Question Why I cannot store InputSystem.AddDevice<Keyboard>() into SetUp when testing?

This throws a Null Exception

Code (CSharp):

1. private InputListener inputListener;
2. private Keyboard virtualKeyboard;
3.  
4. [UnitySetUp]
5. public IEnumerator Init()
6. {
7.     inputListener = new GameObject("Input listener").AddComponent<InputListener>();
8.     yield return inputListener.LoadBattleActions();
9.    
10.     virtualKeyboard = InputSystem.AddDevice<Keyboard>();
11. }
12.  
13. [UnityTest]
14. public IEnumerator InputListener_WhenRunningBattleActions_TriggerCorrectEvents()
15. {
16.     // Arrange
17.  
18.     // Act
19.     Press(virtualKeyboard.wKey);
20.  
21.     // Assert
22.     yield return null;
23. }

And this does not

Code (CSharp):

1. private InputListener inputListener;
2. private Keyboard virtualKeyboard;
3.  
4. [UnitySetUp]
5. public IEnumerator Init()
6. {
7.     inputListener = new GameObject("Input listener").AddComponent<InputListener>();
8.     yield return inputListener.LoadBattleActions();
9.    
10. }
11.  
12. [UnityTest]
13. public IEnumerator InputListener_WhenRunningBattleActions_TriggerCorrectEvents()
14. {
15.     // Arrange
16.     virtualKeyboard = InputSystem.AddDevice<Keyboard>();
17.  
18.     // Act
19.     Press(virtualKeyboard.wKey);
20.  
21.     // Assert
22.     yield return null;
23. }

Why?