Errata

Error: Compute a specific power of 2: Math.Pow(power, 2)

I was confused here for a while until I realized it was mistake (I didn't look at the solution). I solved the exercise with the assumption that you meant (2, power).

And after looking at the solution, yeah this must be a mistake.

The mock random was causing an issue with the random player method when running tests. Basically, if you run all tests in a sequence, the mock random would effect the RandomPlayer method and make the test fail:
Message: 
Test method GoFishTests.GameControllerTests.TestNextRound threw exception:
System.InvalidOperationException: Sequence contains no elements

Stack Trace: 
ThrowHelper.ThrowNoElementsException()
Enumerable.First[TSource](IEnumerable1 source)
GameState.RandomPlayer(Player currentPlayer) line 40
GameController.ComputerPlayersPlayNextRound() line 66
GameController.NextRound(Player playerToAsk, Values valueToAskFor) line 52
GameControllerTests.TestNextRound() line 31
RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

The AI explained it to me, idk if it was something I was doing wrong or not, but running the test on it's own it passed, but if I run them all back to back it fails. I think somehow the mock random is like setting the random value from one test but not resetting it on that test. So that's why running it on its own works, but running all tests back to back it breaks.

I was so confused for atleast 3 hours trying to figure this out before I went to the AI, and I'm taking a break now, but hopefully I can move forward next time. Putting this here for you though, cause that was not fun lol.

Also, it may just be something I'm doing wrong, so you probably want to just toss this errata submission! (tackle at your own risk, cause I'm making no sense at this point)

Sequence contains no elements comes from this line in GameState.RandomPlayer:

return Players.Where(p => p != currentPlayer)
.Skip(Player.Random.Next(Players.Count() - 1))
.First(); // <-- throws when the sequence is empty

What makes the sequence empty?

Players.Where(p => p != currentPlayer)
With two players (the human and one computer) this yields one element.

Players.Count() – 1
With those same two players the upper-bound passed to Next is 1.

Real System.Random would only ever return 0 when you call Next(1) (because the upper-bound is exclusive), so .Skip(0) would leave the one element in place and .First() would succeed.

Your MockRandom ignores that upper-bound:

public override int Next(int maxValue) => ValueToReturn; // no range check

In GameStateTests.TestRandomPlayer you set ValueToReturn = 1.
Because Player.Random is static, that instance is still in place when
GameControllerTests.TestNextRound runs.
Now Next(1) returns 1, .Skip(1) removes the only opponent, the sequence is empty, and .First() throws the exception that the test reports.

In the class diagram is has "private House house", house is supposed to be static, so this isn't possible right?

I asked chatGPT and it said:
"The diagram shows a field named “private House house” inside GameController. This is incorrect: the House class is declared static, so it cannot be instantiated or stored in a variable. Remove that field from the diagram and any sample code. GameController should refer to the map through House’s static members, for example:

public Location CurrentLocation { get; private set; } = House.Entry;

This eliminates compiler error CS0712 and keeps the diagram consistent with the exercise requirements.

— Errata note provided by ChatGPT"

The instruction says "Add a ; after the closing curly bracket."
but It should say "Add a ; after the closing bracket."

Also, this is a bit redundant because it shows to do this in step 2 on the previous page.

You show a closing comma after the last item in the list. It certainly is not necessary. It may also generate a syntax error.

The solution only shows 6 <RowDefinition/> statements. However, the last label "guacamole" references Grid.Row="6". That is the seventh row. I added another <RowDefinition/> and the code worked. The code on gihub is also wrong.

May have made a mistake but...

Damage = BASE_DAMAGE seems to be superfluous.

Damage is immediately replaced by the next line of code and there are no logic checks to ever retain the default value.

Damage = (int)(Roll * magicMultiplier) + BASE_DAMAGE;