diff --git a/.github/workflows/cmake-multi-platform.yml b/.github/workflows/cmake-multi-platform.yml
index 804b708..f549d96 100644
--- a/.github/workflows/cmake-multi-platform.yml
+++ b/.github/workflows/cmake-multi-platform.yml
@@ -45,7 +45,7 @@ jobs:
             c_compiler: cl
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v3
       with:
         submodules: true
 
diff --git a/test/blackbox/suites/easy/easy_unset.c b/test/blackbox/suites/easy/easy_unset.c
index 1c8b46e..b81b06c 100644
--- a/test/blackbox/suites/easy/easy_unset.c
+++ b/test/blackbox/suites/easy/easy_unset.c
@@ -13,11 +13,10 @@ TEST easy_unset_one(void) {
     get_settings_singleton()->is_backtrack       = false;
     get_settings_singleton()->is_forward_check   = false;
 
-    FILE * fp = fopen(get_settings_singleton()->filepath, "r");
+    FILE * fp = fopen(get_settings_singleton()->filepath, "rb");
     ASSERTm("COULDN'T OPEN FILE", fp);
+    
     Kakuro board = init_kakuro(fp);
-
-    fflush(stdout);
     fclose(fp);
     
     SArray solution = depth_first_search(board);
@@ -43,7 +42,7 @@ TEST easy_unset_two(void) {
     get_settings_singleton()->is_backtrack       = false;
     get_settings_singleton()->is_forward_check   = false;
 
-    FILE * fp = fopen(get_settings_singleton()->filepath, "r");
+    FILE * fp = fopen(get_settings_singleton()->filepath, "rb");
     ASSERTm("COULDN'T OPEN FILE", fp);
 
     Kakuro board = init_kakuro(fp);
@@ -72,7 +71,7 @@ TEST easy_unset_three(void) {
     get_settings_singleton()->is_backtrack       = false;
     get_settings_singleton()->is_forward_check   = false;
 
-    FILE * fp = fopen(get_settings_singleton()->filepath, "r");
+    FILE * fp = fopen(get_settings_singleton()->filepath, "rb");
     ASSERTm("COULDN'T OPEN FILE", fp);
 
     Kakuro board = init_kakuro(fp);
@@ -101,7 +100,7 @@ TEST easy_unset_four(void) {
     get_settings_singleton()->is_backtrack       = false;
     get_settings_singleton()->is_forward_check   = false;
 
-    FILE * fp = fopen(get_settings_singleton()->filepath, "r");
+    FILE * fp = fopen(get_settings_singleton()->filepath, "rb");
     ASSERTm("COULDN'T OPEN FILE", fp);
 
     Kakuro board = init_kakuro(fp);
@@ -130,7 +129,7 @@ TEST easy_unset_five(void) {
     get_settings_singleton()->is_backtrack       = false;
     get_settings_singleton()->is_forward_check   = false;
 
-    FILE * fp = fopen(get_settings_singleton()->filepath, "r");
+    FILE * fp = fopen(get_settings_singleton()->filepath, "rb");
     ASSERTm("COULDN'T OPEN FILE", fp);
 
     Kakuro board = init_kakuro(fp);