Add Mill config flow (#35136)

* Mill config, wip

* add tests

* fix merge

* update tests

* unique id

* Mill strings

* mill config flow

* mill config flow

* test import

* test import

* req

* ccoverage

* Apply suggestions from code review

Co-authored-by: J. Nick Koston <nick@koston.org>

* style

* Apply suggestions from code review

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

* update strings

* add test

Co-authored-by: J. Nick Koston <nick@koston.org>
Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

tests/components/mill/test_config_flow.py

@@ -0,0 +1,86 @@
+"""Tests for Mill config flow."""
+import pytest
+
+from homeassistant.components.mill.const import DOMAIN
+from homeassistant.const import CONF_PASSWORD, CONF_USERNAME
+
+from tests.async_mock import patch
+from tests.common import MockConfigEntry
+
+
+@pytest.fixture(name="mill_setup", autouse=True)
+def mill_setup_fixture():
+    """Patch mill setup entry."""
+    with patch("homeassistant.components.mill.async_setup_entry", return_value=True):
+        yield
+
+
+async def test_show_config_form(hass):
+    """Test show configuration form."""
+    result = await hass.config_entries.flow.async_init(
+        DOMAIN, context={"source": "user"}
+    )
+
+    assert result["type"] == "form"
+    assert result["step_id"] == "user"
+
+
+async def test_create_entry(hass):
+    """Test create entry from user input."""
+    test_data = {
+        CONF_USERNAME: "user",
+        CONF_PASSWORD: "pswd",
+    }
+
+    with patch("mill.Mill.connect", return_value=True):
+        result = await hass.config_entries.flow.async_init(
+            DOMAIN, context={"source": "user"}, data=test_data
+        )
+
+    assert result["type"] == "create_entry"
+    assert result["title"] == test_data[CONF_USERNAME]
+    assert result["data"] == test_data
+
+
+async def test_flow_entry_already_exists(hass):
+    """Test user input for config_entry that already exists."""
+
+    test_data = {
+        CONF_USERNAME: "user",
+        CONF_PASSWORD: "pswd",
+    }
+
+    first_entry = MockConfigEntry(
+        domain="mill", data=test_data, unique_id=test_data[CONF_USERNAME],
+    )
+    first_entry.add_to_hass(hass)
+
+    with patch("mill.Mill.connect", return_value=True):
+        result = await hass.config_entries.flow.async_init(
+            DOMAIN, context={"source": "user"}, data=test_data
+        )
+
+    assert result["type"] == "abort"
+    assert result["reason"] == "already_configured"
+
+
+async def test_connection_error(hass):
+    """Test connection error."""
+
+    test_data = {
+        CONF_USERNAME: "user",
+        CONF_PASSWORD: "pswd",
+    }
+
+    first_entry = MockConfigEntry(
+        domain="mill", data=test_data, unique_id=test_data[CONF_USERNAME],
+    )
+    first_entry.add_to_hass(hass)
+
+    with patch("mill.Mill.connect", return_value=False):
+        result = await hass.config_entries.flow.async_init(
+            DOMAIN, context={"source": "user"}, data=test_data
+        )
+
+    assert result["type"] == "form"
+    assert result["errors"]["connection_error"] == "connection_error"