[PATCH v5 13/15] kunit: uapi: Add example for UAPI tests

[Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>]

Extend the example to show how to run a userspace executable.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
Reviewed-by: David Gow <davidgow@xxxxxxxxxx>
---
 MAINTAINERS                    |  1 +
 lib/kunit/Makefile             | 10 ++++++++++
 lib/kunit/kunit-example-test.c | 15 +++++++++++++++
 lib/kunit/kunit-example-uapi.c | 22 ++++++++++++++++++++++
 4 files changed, 48 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 0f60501c6de570723123b24eb930d15f1bd956eb..b1405f0a0e638d1654d9dc9e51d784ddc838cf5b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13544,6 +13544,7 @@ KUNIT UAPI TESTING FRAMEWORK (in addition to KERNEL UNIT TESTING FRAMEWORK)
 M:	Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
 S:	Maintained
 F:	include/kunit/uapi.h
+F:	lib/kunit/kunit-example-uapi.c
 F:	lib/kunit/kunit-uapi.c
 
 KVM PARAVIRT (KVM/paravirt)
diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile
index 6059621a2d32c8e7384acda59793f05826af8c81..2434470e998525e5667ebc207d11659835b5e888 100644
--- a/lib/kunit/Makefile
+++ b/lib/kunit/Makefile
@@ -1,3 +1,5 @@
+include $(srctree)/init/Makefile.nolibc
+
 obj-$(CONFIG_KUNIT) +=			kunit.o
 
 kunit-objs +=				test.o \
@@ -31,3 +33,11 @@ obj-$(CONFIG_KUNIT_TEST) +=		assert_test.o
 endif
 
 obj-$(CONFIG_KUNIT_EXAMPLE_TEST) +=	kunit-example-test.o
+
+userprogs +=				kunit-example-uapi
+kunit-example-uapi-userccflags :=	-static $(NOLIBC_USERCFLAGS)
+
+ifdef CONFIG_KUNIT_UAPI
+CFLAGS_kunit-example-test.o :=		-Wa,-I$(obj)
+$(obj)/kunit-example-test.o: $(obj)/kunit-example-uapi
+endif
diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c
index 3056d6bc705d0a8f196f0f4412e679dbb0e03114..0c5e1e59f9358b84aee2621e342d824a2f99f9aa 100644
--- a/lib/kunit/kunit-example-test.c
+++ b/lib/kunit/kunit-example-test.c
@@ -8,6 +8,7 @@
 
 #include <kunit/test.h>
 #include <kunit/static_stub.h>
+#include <kunit/uapi.h>
 
 /*
  * This is the most fundamental element of KUnit, the test case. A test case
@@ -277,6 +278,19 @@ static void example_slow_test(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, 1 + 1, 2);
 }
 
+/*
+ * This test shows the usage of UAPI tests.
+ */
+static void example_uapi_test(struct kunit *test)
+{
+	KUNIT_UAPI_EMBED_BLOB(kunit_example_uapi, "kunit-example-uapi");
+
+	if (IS_ENABLED(CONFIG_KUNIT_UAPI))
+		kunit_uapi_run_kselftest(test, &kunit_example_uapi);
+	else
+		kunit_skip(test, "CONFIG_KUNIT_UAPI is not enabled");
+}
+
 /*
  * Here we make a list of all the test cases we want to add to the test suite
  * below.
@@ -297,6 +311,7 @@ static struct kunit_case example_test_cases[] = {
 	KUNIT_CASE(example_priv_test),
 	KUNIT_CASE_PARAM(example_params_test, example_gen_params),
 	KUNIT_CASE_SLOW(example_slow_test),
+	KUNIT_CASE(example_uapi_test),
 	{}
 };
 
diff --git a/lib/kunit/kunit-example-uapi.c b/lib/kunit/kunit-example-uapi.c
new file mode 100644
index 0000000000000000000000000000000000000000..4ce657050dd4a576632a41ca0309c4cb5134ce14
--- /dev/null
+++ b/lib/kunit/kunit-example-uapi.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KUnit Userspace example test.
+ *
+ * Copyright (C) 2025, Linutronix GmbH.
+ * Author: Thomas Weißschuh <thomas.weissschuh@xxxxxxxxxxxxx>
+ *
+ * This is *userspace* code.
+ */
+
+#include "../../tools/testing/selftests/kselftest.h"
+
+int main(void)
+{
+	ksft_print_header();
+	ksft_set_plan(4);
+	ksft_test_result_pass("userspace test 1\n");
+	ksft_test_result_pass("userspace test 2\n");
+	ksft_test_result_skip("userspace test 3: some reason\n");
+	ksft_test_result_pass("userspace test 4\n");
+	ksft_finished();
+}

-- 
2.50.0