It pretty much is.
“If (a) matches (b)” is like saying “if (a) contains (b)” where (a) is the test string and (b) is the expression to be contained/matched.
If (a) is “testing” and (b) is “test”, it would be true since “ing” matches
Now this is much more useful with Regular Expressions though – let’s suppose that (a) is “ski” and (b) is [aeiou]. In regex (and thus Hopscotch), this would return true because “sk” contains a vowel (one character in the subset ). But, “sky” would return false since it does not contain a, e, i, o, or u.