has_and_belongs_to_many .join_table not working with symbolized table name

[allisonphillips]

I am experiencing errors when trying to add shoulda matcher specs for has_and_belongs_to_many relationships for classes that are not dependent on any gem. At first I thought I had forgotten to configure something, but then I reproduced by writing the same example for similar classes that has long been functioning in a production environment without issue. All this syntax works:

# class
has_and_belongs_to_many :association_name,
  class_name:              '::AssociationClass',
  join_table:              :join_table_name_that_definitely_exists,
  foreign_key:             foreign_key_id,
  association_foreign_key: association_foreign_key_id

# spec
it do
  should have_and_belong_to_many(:association_name)
    .class_name('::AssociationClass')
    .with_foreign_key(:foreign_key_id)
    .with_foreign_key(:association_foreign_key_id)
end

But as soon as I add .join_table(:join_table_name_that_definitely_exists) to the example block in the spec, I get the equivalent of this message:

"Expected #{described_class} to have a has_and_belongs_to_many association " \
"called #{association_name} (join table #{join_table_name} doesn't exist)"

I eventually figured out that the matcher works if you pass the join table name as a string. It appears that the matcher doesn't support table names as a symbol.

Originally posted by @allisonphillips in #625 (comment)

[mcmire]

Thanks for submitting this separately! I've got a fix for this in #1323.