diff --git a/src/machine.rs b/src/machine.rs
index 2bc581d..0ee94c4 100644
--- a/src/machine.rs
+++ b/src/machine.rs
@@ -335,48 +335,3 @@ fn dec_x_test() {
     assert_eq!(machine.registers.status.contains(PS_NEGATIVE), true);
     assert_eq!(machine.registers.status.contains(PS_OVERFLOW), false);
 }
-
-#[test]
-fn dec_x_test() {
-    let mut machine = Machine::new();
-
-    machine.dec_x();
-    assert_eq!(machine.registers.index_x, -1);
-    assert_eq!(machine.registers.status.contains(ps_carry),    false);
-    assert_eq!(machine.registers.status.contains(ps_zero),     false);
-    assert_eq!(machine.registers.status.contains(ps_negative), true);
-    assert_eq!(machine.registers.status.contains(ps_overflow), false);
-
-    machine.dec_x();
-    assert_eq!(machine.registers.index_x, -2);
-    assert_eq!(machine.registers.status.contains(ps_carry),    false);
-    assert_eq!(machine.registers.status.contains(ps_zero),     false);
-    assert_eq!(machine.registers.status.contains(ps_negative), true);
-    assert_eq!(machine.registers.status.contains(ps_overflow), false);
-
-    machine.load_x_register(5);
-    machine.dec_x();
-    assert_eq!(machine.registers.index_x, 4);
-    assert_eq!(machine.registers.status.contains(ps_carry),    false);
-    assert_eq!(machine.registers.status.contains(ps_zero),     false);
-    assert_eq!(machine.registers.status.contains(ps_negative), false);
-    assert_eq!(machine.registers.status.contains(ps_overflow), false);
-
-    machine.dec_x();
-    machine.dec_x();
-    machine.dec_x();
-    machine.dec_x();
-
-    assert_eq!(machine.registers.index_x, 0);
-    assert_eq!(machine.registers.status.contains(ps_carry),    false);
-    assert_eq!(machine.registers.status.contains(ps_zero),     true);
-    assert_eq!(machine.registers.status.contains(ps_negative), false);
-    assert_eq!(machine.registers.status.contains(ps_overflow), false);
-
-    machine.dec_x();
-    assert_eq!(machine.registers.index_x, -1);
-    assert_eq!(machine.registers.status.contains(ps_carry),    false);
-    assert_eq!(machine.registers.status.contains(ps_zero),     false);
-    assert_eq!(machine.registers.status.contains(ps_negative), true);
-    assert_eq!(machine.registers.status.contains(ps_overflow), false);
-}