Question re assert_equal

rubyonrails-talk
1

In Agile Web Development with Rails, the following statement is given:

assert_equal "has already been taken", product.errors[:title].join('; ')

My question is: Why is the join(...) needed and what exactly does it do here?

If it does what I assume, join an array of strings and use "; " as the separator, then I wonder how the assert_equal statement could ever evaluate to true as the first parameter is a static string without "; "

Can you shed some light for me?

2

If there is only supposed to be one error on title (ie the errors[:title] contains a single string) then join will just return that string. Hard to say without knowing the wider context, but this seems a fairly succinct way of saying that there should only be one error for the title attribute and that it should be the one that comes from the uniqueness validation.

Fred

3

24z wrote in post #961471:

In Agile Web Development with Rails, the following statement is given:

assert_equal "has already been taken", product.errors[:title].join('; ')

My question is: Why is the join(...) needed and what exactly does it do here?

If it does what I assume, join an array of strings and use "; " as the separator, then I wonder how the assert_equal statement could ever evaluate to true as the first parameter is a static string without "; "

That seems like a strangely written assertion. Obviously, the only way it could return true is if product.errors[:title] has only one element.

Can you shed some light for me?

Best,