diff --git a/maint_tools/test_docstrings.py b/maint_tools/test_docstrings.py
index 1a8c8b3297110..2861303c796b4 100644
--- a/maint_tools/test_docstrings.py
+++ b/maint_tools/test_docstrings.py
@@ -34,15 +34,22 @@
 
 def get_all_methods():
     estimators = all_estimators()
-    for name, estimator in estimators:
+    for name, Estimator in estimators:
         if name.startswith("_"):
             # skip private classes
             continue
-        methods = [el for el in dir(estimator) if not el.startswith("_")]
+        methods = []
+        for name in dir(Estimator):
+            if name.startswith("_"):
+                continue
+            method_obj = getattr(Estimator, name)
+            if (hasattr(method_obj, '__call__')
+                    or isinstance(method_obj, property)):
+                methods.append(name)
         methods.append(None)
 
         for method in sorted(methods, key=lambda x: str(x)):
-            yield estimator, method
+            yield Estimator, method
 
 
 def filter_errors(errors, method):
@@ -102,7 +109,16 @@ def repr_errors(res, estimator=None, method: Optional[str] = None) -> str:
             raise NotImplementedError
 
     if estimator is not None:
-        obj_signature = signature(getattr(estimator, method))
+        obj = getattr(estimator, method)
+        try:
+            obj_signature = signature(obj)
+        except TypeError:
+            # In particular we can't parse the signature of properties
+            obj_signature = (
+                    "\nParsing of the method signature failed, "
+                    "possibly because this is a property."
+            )
+
         obj_name = estimator.__name__ + "." + method
     else:
         obj_signature = ""
@@ -110,7 +126,7 @@ def repr_errors(res, estimator=None, method: Optional[str] = None) -> str:
 
     msg = "\n\n" + "\n\n".join(
         [
-            res["file"],
+            str(res["file"]),
             obj_name + str(obj_signature),
             res["docstring"],
             "# Errors",
@@ -123,10 +139,10 @@ def repr_errors(res, estimator=None, method: Optional[str] = None) -> str:
     return msg
 
 
-@pytest.mark.parametrize("estimator, method", get_all_methods())
-def test_docstring(estimator, method, request):
-    base_import_path = estimator.__module__
-    import_path = [base_import_path, estimator.__name__]
+@pytest.mark.parametrize("Estimator, method", get_all_methods())
+def test_docstring(Estimator, method, request):
+    base_import_path = Estimator.__module__
+    import_path = [base_import_path, Estimator.__name__]
     if method is not None:
         import_path.append(method)
 
@@ -144,7 +160,7 @@ def test_docstring(estimator, method, request):
     res["errors"] = list(filter_errors(res["errors"], method))
 
     if res["errors"]:
-        msg = repr_errors(res, estimator, method)
+        msg = repr_errors(res, Estimator, method)
 
         raise ValueError(msg)