diff --git a/cwl_airflow/utilities/helpers.py b/cwl_airflow/utilities/helpers.py
index db14405..1e106cd 100644
--- a/cwl_airflow/utilities/helpers.py
+++ b/cwl_airflow/utilities/helpers.py
@@ -30,7 +30,7 @@ def yield_file_content(location):
                 yield line.strip()
 
 
-def get_compressed(data_str, reset_position=None, mtime=None):
+def get_compressed(data_str, reset_position=None):
     """
     Converts character string "data_str" as "utf-8" into bytes ("utf-8"
     is default encoding for Python3 string). Encoded bytes are then being
@@ -43,10 +43,7 @@ def get_compressed(data_str, reset_position=None, mtime=None):
     failed to dump it with json, assume that "data_str" was a stream, from
     where we read content either as "utf-8" or as bytes, depending on the mode
     that the file was opened with. In this case if "reset_position" is true,
-    reset to the beginning of the file. mtime is an optional numeric timestamp
-    to be written to the last modification time field in the stream when
-    compressing. If omitted or None, the current time is used. We need this
-    argument only for reproducible results in unit tests.
+    reset to the beginning of the file.
     """
 
     reset_position = True if reset_position is None else reset_position
@@ -64,7 +61,7 @@ def get_compressed(data_str, reset_position=None, mtime=None):
             else:                                               # file was opened in a text mode and need to be "utf-8" encoded
                 data_str_utf = data_str.read().encode("utf-8")
     return base64.b64encode(
-        gzip.compress(data=data_str_utf, mtime=mtime)
+        gzip.compress(data=data_str_utf)
     ).decode("utf-8")
 
 
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index 8658523..608e06e 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -3,6 +3,7 @@
 import tempfile
 import zlib
 import binascii
+import time
 
 from os import environ, path, listdir
 
@@ -62,80 +63,77 @@ def test_get_md5_sum(location, control_md5sum):
 
 
 @pytest.mark.parametrize(
-    "raw_data, control_data, mtime",
+    "raw_data, control_data",
     [
         (
             "hello world",
-            "H4sIAEi9118C/8tIzcnJVyjPL8pJAQCFEUoNCwAAAA==",
-            1607974216.711175
+            "H4sIAEi9118C/8tIzcnJVyjPL8pJAQCFEUoNCwAAAA=="
         ),
         (
             {"data": "hello world"},
-            "H4sIAEi9118C/6tWSkksSVSyUlDKSM3JyVcozy/KSVGqBQAnYva2FwAAAA==",
-            1607974216.711175
+            "H4sIAEi9118C/6tWSkksSVSyUlDKSM3JyVcozy/KSVGqBQAnYva2FwAAAA=="
         )
     ]
 )
-def test_get_compressed(raw_data, control_data, mtime):
-    compressed_data = get_compressed(raw_data, mtime=mtime)
+def test_get_compressed(raw_data, control_data, monkeypatch):
+    monkeypatch.setattr(time, "time", lambda : 1607974216.711175)
+    compressed_data = get_compressed(raw_data)
     assert control_data == compressed_data, \
         "Failed to compress data"
 
 
 @pytest.mark.parametrize(
-    "location, control_data, reset_position, mtime",
+    "location, control_data, reset_position",
     [
         (
             path.join(DATA_FOLDER, "jobs", "bam-bedgraph-bigwig.json"),
 "H4sIAEi9118C/62NTQrCQAyF93OKkrVMW3DlAbxGiNNoB+aPJoJQevdOR0Hcm+X3vby3mq\
 4e3Cji3QeGS7c20qgLJFIRXA91+oqQHanP6XDW9j6Vp0rv5uWM4zBgpFJ4woVpEluroX1u7\
 wKosRwxcHro/JdRTBT5U2j1pb9z4qhNjGYzO393NUbuAAAA",
-            None,
-            1607974216.711175
+            None
         ),
         (
             path.join(DATA_FOLDER, "jobs", "bam-bedgraph-bigwig.json"),
 "H4sIAEi9118C/5WNSwrCQBBE93OKptcyScBVDuA1mnYymoH5kW5BkNxdkxiCS2tbVe8BbE\
 EXWQR7wEuIHk8G9iIWxxpKXjprm5DrQ6Vx43Smrm0pca1+oMnzIPbKCdfnvAHwMyuJos93H\
 em2kHt4Hez/pZQ5+S/Q6lN/deJ4VXRmNm9wvXwe2gAAAA==",
-            False,
-            1607974216.711175
+            False
         )
     ]
 )
-def test_get_compressed_from_text_stream(location, control_data, reset_position, mtime):
+def test_get_compressed_from_text_stream(location, control_data, reset_position, monkeypatch):
+    monkeypatch.setattr(time, "time", lambda : 1607974216.711175)
     with open(location, "r") as input_stream:
         input_stream.read(20)  # change position while reading from file
-        compressed_data = get_compressed(input_stream, reset_position, mtime)
+        compressed_data = get_compressed(input_stream, reset_position)
     assert control_data == compressed_data, \
         "Failed to compress data"
 
 
 @pytest.mark.parametrize(
-    "location, control_data, reset_position, mtime",
+    "location, control_data, reset_position",
     [
         (
             path.join(DATA_FOLDER, "jobs", "bam-bedgraph-bigwig.json"),
 "H4sIAEi9118C/62NTQrCQAyF93OKkrVMW3DlAbxGiNNoB+aPJoJQevdOR0Hcm+X3vby3mq\
 4e3Cji3QeGS7c20qgLJFIRXA91+oqQHanP6XDW9j6Vp0rv5uWM4zBgpFJ4woVpEluroX1u7\
 wKosRwxcHro/JdRTBT5U2j1pb9z4qhNjGYzO393NUbuAAAA",
-            None,
-            1607974216.711175
+            None
         ),
         (
             path.join(DATA_FOLDER, "jobs", "bam-bedgraph-bigwig.json"),
 "FH4sIAEi9118C/5WNSwrCQBBE93OKptcyScBVDuA1mnYymoH5kW5BkNxdkxiCS2tbVe8Bb\
 EEXWQR7wEuIHk8G9iIWxxpKXjprm5DrQ6Vx43Smrm0pca1+oMnzIPbKCdfnvAHwMyuJos93\
 Hem2kHt4Hez/pZQ5+S/Q6lN/deJ4VXRmNm9wvXwe2gAAAA==",
-            False,
-            1607974216.711175
+            False
         )
     ]
 )
-def test_get_compressed_from_binary_stream(location, control_data, reset_position, mtime):
+def test_get_compressed_from_binary_stream(location, control_data, reset_position, monkeypatch):
+    monkeypatch.setattr(time, "time", lambda : 1607974216.711175)
     with open(location, "rb") as input_stream:
         input_stream.read(20)  # change position while reading from file
-        compressed_data = get_compressed(input_stream, reset_position, mtime)
+        compressed_data = get_compressed(input_stream, reset_position)
     assert control_data == compressed_data, \
         "Failed to compress data"