test_ignore_env_name_mismatch: unit tests for FilteredInfo

Since FilteredInfo can accept generic filter_keys and filter_section, add test
cases to ensure the less common default branches are covered, even though the
plugins don't directly use them (yet)

tests/unit/test_ignore_env_name_mismatch.py

@@ -1,3 +1,4 @@
+import json
 from unittest import mock
 
 from tox.tox_env.api import ToxEnv, ToxEnvCreateArgs
@@ -46,3 +47,87 @@ def test_reusable_virtualenv_runner_cache(env_name, tox_env):
 
     assert info._content
     assert not info._content[ToxEnv.__name__]
+
+
+SECTION_BLANK = ""
+SECTION_FOO = "foo"
+TOP_LEVEL_KEY_BLANK = {"empty": None}
+TOP_LEVEL_KEY_FOO = {"bar": None}
+
+
+@pytest.fixture
+def cached_info(tmp_path):
+    content = {
+        SECTION_BLANK: TOP_LEVEL_KEY_BLANK.copy(),
+        SECTION_FOO: TOP_LEVEL_KEY_FOO.copy(),
+    }
+    (tmp_path / ".tox-info.json").write_text(json.dumps(content))
+    return content
+
+
+@pytest.mark.usefixtures("cached_info")
+@pytest.mark.parametrize(
+    ("filter_keys", "filter_section", "args", "exp_eq", "exp_old"),
+    [
+        (None, None, ({}, SECTION_BLANK), False, TOP_LEVEL_KEY_BLANK),
+        (None, None, (TOP_LEVEL_KEY_BLANK, SECTION_BLANK), True, TOP_LEVEL_KEY_BLANK),
+        (
+            None,
+            None,
+            ({"foo": "bar", **TOP_LEVEL_KEY_BLANK}, SECTION_BLANK),
+            False,
+            TOP_LEVEL_KEY_BLANK,
+        ),
+        (
+            ["foo"],
+            None,
+            ({"foo": "bar", **TOP_LEVEL_KEY_BLANK}, SECTION_BLANK),
+            True,
+            TOP_LEVEL_KEY_BLANK,
+        ),
+        (
+            ["foo"],
+            None,
+            ({"foo": "bar", **TOP_LEVEL_KEY_FOO}, SECTION_FOO),
+            True,
+            TOP_LEVEL_KEY_FOO,
+        ),
+        (
+            ["foo"],
+            SECTION_FOO,
+            ({"foo": "bar", **TOP_LEVEL_KEY_BLANK}, SECTION_BLANK),
+            False,
+            TOP_LEVEL_KEY_BLANK,
+        ),
+        (
+            ["foo"],
+            SECTION_FOO,
+            ({"foo": "bar", **TOP_LEVEL_KEY_FOO}, SECTION_FOO),
+            True,
+            TOP_LEVEL_KEY_FOO,
+        ),
+        (
+            ["foo"],
+            SECTION_FOO,
+            (TOP_LEVEL_KEY_FOO, SECTION_FOO),
+            True,
+            TOP_LEVEL_KEY_FOO,
+        ),
+        (
+            ["bar"],
+            SECTION_FOO,
+            (TOP_LEVEL_KEY_FOO, SECTION_FOO),
+            False,
+            TOP_LEVEL_KEY_FOO,
+        ),
+    ],
+)
+def test_filtered_info(tmp_path, filter_keys, filter_section, args, exp_eq, exp_old):
+    info = tox_ignore_env_name_mismatch.FilteredInfo(
+        tmp_path,
+        filter_keys=filter_keys,
+        filter_section=filter_section,
+    )
+    with info.compare(*args) as (eq, old):
+        assert eq == exp_eq
+        assert old == exp_old