diff --git a/pyproject.toml b/pyproject.toml
index 74fa02c..15a5cf3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -67,3 +67,26 @@ init-hook='import sys; sys.path.append("src/")'
 testpaths = [
     "tests",
 ]
+
+
+[tool.coverage.run]
+omit = [
+    "*/tests/*",
+    "*/test_*.py",
+    "*/__init__.py"
+]
+
+[tool.coverage.report]
+exclude_lines = [
+    "pragma: no cover",
+    "def __repr__",
+    "def __str__",
+    "raise AssertionError",
+    "raise NotImplementedError",
+    "if __name__ == .__main__.:"
+]
+exclude_also = [
+    "def __.*__\\(",
+    "def __.*\\(",
+    "def _.*\\(",
+]
diff --git a/src/corelibs/json_handling/json_helper.py b/src/corelibs/json_handling/json_helper.py
index 6a80d82..fe4670b 100644
--- a/src/corelibs/json_handling/json_helper.py
+++ b/src/corelibs/json_handling/json_helper.py
@@ -13,7 +13,7 @@ from jsonpath_ng import parse  # pyright: ignore[reportMissingTypeStubs, reportU
 class DateTimeEncoder(JSONEncoder):
     """
     Override the default method
-    cls=DateTimeEncoder
+    dumps(..., cls=DateTimeEncoder, ...)
     """
     def default(self, o: Any) -> str | None:
         if isinstance(o, (date, datetime)):
@@ -21,10 +21,10 @@ class DateTimeEncoder(JSONEncoder):
         return None
 
 
-def default(obj: Any) -> str | None:
+def default_isoformat(obj: Any) -> str | None:
     """
     default override
-    default=default
+    dumps(..., default=default, ...)
     """
     if isinstance(obj, (date, datetime)):
         return obj.isoformat()
diff --git a/tests/unit/json_handling/test_json_helper.py b/tests/unit/json_handling/test_json_helper.py
index 8df3276..4acb990 100644
--- a/tests/unit/json_handling/test_json_helper.py
+++ b/tests/unit/json_handling/test_json_helper.py
@@ -7,7 +7,7 @@ from datetime import datetime, date
 from typing import Any
 from corelibs.json_handling.json_helper import (
     DateTimeEncoder,
-    default,
+    default_isoformat,
     json_dumps,
     modify_with_jsonpath
 )
@@ -132,30 +132,30 @@ class TestDefaultFunction:
     def test_default_datetime(self):
         """Test default function with datetime"""
         dt = datetime(2025, 10, 23, 15, 30, 45)
-        result = default(dt)
+        result = default_isoformat(dt)
         assert result == "2025-10-23T15:30:45"
 
     def test_default_date(self):
         """Test default function with date"""
         d = date(2025, 10, 23)
-        result = default(d)
+        result = default_isoformat(d)
         assert result == "2025-10-23"
 
     def test_default_with_microseconds(self):
         """Test default function with datetime including microseconds"""
         dt = datetime(2025, 10, 23, 15, 30, 45, 123456)
-        result = default(dt)
+        result = default_isoformat(dt)
         assert result == "2025-10-23T15:30:45.123456"
 
     def test_default_returns_none_for_other_types(self):
         """Test that default returns None for non-date/datetime objects"""
-        assert default("string") is None
-        assert default(42) is None
-        assert default(3.14) is None
-        assert default(True) is None
-        assert default(None) is None
-        assert default([1, 2, 3]) is None
-        assert default({"key": "value"}) is None
+        assert default_isoformat("string") is None
+        assert default_isoformat(42) is None
+        assert default_isoformat(3.14) is None
+        assert default_isoformat(True) is None
+        assert default_isoformat(None) is None
+        assert default_isoformat([1, 2, 3]) is None
+        assert default_isoformat({"key": "value"}) is None
 
     def test_default_as_json_default_parameter(self):
         """Test using default function as default parameter in json.dumps"""
@@ -165,7 +165,7 @@ class TestDefaultFunction:
             "name": "test"
         }
 
-        result = json.dumps(data, default=default)
+        result = json.dumps(data, default=default_isoformat)
         decoded = json.loads(result)
 
         assert decoded["timestamp"] == "2025-10-23T15:30:45"