Improve demo test coverage (#77301)

tests/components/demo/test_sensor.py

@@ -0,0 +1,59 @@
+"""The tests for the demo sensor component."""
+from datetime import timedelta
+
+import pytest
+
+from homeassistant import core as ha
+from homeassistant.components.demo import DOMAIN
+from homeassistant.components.sensor import DOMAIN as SENSOR_DOMAIN
+from homeassistant.setup import async_setup_component
+
+from tests.common import mock_restore_cache_with_extra_data
+
+
+@pytest.mark.parametrize("entity_id, delta", (("sensor.total_energy_kwh", 0.5),))
+async def test_energy_sensor(hass: ha.HomeAssistant, entity_id, delta, freezer):
+    """Test energy sensors increase periodically."""
+    assert await async_setup_component(
+        hass, SENSOR_DOMAIN, {SENSOR_DOMAIN: {"platform": DOMAIN}}
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get(entity_id)
+    assert state.state == "0"
+
+    freezer.tick(timedelta(minutes=5, seconds=1))
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+
+    state = hass.states.get(entity_id)
+    assert state.state == str(delta)
+
+
+@pytest.mark.parametrize("entity_id, delta", (("sensor.total_energy_kwh", 0.5),))
+async def test_restore_state(hass: ha.HomeAssistant, entity_id, delta, freezer):
+    """Test energy sensors restore state."""
+    fake_state = ha.State(
+        entity_id,
+        "",
+    )
+    fake_extra_data = {
+        "native_value": 2**20,
+        "native_unit_of_measurement": None,
+    }
+    mock_restore_cache_with_extra_data(hass, ((fake_state, fake_extra_data),))
+
+    assert await async_setup_component(
+        hass, SENSOR_DOMAIN, {SENSOR_DOMAIN: {"platform": DOMAIN}}
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get(entity_id)
+    assert state.state == str(2**20)
+
+    freezer.tick(timedelta(minutes=5, seconds=1))
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+
+    state = hass.states.get(entity_id)
+    assert state.state == str(2**20 + delta)