdownViewerApp(App[None]):
+class MarkdownFileViewerApp(App[None]):
     def compose(self) -> ComposeResult:
         yield MarkdownViewer()
 
@@ -17,9 +17,29 @@ class MarkdownViewerApp(App[None]):
 
 
 @pytest.mark.parametrize("link", [0, 1, 2])
-async def test_markdown_viewer_anchor_link(link: int) -> None:
+async def test_markdown_file_viewer_anchor_link(link: int) -> None:
     """Test https://github.com/Textualize/textual/issues/3094"""
-    async with MarkdownViewerApp().run_test() as pilot:
+    async with MarkdownFileViewerApp().run_test() as pilot:
+        # There's not really anything to test *for* here, but the lack of an
+        # exception is the win (before the fix this is testing it would have
+        # been FileNotFoundError).
+        await pilot.click(Markdown, Offset(2, link))
+
+
+class MarkdownStringViewerApp(App[None]):
+    def compose(self) -> ComposeResult:
+        yield MarkdownViewer(Path(__file__).with_suffix(".md").read_text())
+
+    async def on_mount(self) -> None:
+        self.query_one(MarkdownViewer).show_table_of_contents = False
+
+
+@pytest.mark.parametrize("link", [0, 1, 2])
+async def test_markdown_string_viewer_anchor_link(link: int) -> None:
+    """Test https://github.com/Textualize/textual/issues/3094
+
+    Also https://github.com/Textualize/textual/pull/3244#issuecomment-1710278718."""
+    async with MarkdownStringViewerApp().run_test() as pilot:
         # There's not really anything to test *for* here, but the lack of an
         # exception is the win (before the fix this is testing it would have
         # been FileNotFoundError).