feat: Add another delay for the slack test

src/tests/slack_test.py

@@ -49,6 +49,10 @@ class SlackTest(DecisionTest):
         print(colored(f"[SlackTest] The cluster numbers associated with the overwrite file ({overwrite_file_path}) are {overwrite_file_clusters}", "light_grey"))
         overwrite_file_last_cluster: int = self.drive_handle.read_cluster(overwrite_file_clusters[-1])
 
+        self.drive_handle.flush_cache()
+        print(colored("[SlackTest] Waiting 120s for the OS to flush the write cache.", "light_grey"))
+        time.sleep(120)
+
         # analyse the slack space
         (sector_size, sectors_per_cluster, _) = self.drive_handle.get_allocation_unit_sizes()
         half_cluster: int = sector_size * (sectors_per_cluster // 2)