Imitate reproducing test as closely as possible

Signed-off-by: mulhern <amulhern@redhat.com>

Author: mulkieran

stratisd_cert.py

@@ -1046,16 +1046,18 @@ def test_filesystem_mount_and_write(self):
             os.path.join("/", "dev", "stratis", pool_name, fs_name)
         )
 
-        subprocess.check_call(
-            [
-                "dd",
-                "if=/dev/urandom",
-                f'of={os.path.join(mountpoint, "file1")}',
-                "bs=4096",
-                "count=256",
-                "conv=fsync",
-            ]
-        )
+        for seek in range(7):
+            subprocess.check_call(
+                [
+                    "dd",
+                    "if=/dev/urandom",
+                    f'of={os.path.join(mountpoint, "file1")}',
+                    "bs=4096",
+                    "count=32",
+                    f"seek={seek*32}",
+                    "conv=fsync",
+                ]
+            )
 
     def test_get_report(self):
         """