Add test.

tests/components/sensor/test_template.py

@@ -0,0 +1,49 @@
+"""
+tests.components.sensor.template
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Tests template sensor.
+"""
+from unittest.mock import patch
+
+import pytest
+
+import homeassistant.core as ha
+import homeassistant.components.sensor as sensor
+
+
+@pytest.mark.usefixtures('betamax_session')
+class TestSensorYr:
+    """ Test the Yr sensor. """
+
+    def setup_method(self, method):
+        self.hass = ha.HomeAssistant()
+        self.hass.config.latitude = 32.87336
+        self.hass.config.longitude = 117.22743
+
+    def teardown_method(self, method):
+        """ Stop down stuff we started. """
+        self.hass.stop()
+
+    def test_template(self, betamax_session):
+        with patch('homeassistant.components.sensor.yr.requests.Session',
+                   return_value=betamax_session):
+            assert sensor.setup(self.hass, {
+                'sensor': {
+                    'platform': 'template',
+                    'sensors': {
+                        'test_template_sensor': {
+                            'value_template':
+                                '{{ states.sensor.test_state.state }}'
+                        }
+                    }
+                }
+            })
+
+        state = self.hass.states.get('sensor.test_template_sensor')
+        assert state.state == ''
+
+        self.hass.states.set('sensor.test_state', 'Works')
+        self.hass.pool.block_till_done()
+        state = self.hass.states.get('sensor.test_template_sensor')
+        assert state.state == 'Works'