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diff --git a/tests/test_utils.py b/tests/test_utils.py
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+++ b/tests/test_utils.py
@@ -0,0 +1,310 @@
+"""Test module for json2xml.utils functionality."""
+import json
+import tempfile
+from typing import TYPE_CHECKING
+from unittest.mock import Mock, patch
+
+import pytest
+
+from json2xml.utils import (
+    InvalidDataError,
+    JSONReadError,
+    StringReadError,
+    URLReadError,
+    readfromjson,
+    readfromstring,
+    readfromurl,
+)
+
+if TYPE_CHECKING:
+    from _pytest.capture import CaptureFixture
+    from _pytest.fixtures import FixtureRequest
+    from _pytest.logging import LogCaptureFixture
+    from _pytest.monkeypatch import MonkeyPatch
+    from pytest_mock.plugin import MockerFixture
+
+
+class TestExceptions:
+    """Test custom exception classes."""
+
+    def test_json_read_error(self) -> None:
+        """Test JSONReadError exception."""
+        with pytest.raises(JSONReadError) as exc_info:
+            raise JSONReadError("Test error message")
+        assert str(exc_info.value) == "Test error message"
+
+    def test_invalid_data_error(self) -> None:
+        """Test InvalidDataError exception."""
+        with pytest.raises(InvalidDataError) as exc_info:
+            raise InvalidDataError("Invalid data")
+        assert str(exc_info.value) == "Invalid data"
+
+    def test_url_read_error(self) -> None:
+        """Test URLReadError exception."""
+        with pytest.raises(URLReadError) as exc_info:
+            raise URLReadError("URL error")
+        assert str(exc_info.value) == "URL error"
+
+    def test_string_read_error(self) -> None:
+        """Test StringReadError exception."""
+        with pytest.raises(StringReadError) as exc_info:
+            raise StringReadError("String error")
+        assert str(exc_info.value) == "String error"
+
+
+class TestReadFromJson:
+    """Test readfromjson function."""
+
+    def test_readfromjson_valid_file(self) -> None:
+        """Test reading a valid JSON file."""
+        test_data = {"key": "value", "number": 42}
+
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            json.dump(test_data, f)
+            temp_filename = f.name
+
+        try:
+            result = readfromjson(temp_filename)
+            assert result == test_data
+        finally:
+            import os
+            os.unlink(temp_filename)
+
+    def test_readfromjson_invalid_json_content(self) -> None:
+        """Test reading a file with invalid JSON content."""
+        with tempfile.NamedTemporaryFile(mode='w', suffix='.json', delete=False) as f:
+            f.write('{"invalid": json content}')  # Invalid JSON
+            temp_filename = f.name
+
+        try:
+            with pytest.raises(JSONReadError, match="Invalid JSON File"):
+                readfromjson(temp_filename)
+        finally:
+            import os
+            os.unlink(temp_filename)
+
+    def test_readfromjson_file_not_found(self) -> None:
+        """Test reading a non-existent file."""
+        with pytest.raises(JSONReadError, match="Invalid JSON File"):
+            readfromjson("non_existent_file.json")
+
+    @patch('builtins.open')
+    def test_readfromjson_permission_error(self, mock_open: Mock) -> None:
+        """Test reading a file with permission issues."""
+        # Mock open to raise PermissionError
+        mock_open.side_effect = PermissionError("Permission denied")
+
+        with pytest.raises(JSONReadError, match="Invalid JSON File"):
+            readfromjson("some_file.json")
+
+    @patch('builtins.open')
+    def test_readfromjson_os_error(self, mock_open: Mock) -> None:
+        """Test reading a file with OS error."""
+        # Mock open to raise OSError (covers line 34-35 in utils.py)
+        mock_open.side_effect = OSError("Device not ready")
+
+        with pytest.raises(JSONReadError, match="Invalid JSON File"):
+            readfromjson("some_file.json")
+
+
+class TestReadFromUrl:
+    """Test readfromurl function."""
+
+    @patch('json2xml.utils.urllib3.PoolManager')
+    def test_readfromurl_success(self, mock_pool_manager: Mock) -> None:
+        """Test successful URL reading."""
+        # Mock response
+        mock_response = Mock()
+        mock_response.status = 200
+        mock_response.data = b'{"key": "value", "number": 42}'
+
+        # Mock PoolManager
+        mock_http = Mock()
+        mock_http.request.return_value = mock_response
+        mock_pool_manager.return_value = mock_http
+
+        result = readfromurl("http://example.com/data.json")
+
+        assert result == {"key": "value", "number": 42}
+        mock_pool_manager.assert_called_once()
+        mock_http.request.assert_called_once_with("GET", "http://example.com/data.json", fields=None)
+
+    @patch('json2xml.utils.urllib3.PoolManager')
+    def test_readfromurl_success_with_params(self, mock_pool_manager: Mock) -> None:
+        """Test successful URL reading with parameters."""
+        # Mock response
+        mock_response = Mock()
+        mock_response.status = 200
+        mock_response.data = b'{"result": "success"}'
+
+        # Mock PoolManager
+        mock_http = Mock()
+        mock_http.request.return_value = mock_response
+        mock_pool_manager.return_value = mock_http
+
+        params = {"param1": "value1", "param2": "value2"}
+        result = readfromurl("http://example.com/api", params=params)
+
+        assert result == {"result": "success"}
+        mock_http.request.assert_called_once_with("GET", "http://example.com/api", fields=params)
+
+    @patch('json2xml.utils.urllib3.PoolManager')
+    def test_readfromurl_http_error(self, mock_pool_manager: Mock) -> None:
+        """Test URL reading with HTTP error status."""
+        # Mock response with error status
+        mock_response = Mock()
+        mock_response.status = 404
+
+        # Mock PoolManager
+        mock_http = Mock()
+        mock_http.request.return_value = mock_response
+        mock_pool_manager.return_value = mock_http
+
+        with pytest.raises(URLReadError, match="URL is not returning correct response"):
+            readfromurl("http://example.com/nonexistent.json")
+
+    @patch('json2xml.utils.urllib3.PoolManager')
+    def test_readfromurl_server_error(self, mock_pool_manager: Mock) -> None:
+        """Test URL reading with server error status."""
+        # Mock response with server error status
+        mock_response = Mock()
+        mock_response.status = 500
+
+        # Mock PoolManager
+        mock_http = Mock()
+        mock_http.request.return_value = mock_response
+        mock_pool_manager.return_value = mock_http
+
+        with pytest.raises(URLReadError, match="URL is not returning correct response"):
+            readfromurl("http://example.com/error.json")
+
+    @patch('json2xml.utils.urllib3.PoolManager')
+    def test_readfromurl_invalid_json_response(self, mock_pool_manager: Mock) -> None:
+        """Test URL reading with invalid JSON response."""
+        # Mock response with invalid JSON
+        mock_response = Mock()
+        mock_response.status = 200
+        mock_response.data = b'invalid json content'
+
+        # Mock PoolManager
+        mock_http = Mock()
+        mock_http.request.return_value = mock_response
+        mock_pool_manager.return_value = mock_http
+
+        with pytest.raises(json.JSONDecodeError):
+            readfromurl("http://example.com/invalid.json")
+
+
+class TestReadFromString:
+    """Test readfromstring function."""
+
+    def test_readfromstring_valid_json(self) -> None:
+        """Test reading valid JSON string."""
+        json_string = '{"key": "value", "number": 42, "boolean": true}'
+        result = readfromstring(json_string)
+        assert result == {"key": "value", "number": 42, "boolean": True}
+
+    def test_readfromstring_empty_object(self) -> None:
+        """Test reading empty JSON object."""
+        json_string = '{}'
+        result = readfromstring(json_string)
+        assert result == {}
+
+    def test_readfromstring_complex_object(self) -> None:
+        """Test reading complex JSON object."""
+        json_string = '{"users": [{"name": "John", "age": 30}, {"name": "Jane", "age": 25}], "total": 2}'
+        result = readfromstring(json_string)
+        expected = {
+            "users": [
+                {"name": "John", "age": 30},
+                {"name": "Jane", "age": 25}
+            ],
+            "total": 2
+        }
+        assert result == expected
+
+    def test_readfromstring_invalid_type_int(self) -> None:
+        """Test reading with integer input."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring(123)  # type: ignore[arg-type]
+
+    def test_readfromstring_invalid_type_list(self) -> None:
+        """Test reading with list input."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring(["not", "a", "string"])  # type: ignore[arg-type]
+
+    def test_readfromstring_invalid_type_dict(self) -> None:
+        """Test reading with dict input."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring({"not": "a string"})  # type: ignore[arg-type]
+
+    def test_readfromstring_invalid_type_none(self) -> None:
+        """Test reading with None input."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring(None)  # type: ignore[arg-type]
+
+    def test_readfromstring_invalid_json_syntax(self) -> None:
+        """Test reading string with invalid JSON syntax."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring('{"invalid": json, syntax}')
+
+    def test_readfromstring_invalid_json_incomplete(self) -> None:
+        """Test reading incomplete JSON string."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring('{"incomplete":')
+
+    def test_readfromstring_invalid_json_extra_comma(self) -> None:
+        """Test reading JSON string with trailing comma."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring('{"key": "value",}')
+
+    def test_readfromstring_invalid_json_single_quotes(self) -> None:
+        """Test reading JSON string with single quotes."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring("{'key': 'value'}")
+
+    def test_readfromstring_empty_string(self) -> None:
+        """Test reading empty string."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring("")
+
+    def test_readfromstring_plain_text(self) -> None:
+        """Test reading plain text."""
+        with pytest.raises(StringReadError, match="Input is not a proper JSON string"):
+            readfromstring("this is just plain text")
+
+
+class TestIntegration:
+    """Integration tests combining multiple utilities."""
+
+    def test_readfromstring_then_convert_to_xml(self) -> None:
+        """Test reading JSON string and converting to XML."""
+        from json2xml import dicttoxml
+
+        json_string = '{"name": "test", "value": 123}'
+        data = readfromstring(json_string)
+        xml_result = dicttoxml.dicttoxml(data, attr_type=False, root=False)
+
+        assert b"<name>test</name>" in xml_result
+        assert b"<value>123</value>" in xml_result
+
+    @patch('json2xml.utils.urllib3.PoolManager')
+    def test_readfromurl_then_convert_to_xml(self, mock_pool_manager: Mock) -> None:
+        """Test reading from URL and converting to XML."""
+        from json2xml import dicttoxml
+
+        # Mock response
+        mock_response = Mock()
+        mock_response.status = 200
+        mock_response.data = b'{"api": "response", "status": "ok"}'
+
+        # Mock PoolManager
+        mock_http = Mock()
+        mock_http.request.return_value = mock_response
+        mock_pool_manager.return_value = mock_http
+
+        data = readfromurl("http://example.com/api.json")
+        xml_result = dicttoxml.dicttoxml(data, attr_type=False, root=False)
+
+        assert b"<api>response</api>" in xml_result
+        assert b"<status>ok</status>" in xml_result