Already mentioned in description and initial solution setup's comment

Expect_error takes an optional message we're expecting and a block to run which we expect to raise an error:

Test.expect_error(optional_message_if_any) { call to test }

So, we can check for popping off an empty stack raising an error (which we don't know the message for):

Test.expect_error { Magic.spell_stack }

Or for pushing a sorcery spell when there's already spells on the stack

Test.assert_equals(Magic.spell_stack({'name' => 'Enervate', 'type' => 'sorcery' }), 1)
Test.expect_error { Magic.spell_stack({ 'name' => 'Enervate', 'type' => 'sorcery' }) }

It looks like it's been decided the other way...

Not an issue, but a suggestion.

Not an issue.

Duplicate.

.

Fixed.

Dup.

Or maybe you didn't refresh after the tests were updated.

Closing.

Hilary the first example is enough. Just look more closely. Hint it starts with uniq.

Yes, if it was explicit it would be a white.

not an issue

Instead of "0" as the first entry I just put "Sun" as the first entry.

Putting "Hello Ikarus" for the first entry would be entertaining... but both too direct and too indirect.