Add tests for uncovered exception and edge-case branches

Cover five previously untested paths:
- `_get_position_time`: parse_datetime returns None (fallback to raw value)
- `_get_position_time`: parse_datetime raises ValueError (fallback to raw value)
- `_get_mode` / `_get_mode_attrs`: device.mode is None → returns None / {}
- `PetTracerDeviceTracker.available`: returns False when device absent from coordinator
- `async_step_reauth_confirm`: unknown exception → errors["base"] = "unknown"
Also assert `last_contact` key in device tracker attributes test.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kylegordon

tests/test_config_flow.py

@@ -218,6 +218,38 @@ async def test_reauth_flow_success(hass, mock_setup_entry):
     assert entry.data[CONF_PASSWORD] == "new_password"
 
 
+async def test_reauth_flow_unknown_exception(hass, mock_setup_entry):
+    """Test reauth flow with unexpected exception."""
+    from pytest_homeassistant_custom_component.common import MockConfigEntry
+
+    entry = MockConfigEntry(
+        domain=DOMAIN,
+        data={
+            CONF_USERNAME: "test@example.com",
+            CONF_PASSWORD: "old_password",
+        },
+        unique_id="test@example.com",
+    )
+    entry.add_to_hass(hass)
+
+    result = await entry.start_reauth_flow(hass)
+
+    with patch(
+        "custom_components.pettracer.config_flow.PetTracerClient"
+    ) as mock_client:
+        client_instance = MagicMock()
+        client_instance.login = AsyncMock(side_effect=Exception("Unexpected error"))
+        mock_client.return_value = client_instance
+
+        result2 = await hass.config_entries.flow.async_configure(
+            result["flow_id"],
+            {CONF_PASSWORD: "new_password"},
+        )
+
+    assert result2["type"] == FlowResultType.FORM
+    assert result2["errors"] == {"base": "unknown"}
+
+
 async def test_reauth_flow_invalid_auth(hass, mock_setup_entry):
     """Test reauth flow with invalid credentials."""
     from pytest_homeassistant_custom_component.common import MockConfigEntry

tests/test_device_tracker.py

@@ -132,6 +132,7 @@ async def test_device_tracker_attributes(hass, mock_device):
 
     assert "battery_voltage_mv" in attributes
     assert attributes["battery_voltage_mv"] == 4100
+    assert "last_contact" in attributes
     assert "satellites" in attributes
     assert attributes["satellites"] == 8
     assert "signal_strength" in attributes
@@ -246,6 +247,20 @@ async def test_device_tracker_no_details(hass):
     assert device_info["sw_version"] is None
 
 
+async def test_device_tracker_unavailable(hass, mock_device):
+    """Test device tracker available property when device is removed from coordinator."""
+    from custom_components.pettracer.device_tracker import PetTracerDeviceTracker
+
+    coordinator = MagicMock()
+    coordinator.data = {"devices": [mock_device]}
+
+    tracker = PetTracerDeviceTracker(coordinator, mock_device)
+    assert tracker.available is True
+
+    coordinator.data = {"devices": []}
+    assert tracker.available is False
+
+
 async def test_device_tracker_partial_attributes(hass):
     """Test device tracker with partial attribute data."""
     from custom_components.pettracer.device_tracker import PetTracerDeviceTracker

tests/test_sensor.py

@@ -367,6 +367,53 @@ async def test_sensor_no_details(hass):
     assert device_info["sw_version"] is None
 
 
+async def test_position_time_parse_returns_none(hass, mock_device):
+    """Test position time falls back to raw value when parse_datetime returns None."""
+    coordinator = MagicMock()
+    coordinator.data = {"devices": [mock_device]}
+
+    mock_device.lastPos.timeMeasure = "not-a-real-datetime"
+
+    description = next(d for d in SENSOR_DESCRIPTIONS if d.key == "position_time")
+    sensor = PetTracerSensor(coordinator, mock_device, description)
+
+    with patch(
+        "custom_components.pettracer.sensor.parse_datetime", return_value=None
+    ):
+        assert sensor.native_value == "not-a-real-datetime"
+
+
+async def test_position_time_parse_exception(hass, mock_device):
+    """Test position time falls back to raw value when parse_datetime raises."""
+    coordinator = MagicMock()
+    coordinator.data = {"devices": [mock_device]}
+
+    mock_device.lastPos.timeMeasure = "bad-value"
+
+    description = next(d for d in SENSOR_DESCRIPTIONS if d.key == "position_time")
+    sensor = PetTracerSensor(coordinator, mock_device, description)
+
+    with patch(
+        "custom_components.pettracer.sensor.parse_datetime",
+        side_effect=ValueError("unparseable"),
+    ):
+        assert sensor.native_value == "bad-value"
+
+
+async def test_mode_sensor_none_mode(hass, mock_device):
+    """Test mode sensor returns None when device.mode is None."""
+    coordinator = MagicMock()
+
+    description = next(d for d in SENSOR_DESCRIPTIONS if d.key == "mode")
+    sensor = PetTracerSensor(coordinator, mock_device, description)
+
+    mock_device.mode = None
+    coordinator.data = {"devices": [mock_device]}
+
+    assert sensor.native_value is None
+    assert sensor.extra_state_attributes == {}
+
+
 async def test_battery_percentage_edge_cases(hass, mock_device):
     """Test battery percentage calculation with edge cases."""
     coordinator = MagicMock()