diff --git a/src/file.c b/src/file.c
index 7b91c70..523aa33 100644
--- a/src/file.c
+++ b/src/file.c
@@ -10,8 +10,11 @@
 
 #include <stdlib.h>
 #include <stdint.h>
+#include <limits.h>
 
 #if defined(__GNUC__)
+#define _FILE_OFFSET_BITS_ 64
+
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/stat.h>
@@ -148,7 +151,7 @@ CosmsCoreFileError cosms_core_file_write(const char *path, const char *content,
     if (override) {
         file = open(path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
     } else {
-        file = open(path, O_WRONLY | O_APPEND);
+        file = open(path, O_WRONLY | O_CREAT | O_APPEND, 0644);
     }
 
     if (file == -1) {
@@ -312,4 +315,4 @@ const char *cosms_core_file_error_string(CosmsCoreFileError error) {
         default:
             return NULL;
     }
-}
\ No newline at end of file
+}
diff --git a/tests/test.h b/tests/test.h
index 9827c6a..5b53b4b 100644
--- a/tests/test.h
+++ b/tests/test.h
@@ -10,7 +10,7 @@
 #define COSMS_CORE_TEST_SUCCESS(test_name) printf("[+] test %s completed successfully!\n", test_name);
 #define COSMS_CORE_TEST_FAIL(test_name, error) printf("[-] test %s failed with error: %s\n", test_name, error)
 
-inline bool cosms_core_test_assert(const char *test_name, bool expression, const char *error_message) {
+static inline bool cosms_core_test_assert(const char *test_name, bool expression, const char *error_message) {
     if (!expression) {
         printf("[-] test %s failed with error: %s\n", test_name, error_message);
         return false;
@@ -19,4 +19,4 @@ inline bool cosms_core_test_assert(const char *test_name, bool expression, const
     return true;
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/tests/unit/file.c b/tests/unit/file.c
index 5c4beb5..9e3276e 100644
--- a/tests/unit/file.c
+++ b/tests/unit/file.c
@@ -6,7 +6,7 @@
 #include <string.h>
 #include <stdlib.h>
 
-void cosms_core_file_read_test() {
+void cosms_core_file_read_test(void) {
     COSMS_CORE_TEST_HEADER("file read");
 
     const char *current_test_name = "reading small file";
@@ -64,7 +64,7 @@ void cosms_core_file_read_test() {
     free(file_buffer);
 }
 
-void cosms_core_file_write_test() {
+void cosms_core_file_write_test(void) {
     COSMS_CORE_TEST_HEADER("file write");
 
     const char *current_test_name = "writting small file";
@@ -147,7 +147,7 @@ void cosms_core_file_write_test() {
     }
 }
 
-void cosms_core_file_delete_test() {
+void cosms_core_file_delete_test(void) {
     COSMS_CORE_TEST_HEADER("file delete");
 
     const char *current_test_name = "deleting small file";
@@ -189,4 +189,4 @@ void cosms_core_file_delete_test() {
     if (cosms_core_test_assert(current_test_name, error == COSMS_CORE_FILE_NOT_FOUND, cosms_core_file_error_string(error))) {
         COSMS_CORE_TEST_SUCCESS(current_test_name);
     }
-}
\ No newline at end of file
+}