tests/functional2: fixes prerequisite to ruff upgrade to 0.11.10

Most of these are simple fixes and clarifications. One set of fixes will
come in the commit that actually upgrades nixpkgs and hence ruff as it
will otherwise cause errors here.

Change-Id: Ie857da0f6cf728478700ec2d24cf518f8c7b7815

tests/functional2/testlib/test_utils.py

@@ -43,15 +43,15 @@ def test_type_doesnt_allow_generator():
     def foo():
         yield 1
 
-    with pytest.raises(ValueError, match="Unsupported expected_type.+"):
+    with pytest.raises(ValueError, match=r"Unsupported expected_type.+"):
         is_value_of_type(foo, Generator[int, None, None])
 
 
 def test_type_doesnt_allow_callable():
-    def foo(a):  # noqa: ANN001, ANN202: dummy stuff within testing, nothing external
+    def foo(a):  # noqa: ANN001, ANN202 # dummy stuff within testing, nothing external
         return "a" + str(a)
 
-    with pytest.raises(ValueError, match="Unsupported expected_type.+"):
+    with pytest.raises(ValueError, match=r"Unsupported expected_type.+"):
         is_value_of_type(foo, Callable[[int], str])
 
 
@@ -62,7 +62,7 @@ def test_type_allows_none():
 def test_doesnt_allow_generic():
     class X[T]: ...
 
-    with pytest.raises(ValueError, match="Unsupported expected_type.+"):
+    with pytest.raises(ValueError, match=r"Unsupported expected_type.+"):
         is_value_of_type(0, X[int])