diff --git a/ci/requirements_dev.txt b/ci/requirements_dev.txt
index 92ec384..9589545 100644
--- a/ci/requirements_dev.txt
+++ b/ci/requirements_dev.txt
@@ -10,3 +10,4 @@ mysql-connector-python==8.0.28
 ctd==1.1.1 #python-ctd
 seawater==3.3.4
 #geomag cmweis github version... part of package
+pytest
\ No newline at end of file
diff --git a/src/EcoFOCIpy/epic/EPIC_timeconvert.py b/src/EcoFOCIpy/epic/EPIC_timeconvert.py
index 42b151d..3d76636 100644
--- a/src/EcoFOCIpy/epic/EPIC_timeconvert.py
+++ b/src/EcoFOCIpy/epic/EPIC_timeconvert.py
@@ -87,10 +87,10 @@ def EPIC2Datetime( timeword_1, timeword_2):
     ref_time_dt = datetime.datetime(1968, 5, 23)
     ref_time_epic = 2440000
 
-    delta_days = [x - ref_time_epic for x in timeword_1]
-    delta_seconds = [x/1000 for x in timeword_2]
+    delta_days = timeword_1 - ref_time_epic
+    delta_seconds = timeword_2/1000
     
-    epic_dt = [ref_time_dt + datetime.timedelta(a,c) for a,c in zip(delta_days,delta_seconds)]
+    epic_dt = [ref_time_dt + datetime.timedelta(int(a),int(c)) for a,c in zip(delta_days,delta_seconds)]
 
     return(epic_dt)
 
@@ -163,31 +163,5 @@ def Datetime2EPIC(epic_dt):
 def main():
     pass
 
-def test_1d():
-    testdate = EPIC2Datetime([2440000,],[43200000+3600*1000,])
-    print(f"\n{testdate}\n")
-    for time_format in ['days','hours','seconds']:
-        time_since_str = time_format + ' since 1900-1-1'
-        print(f"{testdate}:value \n{time_since_str}:units\n")
-
-def test_2d():
-    testdate = EPIC2Datetime([2440000,2450000],[43200000,0])
-    print(f"\n{testdate}\n")
-    for time_format in ['days','hours','seconds']:
-        time_since_str = time_format + ' since 1900-1-1'
-        print(f"{testdate}:value \n{time_since_str}:units\n")
-
-def test_1d_EPIC():
-    testdate = EPIC2Datetime([2440000,],[43200000+3600*1000,])
-    print(f'{testdate}')
-    testdate1 = Datetime2EPIC(testdate)
-    print(f'{testdate1}')
-
-def test_2d_EPIC():
-    testdate = EPIC2Datetime([2440000,2450000],[43200000,0])
-    print(f'{testdate}')
-    testdate1 = Datetime2EPIC(testdate)
-    print(f'{testdate1}')
-
 if __name__ == "__main__":
     main()
diff --git a/tests/test_epic.py b/tests/test_epic.py
new file mode 100644
index 0000000..4741d56
--- /dev/null
+++ b/tests/test_epic.py
@@ -0,0 +1,23 @@
+import datetime
+
+import pytest
+from EcoFOCIpy.epic import EPIC_timeconvert as EPIC
+
+
+class TestClassEPICTime:
+    def test_1d(self):
+        testdate = EPIC.EPIC2Datetime([2440000,],[43200000+3600*1000,])
+        assert testdate == [datetime.datetime(1968, 5, 23, 13, 0)]
+
+    def test_2d(self):
+        testdate = EPIC.EPIC2Datetime([2440000,2450000],[43200000,0])
+        assert testdate == [datetime.datetime(1968, 5, 23, 12, 0), datetime.datetime(1995, 10, 9, 0, 0)]
+
+    def test_1d_EPIC(self):
+        testdate = EPIC.Datetime2EPIC(EPIC.EPIC2Datetime([2440000,],[43200000+3600*1000,]))
+        assert testdate == ([2440000], [46800000])
+
+    def test_2d_EPIC(self):
+        testdate = EPIC.Datetime2EPIC(EPIC.EPIC2Datetime([2440000,2450000],[43200000,0]))
+        assert testdate == ([2440000,2450000],[43200000,0])
+