[PATCH i-g-t 1/1] tests/intel/xe_sysfs_scheduler: Add invalid string test for engine sysfs properties

[replace_with Sobin Thomas <sobin.thomas@intel.com>]

From: Sobin Thomas <sobin.thomas@intel.com>

This test validates that invalid string inputs are correctly rejected
by engine sysfs write. It ensures that the property values remain
unchanged when invalid inputs are provided.

v2: Added error check for return values for igt_sysfs_scanf and
igt_sysfs_printf. Removed the changes for fault injection in
tests/intel/xe_fault_injection.c

v1: Initial changes for checking error string.

Signed-off-by: Sobin Thomas <sobin.thomas@intel.com>
---
 tests/intel/xe_sysfs_scheduler.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tests/intel/xe_sysfs_scheduler.c b/tests/intel/xe_sysfs_scheduler.c
index 4fc764f82..594c51d44 100644
--- a/tests/intel/xe_sysfs_scheduler.c
+++ b/tests/intel/xe_sysfs_scheduler.c
@@ -10,6 +10,11 @@
  * Sub-category: SysMan tests
  * Functionality: scheduler control interface
  *
+ * SUBTEST: %s-invalid-string
+ * Description: Test to check if %s arg[1] schedule parameter checks for
+ * min max values.
+ * Test category: Negative string test
+ *
  * SUBTEST: %s-invalid
  * Description: Test to check if %s arg[1] schedule parameter rejects any
  *		unrepresentable intervals.
@@ -121,6 +126,29 @@ static void test_min_max(int xe, int engine, const char **property,
 	igt_assert_eq(set, default_max);
 }
 
+static void test_invalid_string(int xe, int engine, const char **property,
+				uint16_t class, int gt)
+{
+	unsigned int saved, set;
+	char invalid_input[] = "999abc";
+
+	for (int i = 0; i < 3; i++) {
+		igt_assert(igt_sysfs_scanf(engine, property[i], "%u", &saved) == 1);
+		igt_info("Initial %s: %u\n", property[i], saved);
+		if (igt_sysfs_printf(engine, property[i], "%s", invalid_input) > 0) {
+			igt_critical("invalid value %s can be set to property %s\n",
+					invalid_input, property[i]);
+			continue;
+		}
+
+		igt_assert(igt_sysfs_scanf(engine, property[i], "%u", &set) == 0);
+
+		//Check if the values are unchanged.
+		igt_assert_eq(set, saved);
+	}
+}
+
+
 #define MAX_GTS 8
 igt_main
 {
@@ -130,6 +158,7 @@ igt_main
 	} tests[] = {
 		{ "invalid", test_invalid },
 		{ "min-max", test_min_max },
+		{ "invalid-string", test_invalid_string },
 		{ }
 	};
 
-- 
2.34.1