Add a test for brain_gi

Just a simple one, that checks if the correct Gtk version gets
installed.

Note this test is checks for the linked regression only if both Gtk3 and
Gtk4 are installed. Otherwise, it checks if brain_gi works at all.

tests/brain/test_gi.py

@@ -0,0 +1,41 @@
+# Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
+# For details: https://github.com/pylint-dev/astroid/blob/main/LICENSE
+# Copyright (c) https://github.com/pylint-dev/astroid/blob/main/CONTRIBUTORS.txt
+
+import warnings
+from importlib.util import find_spec
+
+import pytest
+
+from astroid import Uninferable, extract_node
+from astroid.bases import BoundMethod
+from astroid.manager import AstroidManager
+
+HAS_GI = find_spec("gi")
+
+
+@pytest.mark.skipif(HAS_GI is None, reason="These tests require the gi library.")
+class TestBrainGi:
+    AstroidManager.brain["extension_package_whitelist"] = {"gi"}  # noqa: RUF012
+
+    @staticmethod
+    def test_import() -> None:
+        """Regression test for https://github.com/pylint-dev/astroid/issues/2190"""
+        src = """
+        import gi
+        gi.require_version('Gtk', '3.0')
+        from gi.repository import Gtk
+
+        cell = Gtk.CellRendererText()
+        cell.props.xalign = 1.0
+
+        Gtk.Builder().connect_signals
+        """
+        with warnings.catch_warnings():
+            # gi uses pkgutil.get_loader
+            warnings.filterwarnings("ignore", category=DeprecationWarning)
+            node = extract_node(src)
+        attribute_node = node.inferred()[0]
+        if attribute_node is Uninferable:
+            pytest.skip("Gtk3 may not be installed?")
+        assert isinstance(attribute_node, BoundMethod)