[host] Build natively with ninja instead of PlatformIO (#19214)

Co-authored-by: J. Nick Koston <nick@home-assistant.io>

tests/unit_tests/components/host/test_init.py

@@ -0,0 +1,86 @@
+"""Tests for the host platform's native-toolchain wiring."""
+
+from __future__ import annotations
+
+import asyncio
+from unittest.mock import patch
+
+import pytest
+
+from esphome.components import host
+import esphome.config_validation as cv
+from esphome.const import (
+    KEY_CORE,
+    KEY_TARGET_FRAMEWORK,
+    KEY_TARGET_PLATFORM,
+    PLATFORM_HOST,
+    Toolchain,
+)
+from esphome.core import CORE, EsphomeError
+
+
+@pytest.fixture(autouse=True)
+def _core_data() -> None:
+    CORE.data[KEY_CORE] = {}
+
+
+def test_schema_resolves_the_host_toolchain() -> None:
+    """The host serves exactly one toolchain; it is picked without config."""
+    config = host.CONFIG_SCHEMA({})
+    assert CORE.toolchain is Toolchain.HOST
+    assert CORE.using_native_toolchain
+    assert CORE.data[KEY_CORE][KEY_TARGET_PLATFORM] == PLATFORM_HOST
+    assert CORE.data[KEY_CORE][KEY_TARGET_FRAMEWORK] == "host"
+    assert "mac_address" in config
+
+
+def test_schema_rejects_the_platformio_toolchain() -> None:
+    """There is no PlatformIO backend left to honor --toolchain platformio."""
+    CORE.toolchain = Toolchain.PLATFORMIO
+    with pytest.raises(cv.Invalid, match="Unsupported toolchain 'platformio' for host"):
+        host.CONFIG_SCHEMA({})
+
+
+def test_to_code_configures_the_native_build() -> None:
+    config = host.CONFIG_SCHEMA({"mac_address": "AA:BB:CC:DD:EE:FF"})
+    asyncio.run(host.to_code(config))
+    assert "-DUSE_HOST" in CORE.build_flags
+    # The standard travels through cpp_standard, not a -std= build flag,
+    # so the generator can keep it off the C compile line
+    assert CORE.cpp_standard == "gnu++20"
+    assert not any(flag.startswith("-std=") for flag in CORE.build_flags)
+    assert not CORE.platformio_options
+    define_names = {define.name for define in CORE.defines}
+    assert {"ESPHOME_BOARD", "ESPHOME_VARIANT", "USE_ESPHOME_HOST_MAC_ADDRESS"} <= (
+        define_names
+    )
+
+
+def test_run_compile_hook_claims_the_build() -> None:
+    config = {"esphome": {}}
+    with (
+        patch.object(host.sys, "platform", "linux"),
+        patch("esphome.host.toolchain.run_compile", return_value=0) as run,
+    ):
+        assert host.run_compile(object(), config) is True
+    run.assert_called_once_with(config, CORE.verbose)
+
+
+def test_run_compile_hook_raises_on_failure() -> None:
+    with (
+        patch.object(host.sys, "platform", "linux"),
+        patch("esphome.host.toolchain.run_compile", return_value=2),
+        pytest.raises(EsphomeError, match="Host build failed"),
+    ):
+        host.run_compile(object(), {"esphome": {}})
+
+
+def test_run_compile_hook_refuses_windows() -> None:
+    """The host sources use POSIX interfaces; fail before building, by name."""
+    with (
+        patch.object(host.sys, "platform", "win32"),
+        patch("esphome.host.toolchain.run_compile") as run,
+        pytest.raises(EsphomeError, match="does not build on Windows"),
+    ):
+        host.run_compile(object(), {"esphome": {}})
+    run.assert_not_called()