Add hardkernel hardware integration (#72489)

* Add hardkernel hardware integration

* Remove debug prints

* Improve tests

* Improve test coverage

tests/components/hardkernel/test_config_flow.py

@@ -0,0 +1,58 @@
+"""Test the Hardkernel config flow."""
+from unittest.mock import patch
+
+from homeassistant.components.hardkernel.const import DOMAIN
+from homeassistant.core import HomeAssistant
+from homeassistant.data_entry_flow import RESULT_TYPE_ABORT, RESULT_TYPE_CREATE_ENTRY
+
+from tests.common import MockConfigEntry, MockModule, mock_integration
+
+
+async def test_config_flow(hass: HomeAssistant) -> None:
+    """Test the config flow."""
+    mock_integration(hass, MockModule("hassio"))
+
+    with patch(
+        "homeassistant.components.hardkernel.async_setup_entry",
+        return_value=True,
+    ) as mock_setup_entry:
+        result = await hass.config_entries.flow.async_init(
+            DOMAIN, context={"source": "system"}
+        )
+
+    assert result["type"] == RESULT_TYPE_CREATE_ENTRY
+    assert result["title"] == "Hardkernel"
+    assert result["data"] == {}
+    assert result["options"] == {}
+    assert len(mock_setup_entry.mock_calls) == 1
+
+    config_entry = hass.config_entries.async_entries(DOMAIN)[0]
+    assert config_entry.data == {}
+    assert config_entry.options == {}
+    assert config_entry.title == "Hardkernel"
+
+
+async def test_config_flow_single_entry(hass: HomeAssistant) -> None:
+    """Test only a single entry is allowed."""
+    mock_integration(hass, MockModule("hassio"))
+
+    # Setup the config entry
+    config_entry = MockConfigEntry(
+        data={},
+        domain=DOMAIN,
+        options={},
+        title="Hardkernel",
+    )
+    config_entry.add_to_hass(hass)
+
+    with patch(
+        "homeassistant.components.hardkernel.async_setup_entry",
+        return_value=True,
+    ) as mock_setup_entry:
+        result = await hass.config_entries.flow.async_init(
+            DOMAIN, context={"source": "system"}
+        )
+
+    assert result["type"] == RESULT_TYPE_ABORT
+    assert result["reason"] == "single_instance_allowed"
+    mock_setup_entry.assert_not_called()