diff --git a/pyproject.toml b/pyproject.toml
index f0cdd972..33e5f55e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -101,6 +101,8 @@ include = [
   "serde/toml.py",
   "serde/yaml.py",
   "serde/pickle.py",
+  "tests/common.py",
+  "tests/imported.py",
   "tests/test_custom.py",
   "tests/test_kwonly.py",
   "tests/test_flatten.py",
@@ -111,8 +113,6 @@ include = [
 exclude = [
   "serde/numpy.py",
   "bench",
-  "tests/common.py",
-  "tests/imported.py",
   "tests/test_basics.py",
   "tests/test_compat.py",
   "tests/test_core.py",
@@ -135,8 +135,6 @@ exclude = [
   "examples/alias.py",
   "examples/field_order.py",
   "bench",
-  "tests/common.py",
-  "tests/imported.py",
   "tests/test_basics.py",
   "tests/test_compat.py",
   "tests/test_core.py",
diff --git a/tests/common.py b/tests/common.py
index 99daf12d..5defdb99 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -180,7 +180,7 @@ def yaml_not_supported(se: Any, de: Any, opt: Any) -> bool:
         [param([1, 2], list[int]), param({"a": 1}, dict[str, int]), param((1, 1), tuple[int, int])]
     )
 
-types_combinations: List = [
+types_combinations: List[Any] = [
     list(more_itertools.flatten(c)) for c in itertools.combinations(types, 2)
 ]
 
@@ -191,7 +191,7 @@ def yaml_not_supported(se: Any, de: Any, opt: Any) -> bool:
 ]
 
 
-def make_id_from_dict(d: Dict[str, str]) -> str:
+def make_id_from_dict(d: Dict[str, Union[bool, str]]) -> str:
     if not d:
         return "none"
     else:
@@ -199,24 +199,33 @@ def make_id_from_dict(d: Dict[str, str]) -> str:
         return f"{key}-{d[key]}"
 
 
-def opt_case_ids():
+def opt_case_ids() -> List[str]:
+    """
+    Create parametrize test id
+    """
     return list(map(make_id_from_dict, opt_case))
 
 
-def type_ids():
+def type_ids() -> List[str]:
+    """
+    Create parametrize test id
+    """
     from serde.compat import typename
 
-    def make_id(pair: Tuple):
+    def make_id(pair: Tuple[Any, ...]) -> str:
         t, T, _ = pair
         return f"{typename(T)}({t})"
 
     return list(map(make_id, types))
 
 
-def type_combinations_ids():
+def type_combinations_ids() -> List[str]:
+    """
+    Create parametrize test id
+    """
     from serde.compat import typename
 
-    def make_id(quad: Tuple):
+    def make_id(quad: Tuple[Any, ...]) -> str:
         t, T, u, U = quad
         return f"{typename(T)}({t})-{typename(U)}({u})"
 
diff --git a/tests/test_de.py b/tests/test_de.py
index cb9503e8..00927044 100644
--- a/tests/test_de.py
+++ b/tests/test_de.py
@@ -5,7 +5,7 @@
 from serde.de import from_obj
 
 
-def test_from_obj():
+def test_from_obj() -> None:
     # Primitive
     assert 10 == from_obj(int, 10, False, False)