diff --git a/src/time/test/time_server_test.py b/src/time/test/time_server_test.py
new file mode 100644
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--- /dev/null
+++ b/src/time/test/time_server_test.py
@@ -0,0 +1,495 @@
+import os
+
+from freezegun import freeze_time
+import pytest
+
+from mcp_server_time.server import TimeServer
+
+
+@pytest.mark.parametrize(
+    "test_time,timezone,expected",
+    [
+        # UTC+1 non-DST
+        (
+            "2024-01-01 12:00:00+00:00",
+            "Europe/Warsaw",
+            {
+                "timezone": "Europe/Warsaw",
+                "datetime": "2024-01-01T13:00:00+01:00",
+                "is_dst": False,
+            },
+        ),
+        # UTC non-DST
+        (
+            "2024-01-01 12:00:00+00:00",
+            "Europe/London",
+            {
+                "timezone": "Europe/London",
+                "datetime": "2024-01-01T12:00:00+00:00",
+                "is_dst": False,
+            },
+        ),
+        # UTC-5 non-DST
+        (
+            "2024-01-01 12:00:00-00:00",
+            "America/New_York",
+            {
+                "timezone": "America/New_York",
+                "datetime": "2024-01-01T07:00:00-05:00",
+                "is_dst": False,
+            },
+        ),
+        # UTC+1 DST
+        (
+            "2024-03-31 12:00:00+00:00",
+            "Europe/Warsaw",
+            {
+                "timezone": "Europe/Warsaw",
+                "datetime": "2024-03-31T14:00:00+02:00",
+                "is_dst": True,
+            },
+        ),
+        # UTC DST
+        (
+            "2024-03-31 12:00:00+00:00",
+            "Europe/London",
+            {
+                "timezone": "Europe/London",
+                "datetime": "2024-03-31T13:00:00+01:00",
+                "is_dst": True,
+            },
+        ),
+        # UTC-5 DST
+        (
+            "2024-03-31 12:00:00-00:00",
+            "America/New_York",
+            {
+                "timezone": "America/New_York",
+                "datetime": "2024-03-31T08:00:00-04:00",
+                "is_dst": True,
+            },
+        ),
+    ],
+)
+def test_get_current_time(test_time, timezone, expected):
+    with freeze_time(test_time):
+        time_server = TimeServer()
+        result = time_server.get_current_time(timezone)
+        assert result.timezone == expected["timezone"]
+        assert result.datetime == expected["datetime"]
+        assert result.is_dst == expected["is_dst"]
+
+
+def test_get_current_time_with_invalid_timezone():
+    time_server = TimeServer()
+    with pytest.raises(ValueError, match=r"Unknown timezone: 'Invalid/Timezone'"):
+        time_server.get_current_time("Invalid/Timezone")
+
+
+@pytest.mark.parametrize(
+    "source_tz,time_str,target_tz,expected_error",
+    [
+        (
+            "invalid_tz",
+            "12:00",
+            "Europe/London",
+            "Unknown source timezone: 'invalid_tz'",
+        ),
+        (
+            "Europe/Warsaw",
+            "12:00",
+            "invalid_tz",
+            "Unknown target timezone: 'invalid_tz'",
+        ),
+        (
+            "Europe/Warsaw",
+            "25:00",
+            "Europe/London",
+            "Invalid time format. Expected HH:MM [24-hour format]",
+        ),
+    ],
+)
+def test_convert_time_errors(source_tz, time_str, target_tz, expected_error):
+    time_server = TimeServer()
+    with pytest.raises(ValueError, match=expected_error):
+        time_server.convert_time(source_tz, time_str, target_tz)
+
+
+@pytest.mark.parametrize(
+    "test_time,source_tz,time_str,target_tz,expected",
+    [
+        # Basic case: Standard time conversion between Warsaw and London (1 hour difference)
+        # Warsaw is UTC+1, London is UTC+0
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Europe/London",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Europe/London",
+                    "datetime": "2024-01-01T11:00:00+00:00",
+                    "is_dst": False,
+                },
+                "time_difference": "-1.0h",
+            },
+        ),
+        # Reverse case of above: London to Warsaw conversion
+        # Shows how time difference is positive when going east
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/London",
+            "12:00",
+            "Europe/Warsaw",
+            {
+                "source": {
+                    "timezone": "Europe/London",
+                    "datetime": "2024-01-01T12:00:00+00:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T13:00:00+01:00",
+                    "is_dst": False,
+                },
+                "time_difference": "+1.0h",
+            },
+        ),
+        # Edge case: Different DST periods between Europe and USA
+        # Europe ends DST on Oct 27, while USA waits until Nov 3
+        # This creates a one-week period where Europe is in standard time but USA still observes DST
+        (
+            "2024-10-28 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "America/New_York",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-10-28T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "America/New_York",
+                    "datetime": "2024-10-28T07:00:00-04:00",
+                    "is_dst": True,
+                },
+                "time_difference": "-5.0h",
+            },
+        ),
+        # Follow-up to previous case: After both regions end DST
+        # Shows how time difference increases by 1 hour when USA also ends DST
+        (
+            "2024-11-04 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "America/New_York",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-11-04T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "America/New_York",
+                    "datetime": "2024-11-04T06:00:00-05:00",
+                    "is_dst": False,
+                },
+                "time_difference": "-6.0h",
+            },
+        ),
+        # Edge case: Nepal's unusual UTC+5:45 offset
+        # One of the few time zones using 45-minute offset
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Asia/Kathmandu",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Asia/Kathmandu",
+                    "datetime": "2024-01-01T16:45:00+05:45",
+                    "is_dst": False,
+                },
+                "time_difference": "+4.75h",
+            },
+        ),
+        # Reverse case for Nepal
+        # Demonstrates how 45-minute offset works in opposite direction
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Asia/Kathmandu",
+            "12:00",
+            "Europe/Warsaw",
+            {
+                "source": {
+                    "timezone": "Asia/Kathmandu",
+                    "datetime": "2024-01-01T12:00:00+05:45",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T07:15:00+01:00",
+                    "is_dst": False,
+                },
+                "time_difference": "-4.75h",
+            },
+        ),
+        # Edge case: Lord Howe Island's unique DST rules
+        # One of the few places using 30-minute DST shift
+        # During summer (DST), they use UTC+11
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Australia/Lord_Howe",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Australia/Lord_Howe",
+                    "datetime": "2024-01-01T22:00:00+11:00",
+                    "is_dst": True,
+                },
+                "time_difference": "+10.0h",
+            },
+        ),
+        # Second Lord Howe Island case: During their standard time
+        # Shows transition to UTC+10:30 after DST ends
+        (
+            "2024-04-07 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Australia/Lord_Howe",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-04-07T12:00:00+02:00",
+                    "is_dst": True,
+                },
+                "target": {
+                    "timezone": "Australia/Lord_Howe",
+                    "datetime": "2024-04-07T20:30:00+10:30",
+                    "is_dst": False,
+                },
+                "time_difference": "+8.5h",
+            },
+        ),
+        # Edge case: Date line crossing with Samoa
+        # Demonstrates how a single time conversion can result in a date change
+        # Samoa is UTC+13, creating almost a full day difference with Warsaw
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/Warsaw",
+            "23:00",
+            "Pacific/Apia",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T23:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Pacific/Apia",
+                    "datetime": "2024-01-02T11:00:00+13:00",
+                    "is_dst": False,
+                },
+                "time_difference": "+12.0h",
+            },
+        ),
+        # Edge case: Iran's unusual half-hour offset
+        # Demonstrates conversion with Iran's UTC+3:30 timezone
+        (
+            "2024-03-21 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Asia/Tehran",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-03-21T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Asia/Tehran",
+                    "datetime": "2024-03-21T14:30:00+03:30",
+                    "is_dst": False,
+                },
+                "time_difference": "+2.5h",
+            },
+        ),
+        # Edge case: Venezuela's unusual -4:30 offset (historical)
+        # In 2016, Venezuela moved from -4:30 to -4:00
+        # Useful for testing historical dates
+        (
+            "2016-04-30 00:00:00+00:00",  # Just before the change
+            "Europe/Warsaw",
+            "12:00",
+            "America/Caracas",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2016-04-30T12:00:00+02:00",
+                    "is_dst": True,
+                },
+                "target": {
+                    "timezone": "America/Caracas",
+                    "datetime": "2016-04-30T05:30:00-04:30",
+                    "is_dst": False,
+                },
+                "time_difference": "-6.5h",
+            },
+        ),
+        # Edge case: Israel's variable DST
+        # Israel's DST changes don't follow a fixed pattern
+        # They often change dates year-to-year based on Hebrew calendar
+        (
+            "2024-10-27 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Asia/Jerusalem",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-10-27T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Asia/Jerusalem",
+                    "datetime": "2024-10-27T13:00:00+02:00",
+                    "is_dst": False,
+                },
+                "time_difference": "+1.0h",
+            },
+        ),
+        # Edge case: Antarctica/Troll station
+        # Only timezone that uses UTC+0 in winter and UTC+2 in summer
+        # One of the few zones with exactly 2 hours DST difference
+        (
+            "2024-03-31 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Antarctica/Troll",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-03-31T12:00:00+02:00",
+                    "is_dst": True,
+                },
+                "target": {
+                    "timezone": "Antarctica/Troll",
+                    "datetime": "2024-03-31T12:00:00+02:00",
+                    "is_dst": True,
+                },
+                "time_difference": "+0.0h",
+            },
+        ),
+        # Edge case: Kiribati date line anomaly
+        # After skipping Dec 31, 1994, eastern Kiribati is UTC+14
+        # The furthest forward timezone in the world
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/Warsaw",
+            "23:00",
+            "Pacific/Kiritimati",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T23:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Pacific/Kiritimati",
+                    "datetime": "2024-01-02T12:00:00+14:00",
+                    "is_dst": False,
+                },
+                "time_difference": "+13.0h",
+            },
+        ),
+        # Edge case: Chatham Islands, New Zealand
+        # Uses unusual 45-minute offset AND observes DST
+        # UTC+12:45 in standard time, UTC+13:45 in DST
+        (
+            "2024-01-01 00:00:00+00:00",
+            "Europe/Warsaw",
+            "12:00",
+            "Pacific/Chatham",
+            {
+                "source": {
+                    "timezone": "Europe/Warsaw",
+                    "datetime": "2024-01-01T12:00:00+01:00",
+                    "is_dst": False,
+                },
+                "target": {
+                    "timezone": "Pacific/Chatham",
+                    "datetime": "2024-01-02T00:45:00+13:45",
+                    "is_dst": True,
+                },
+                "time_difference": "+12.75h",
+            },
+        ),
+    ],
+)
+def test_convert_time(test_time, source_tz, time_str, target_tz, expected):
+    with freeze_time(test_time):
+        time_server = TimeServer()
+        result = time_server.convert_time(source_tz, time_str, target_tz)
+
+        assert result.source.timezone == expected["source"]["timezone"]
+        assert result.target.timezone == expected["target"]["timezone"]
+        assert result.source.datetime == expected["source"]["datetime"]
+        assert result.target.datetime == expected["target"]["datetime"]
+        assert result.source.is_dst == expected["source"]["is_dst"]
+        assert result.target.is_dst == expected["target"]["is_dst"]
+        assert result.time_difference == expected["time_difference"]
+
+
+# @pytest.mark.anyio
+# async def test_call_tool(mock_forecast_response):
+#     class Response():
+#         def raise_for_status(self):
+#             pass
+
+#         def json(self):
+#             return mock_forecast_response
+
+#     class AsyncClient():
+#         def __aenter__(self):
+#             return self
+
+#         async def __aexit__(self, *exc_info):
+#             pass
+
+#         async def get(self, *args, **kwargs):
+#             return Response()
+
+#     with patch('httpx.AsyncClient', new=AsyncClient) as mock_client:
+#         result = await call_tool("get_forecast", {"city": "London", "days": 2})
+
+#         assert len(result) == 1
+#         assert result[0].type == "text"
+#         forecast_data = json.loads(result[0].text)
+#         assert len(forecast_data) == 1
+#         assert forecast_data[0]["temperature"] == 18.5
+#         assert forecast_data[0]["conditions"] == "sunny"
+
+
+# @pytest.mark.anyio
+# async def test_list_tools():
+#     tools = await list_tools()
+#     assert len(tools) == 1
+#     assert tools[0].name == "get_forecast"
+#     assert "city" in tools[0].inputSchema["properties"]