diff --git a/python/5/test_day5.py b/python/5/test_day5.py
new file mode 100644
index 0000000..ec1ef59
--- /dev/null
+++ b/python/5/test_day5.py
@@ -0,0 +1,21 @@
+from day5 import run_intcode, decode_code, part1
+
+
+def test_new_opcodes():
+    assert run_intcode([3, 0, 4, 0, 99], input=33) == ([33, 0, 4, 0, 99], [33])
+
+
+def test_parameter_mode():
+    assert run_intcode([1002, 4, 3, 4, 33], input=None) == ([1002, 4, 3, 4, 99], [])
+
+
+def test_negative_case():
+    assert run_intcode([1101, 100, -1, 4, 0], input=42) == ([1101, 100, -1, 4, 99], [])
+
+
+def test_decode_code():
+    assert decode_code(1002) == (10, 2)
+
+
+def test_part1():
+    assert part1() == [0, 0, 0, 0, 0, 0, 0, 0, 0, 7286649]