Tweak tests to check unsetting works.

Author: rodrigogiraoserrao

tests/test_tabbed_content.py

@@ -108,9 +108,33 @@ def compose(self) -> ComposeResult:
         with pytest.raises(ValueError):
             tabbed_content.active = "X"
 
-        # Check fail with empty tab
-        with pytest.raises(ValueError):
-            tabbed_content.active = ""
+
+async def test_unsetting_tabbed_content_active():
+    """Check that setting `TabbedContent.active = ""` unsets active tab."""
+
+    messages = []
+
+    class TabbedApp(App[None]):
+        def compose(self) -> ComposeResult:
+            with TabbedContent(initial="bar"):
+                with TabPane("foo", id="foo"):
+                    yield Label("Foo", id="foo-label")
+                with TabPane("bar", id="bar"):
+                    yield Label("Bar", id="bar-label")
+                with TabPane("baz", id="baz"):
+                    yield Label("Baz", id="baz-label")
+
+        def on_tabbed_content_cleared(self, event: TabbedContent.Cleared) -> None:
+            messages.append(event)
+
+    app = TabbedApp()
+    async with app.run_test() as pilot:
+        tabbed_content = app.query_one(TabbedContent)
+        assert bool(tabbed_content.active)
+        tabbed_content.active = ""
+        await pilot.pause()
+        assert len(messages) == 1
+        assert isinstance(messages[0], TabbedContent.Cleared)
 
 
 async def test_tabbed_content_initial():

tests/test_tabs.py

@@ -316,15 +316,8 @@ def compose(self) -> ComposeResult:
         assert tabs.active_tab.id == "tab-2"
         assert tabs.active == tabs.active_tab.id
 
-        # TODO: This one is questionable. It seems Tabs has been designed so
-        # that you can set the active tab to an empty string, and it remains
-        # so, and just removes the underline; no other changes. So active
-        # will be an empty string while active_tab will be a tab. This feels
-        # like an oversight. Need to investigate and possibly modify this
-        # behaviour unless there's a good reason for this.
         tabs.active = ""
-        assert tabs.active_tab is not None
-        assert tabs.active_tab.id == "tab-2"
+        assert tabs.active_tab is None
 
 
 async def test_navigate_tabs_with_keyboard():