Swedish weather institute weather component (#16717)

* SMHI Component

* Clean up typos

* Fixed default values first config to home location (tests will follow)

* Fixed tests and removed unused function

* Minor fixup after comments from @kane610

* add support for precipitation in forecast

* Removed old async_step_init not needed.

tests/components/smhi/test_init.py

@@ -0,0 +1,39 @@
+"""Test SMHI component setup process."""
+from unittest.mock import Mock
+
+from homeassistant.components import smhi
+
+from .common import AsyncMock
+
+TEST_CONFIG = {
+    "config": {
+        "name": "0123456789ABCDEF",
+        "longitude": "62.0022",
+        "latitude": "17.0022"
+    }
+}
+
+
+async def test_setup_always_return_true() -> None:
+    """Test async_setup always returns True."""
+    hass = Mock()
+    # Returns true with empty config
+    assert await smhi.async_setup(hass, {}) is True
+
+    # Returns true with a config provided
+    assert await smhi.async_setup(hass, TEST_CONFIG) is True
+
+
+async def test_forward_async_setup_entry() -> None:
+    """Test that it will forward setup entry."""
+    hass = Mock()
+
+    assert await smhi.async_setup_entry(hass, {}) is True
+    assert len(hass.config_entries.async_forward_entry_setup.mock_calls) == 1
+
+
+async def test_forward_async_unload_entry() -> None:
+    """Test that it will forward unload entry."""
+    hass = AsyncMock()
+    assert await smhi.async_unload_entry(hass, {}) is True
+    assert len(hass.config_entries.async_forward_entry_unload.mock_calls) == 1