test: Add some tests for kconfig.h

The macros in this file are a little confusing and we currently have no
tests to check that they work as expected.

Add some tests which check the macros in C code. Add a few tests which
check that the build errors are generated correctly too, using buildman's
-a option.

Signed-off-by: Simon Glass <sjg@chromium.org>

test/py/tests/test_kconfig.py

@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0
+# Copyright 2022 Google LLC
+# Written by Simon Glass <sjg@chromium.org>
+
+import pytest
+
+import u_boot_utils as util
+
+# This is needed for Azure, since the default '..' directory is not writeable
+TMPDIR = '/tmp/test_kconfig'
+
+@pytest.mark.slow
+@pytest.mark.boardspec('sandbox')
+def test_kconfig(u_boot_console):
+    """Test build failures when IF_ENABLED_INT() option is not enabled"""
+    cons = u_boot_console
+
+    # This detects build errors in test/lib/kconfig.c
+    out = util.run_and_log(
+        cons, ['./tools/buildman/buildman', '-m', '--board', 'sandbox',
+               '-a', 'TEST_KCONFIG', '-o', TMPDIR], ignore_errors=True)
+    assert 'invalid_use_of_IF_ENABLED_INT' in out
+    assert 'invalid_use_of_CONFIG_IF_ENABLED_INT' in out
+
+@pytest.mark.slow
+@pytest.mark.boardspec('sandbox_spl')
+def test_kconfig_spl(u_boot_console):
+    """Test build failures when IF_ENABLED_INT() option is not enabled"""
+    cons = u_boot_console
+
+    # This detects build errors in test/lib/kconfig_spl.c
+    out = util.run_and_log(
+        cons, ['./tools/buildman/buildman', '-m', '--board', 'sandbox_spl',
+               '-a', 'TEST_KCONFIG', '-o', TMPDIR], ignore_errors=True)
+    assert 'invalid_use_of_IF_ENABLED_INT' in out
+
+    # There is no CONFIG_SPL_TEST_KCONFIG, so the CONFIG_IF_ENABLED_INT()
+    # line should not generate an error
+    assert 'invalid_use_of_CONFIG_IF_ENABLED_INT' not in out