Add success test for loan eligibility

tests/test_checkLoanEligibility.c

@@ -0,0 +1,36 @@
+#ifdef TEST
+
+#include "unity.h"
+#include "checkLoanEligibility.h"
+
+void setUp(void)
+{
+}
+
+void tearDown(void)
+{
+}
+
+void test_checkLoanEligibilitySuccess(void) {
+
+    /* Arrange */
+
+   int user_id[3]   = {1234, 1327, 1666}; // user_ids from file for testing
+
+   bool result[3];
+
+   /* Act */
+   
+   for (int i = 0; i < 3; i++) {
+        result[i] = checkLoanEligibility(user_id[i]);
+    }   
+
+    /* Assert */
+    
+    for (int i = 0; i < 3; i++) {
+        TEST_ASSERT_TRUE(result[i]);     // Pass if user_id is found in the file
+    }
+}
+
+
+#endif // TEST