Feat #2: add Host Entry from selected

tests/test_app.py

@@ -19,6 +19,7 @@ from src.hosts.tui.custom_footer import CustomFooter
 from src.hosts.tui.backup_restore_modal import BackupRestoreModal
 from src.hosts.tui.filter_modal import FilterModal
 from src.hosts.tui.help_modal import HelpModal
+from src.hosts.tui.add_entry_modal import AddEntryModal
 from src.hosts.tui.privilege_prompt import (
     render_sudo_authentication_notice,
     sudo_authentication_screen,
@@ -97,6 +98,78 @@ async def test_filter_shortcut_does_not_stack_filter_modals():
         assert sum(isinstance(screen, FilterModal) for screen in app.screen_stack) == 1
 
 
+@pytest.mark.asyncio
+async def test_new_from_selected_prefills_the_highlighted_visible_entry():
+    """Shift+N snapshots the highlighted visible Host Entry into the Add form."""
+    app = app_with_filterable_entries()
+    source = app.hosts_file.entries[1]
+    source.hostnames = ["inactive.test", "alias.test"]
+    source.comment = "Copied comment"
+    source.is_active = False
+    app.edit_mode = True
+    app.sort_column = "hostname"
+
+    async with app.run_test(size=(120, 40)) as pilot:
+        app.table_handler.populate_entries_table()
+        app.table_handler.move_cursor_to_entry_index(1)
+        await pilot.pause()
+
+        await pilot.press("shift+n")
+        await pilot.pause()
+
+        assert isinstance(app.screen, AddEntryModal)
+        assert app.screen.query_one("#hostnames-input", Input).value == (
+            "inactive.test, alias.test"
+        )
+        assert app.screen.query_one("#ip-address-input", Input).value == "192.0.2.2"
+        assert app.screen.query_one("#comment-input", Input).value == "Copied comment"
+        assert not app.screen.query_one("#active-checkbox").value
+        assert "Based on: inactive.test" in str(
+            app.screen.query_one("#entry-source", Static).render()
+        )
+        assert app.focused is app.screen.query_one("#hostnames-input", Input)
+
+    assert source.hostnames == ["inactive.test", "alias.test"]
+    assert source.comment == "Copied comment"
+    assert not source.is_active
+
+
+@pytest.mark.asyncio
+async def test_new_from_selected_requires_a_visible_host_entry():
+    """Shift+N does not reuse a stale selection when filters hide every entry."""
+    app = app_with_filterable_entries()
+    app.edit_mode = True
+    app.current_filter_options.search_term = "not-a-match"
+
+    async with app.run_test(size=(120, 40)) as pilot:
+        app.table_handler.populate_entries_table()
+        await pilot.press("shift+n")
+        await pilot.pause()
+
+        assert not isinstance(app.screen, AddEntryModal)
+        assert "No Host Entry selected; use n to add a blank Host Entry." in str(
+            app.query_one("#message-rail", Static).render()
+        )
+
+
+@pytest.mark.asyncio
+async def test_new_from_selected_is_available_at_the_minimum_viewport():
+    """Shift+N keeps the selected-entry add workflow reachable at 100×30."""
+    app = app_with_filterable_entries()
+    app.edit_mode = True
+
+    async with app.run_test(size=(100, 30)) as pilot:
+        app.table_handler.populate_entries_table()
+        await pilot.press("shift+n")
+        await pilot.pause()
+
+        assert isinstance(app.screen, AddEntryModal)
+        assert app.focused is app.screen.query_one("#hostnames-input", Input)
+        await pilot.press("escape")
+        await pilot.pause()
+        assert not isinstance(app.screen, AddEntryModal)
+
+
 @pytest.mark.asyncio
 async def test_help_overlay_closes_to_the_control_that_opened_it():
     """Help is an overlay and returns keyboard focus to its opener."""