diff --git a/src/utils/helpers.py b/src/utils/helpers.py
index 0e7080d..89a8468 100644
--- a/src/utils/helpers.py
+++ b/src/utils/helpers.py
@@ -35,17 +35,19 @@ def time_conversion(
     Returns:
         float: The time in the target unit.
     """
+    # Same unit, no conversion needed
     if unit == target_unit:
         return time
 
     units = ["s", "ms", "us", "ns", "ps"]
 
-    # target_unit must be a SI unit
-    assert target_unit in units
+    assert target_unit in units, "Target unit must be a SI unit"
 
     # Convert dt (device-dependent time) to SI unit
     if unit == "dt":
-        assert dt is not None
+        assert (
+            dt is not None
+        ), "If the target unit is dt, the time of 1dt must be provided"
         time *= dt
         unit = "s"
 
diff --git a/tests/utils/test_helpers.py b/tests/utils/test_helpers.py
new file mode 100644
index 0000000..295f756
--- /dev/null
+++ b/tests/utils/test_helpers.py
@@ -0,0 +1,25 @@
+from pytest import approx, raises
+from src.utils.helpers import time_conversion
+
+
+def test_time_conversion():
+    assert time_conversion(1, "s", "s") == 1
+    assert time_conversion(5, "s", "ms") == 5000
+    assert time_conversion(2, "s", "us") == 2000000
+    assert time_conversion(3, "s", "ns") == 3000000000
+    assert time_conversion(2.4, "ms", "s") == approx(0.0024)
+    assert time_conversion(9.1, "ms", "us") == 9100
+    assert time_conversion(7.8, "ms", "ns") == 7800000
+    assert time_conversion(3, "dt", "s", dt=1.5) == approx(4.5)
+    assert time_conversion(4, "dt", "ms", dt=2) == 8000
+    assert time_conversion(3, "dt", "dt", dt=1) == 3
+
+
+def test_time_conversion_errors():
+    with raises(Exception) as e_info:
+        time_conversion(1, "s", "dt", dt=5)
+    assert e_info.match("Target unit must be a SI unit")
+
+    with raises(Exception) as e_info:
+        time_conversion(1, "dt", "s")
+    assert e_info.match("dt must be provided")