Rows are internally tracked using RowKey in DataTable

tests/test_two_way_dict.py

@@ -0,0 +1,56 @@
+import pytest
+
+from textual._two_way_dict import TwoWayDict
+
+
+@pytest.fixture
+def map():
+    return TwoWayDict(
+        {
+            1: 10,
+            2: 20,
+            3: 30,
+        }
+    )
+
+
+def test_get(map):
+    assert map.get(1) == 10
+
+
+def test_get_default_none(map):
+    assert map.get(9999) is None
+
+
+def test_get_default_supplied(map):
+    assert map.get(9999, -123) == -123
+
+
+def test_get_key(map):
+    assert map.get_key(30) == 3
+
+
+def test_get_key_default_none(map):
+    assert map.get_key(9999) is None
+
+
+def test_get_key_default_supplied(map):
+    assert map.get_key(9999, -123) == -123
+
+
+def test_set_item(map):
+    map[40] = 400
+    assert map.get(40) == 400
+    assert map.get_key(400) == 40
+
+
+def test_len(map):
+    assert len(map) == 3
+
+
+def test_delitem(map):
+    assert map.get(3) == 30
+    assert map.get_key(30) == 3
+    del map[3]
+    assert map.get(3) is None
+    assert map.get_key(30) is None