• Ruby 3.0 should be enabled

• Test.expect should be replaced

No random tests

Added various other dice to tests

The current tests aren't very informative. This would be a slight improvement:

input = ["This is an alpha line", "Beta line next!", "Another AlphA", "I have no idea", nil]
Test.assert_equals(line_types(input), [:alpha, :beta, :alpha, :unknown, :unknown])

As it stands, you only know if its pass/fail. Using the above would show you which of the elements in the returned array are wrong.

Symbols are ruby-specific, what about translating to other languages?

I think the description leads you to believe that you're looking for words (as in separated by whitespace) and not just substrings.

:alpha strings contain the word "alpha"

Good point, I've added this to the test fixture now, thank you!

Thanks for the comment-I've opted to skip that edge case altogether as this is only a 7 kyu but I'll explicitly state that this case can't happen in the description.

Thanks for the feedback, I'll state that it should be case-insensitive and add a decent test case.

Thanks for your comments, I've updated the method definition and will rule out the 'alphabeta' case in the description to avoid confusion.

Thanks, that is what I get for writing it when tired!
I've revised the description and switched it to use assert_equals, thanks for pointing that out!

This is just too good!

Sadly, that is only true until you work with someone who doesn't follow that convention.

Looks like the tests need to made a bit more stringent!