kunit: add example test case showing off all the expect macros

Currently, these macros are only really documented near the bottom of
https://www.kernel.org/doc/html/latest/dev-tools/kunit/api/test.html#c.KUNIT_FAIL.

E.g. it's likely someone might just not realize that
KUNIT_EXPECT_STREQ() exists and instead use KUNIT_EXPECT_FALSE(strcmp())
or similar.

This can also serve as a basic smoketest that the KUnit assert machinery
still works for all the macros.

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

lib/kunit/kunit-example-test.c

@@ -69,6 +69,47 @@ static void example_mark_skipped_test(struct kunit *test)
 	/* This line should run */
 	kunit_info(test, "You should see this line.");
 }
+
+/*
+ * This test shows off all the types of KUNIT_EXPECT macros.
+ */
+static void example_all_expect_macros_test(struct kunit *test)
+{
+	/* Boolean assertions */
+	KUNIT_EXPECT_TRUE(test, true);
+	KUNIT_EXPECT_FALSE(test, false);
+
+	/* Integer assertions */
+	KUNIT_EXPECT_EQ(test, 1, 1); /* check == */
+	KUNIT_EXPECT_GE(test, 1, 1); /* check >= */
+	KUNIT_EXPECT_LE(test, 1, 1); /* check <= */
+	KUNIT_EXPECT_NE(test, 1, 0); /* check != */
+	KUNIT_EXPECT_GT(test, 1, 0); /* check >  */
+	KUNIT_EXPECT_LT(test, 0, 1); /* check <  */
+
+	/* Pointer assertions */
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, test);
+	KUNIT_EXPECT_PTR_EQ(test, NULL, NULL);
+	KUNIT_EXPECT_PTR_NE(test, test, NULL);
+
+	/* String assertions */
+	KUNIT_EXPECT_STREQ(test, "hi", "hi");
+	KUNIT_EXPECT_STRNEQ(test, "hi", "bye");
+
+	/*
+	 * There are also ASSERT variants of all of the above that abort test
+	 * execution if they fail. Useful for memory allocations, etc.
+	 */
+	KUNIT_ASSERT_GT(test, sizeof(char), 0);
+
+	/*
+	 * There are also _MSG variants of all of the above that let you include
+	 * additional text on failure.
+	 */
+	KUNIT_EXPECT_GT_MSG(test, sizeof(int), 0, "Your ints are 0-bit?!");
+	KUNIT_ASSERT_GT_MSG(test, sizeof(int), 0, "Your ints are 0-bit?!");
+}
+
 /*
  * Here we make a list of all the test cases we want to add to the test suite
  * below.
@@ -83,6 +124,7 @@ static struct kunit_case example_test_cases[] = {
 	KUNIT_CASE(example_simple_test),
 	KUNIT_CASE(example_skip_test),
 	KUNIT_CASE(example_mark_skipped_test),
+	KUNIT_CASE(example_all_expect_macros_test),
 	{}
 };