diff --git a/days/comp.py b/days/comp.py
index 5f6a507..29576f3 100644
--- a/days/comp.py
+++ b/days/comp.py
@@ -1,4 +1,4 @@
-from typing import List, Tuple
+from typing import List, Tuple, Any
 
 
 class OpcodeComputer():
@@ -42,7 +42,7 @@ class OpcodeComputer():
             pass
         return (int(i[-2:]), a, b, c)
 
-    def process_op(self) -> int:
+    def process_op(self, inp: List[int] = [], outp: List[Any] = []) -> int:
         """Run program code
 
         Args:
@@ -64,10 +64,10 @@ class OpcodeComputer():
                 mem[mem[pc+3]] = a * b
                 pc += 4
             elif cmd == 3:
-                mem[mem[pc+1]] = int(input())
+                mem[mem[pc+1]] = int(inp.pop(0))
                 pc += 2
             elif cmd == 4:
-                print(str(a))
+                outp.append(str(a))
                 pc += 2
             elif cmd == 5:
                 pc = b if a != 0 else pc + 3
@@ -81,11 +81,3 @@ class OpcodeComputer():
                 pc += 4
             cmd = mem[pc]
         return mem[0]
-
-
-def input() -> str:
-    return input()
-
-
-def print(text: str):
-    print(text)
diff --git a/days/day5.py b/days/day5.py
index 37fcfc0..885bd66 100644
--- a/days/day5.py
+++ b/days/day5.py
@@ -10,23 +10,17 @@ class Day5(unittest.TestCase):
             return [int(k) for k in fp.readline().split(',')]
 
     def test_day5a(self):
-        output_val = []
+        outp = []
 
         sut = comp.OpcodeComputer(self.get_code())
-        # replace input() and print() to simulate user behavior
-        comp.input = lambda: 1
-        comp.print = lambda s: output_val.append(s)
 
-        sut.process_op()
-        self.assertEqual(int(output_val[-1]), 8332629)
+        sut.process_op([1], outp)
+        self.assertEqual(int(outp[-1]), 8332629)
 
     def test_day5b(self):
-        output_val = []
+        outp = []
 
         sut = comp.OpcodeComputer(self.get_code())
-        # replace input() and print() to simulate user behavior
-        comp.input = lambda: 5
-        comp.print = lambda s: output_val.append(s)
 
-        sut.process_op()
-        self.assertEqual(int(output_val[-1]), 8805067)
+        sut.process_op([5], outp)
+        self.assertEqual(int(outp[-1]), 8805067)