Some test cases are testing only mysql adapter. We should test mysql2
adapter also.

I’m renaming all instances of `use_transcational_fixtures` to
`use_transactional_tests` and “transactional fixtures” to
“transactional tests”.

I’m deprecating `use_transactional_fixtures=`. So anyone who is
explicitly setting this will get a warning telling them to use
`use_transactional_tests=` instead.

I’m maintaining backwards compatibility—both forms will work.
`use_transactional_tests` will check to see if
`use_transactional_fixtures` is set and use that, otherwise it will use
itself. But because `use_transactional_tests` is a class attribute
(created with `class_attribute`) this requires a little bit of hoop
jumping. The writer method that `class_attribute` generates defines a
new reader method that return the value being set. Which means we can’t
set the default of `true` using `use_transactional_tests=` as was done
previously because that won’t take into account anyone using
`use_transactional_fixtures`. Instead I defined the reader method
manually and it checks `use_transactional_fixtures`. If it was set then
it should be used, otherwise it should return the default, which is
`true`. If someone uses `use_transactional_tests=` then it will
overwrite the backwards-compatible method with whatever they set.

`bound_attributes` is now used universally across the board, removing
the need for the conversion layer. These changes are mostly mechanical,
with the exception of the log subscriber. Additional, we had to
implement `hash` on the attribute objects, so they could be used as a
key for query caching.

It already treats the message

connection.

It is supposed to raise ActiveRecord::InvalidForeignKey when the
database has a fk constraint.

Follow-Up to https://github.com/rails/rails/pull/14348

Ensure that SQLCounter.clear_log is called after each test.

This is a step to prevent side effects when running tests. This will allow us to run them in random order.

This was a common pattern:
```
query = author.posts.select(:title)
connection.select_one(query)
```

However `.select` returns a ActiveRecord::AssociationRelation, which has
the bind information, so we can use that to get the right sql query.

Also fix select_rows on postgress and sqlite3 that were not using the binds

[fixes #7538]
[fixes #12017]
[related #13731]
[related #12056]

Closes #13146.

This fixes an error when using:

```
change_colum :table, :column, :bigint, array: true
```

We can conditional define the tests depending on the adapter or
connection.

Lets keep the skip for fail tests that need to be fixed.

In the end I think the pain of implementing this seamlessly was not
worth the gain provided.

The intention was that it would allow plain ruby objects that might not
live in your main application to be subclassed and have persistence
mixed in. But I've decided that the benefit of doing that is not worth
the amount of complexity that the implementation introduced.

It was a bad idea to rescue exceptions here. This can interfere with
transaction rollbacks which seems to be the cause of current CI
failure.

Instead, each adapter should implement its own DB-specific O(1)
implementation, and we fall back on the generic, slower, implementation
otherwise.

Make it the responsibility of the connection to hold onto an ARel visitor for generating SQL. This improves the code architecture generally, and solves some problems with marshalling. Adapter authors please take note: you now need to define an Adapter.visitor_for method, but it degrades gracefully with a deprecation warning for now.

On Oracle disable_referential_integrity before execution of block will disable foreign key constraints and after block will enable them but when constraints are enabled then they are validated. Therefore created record with invalid foreign key should be deleted before enabling foreign key constraints.

Refactor Active Record test connection setup. Please see the RUNNING_UNIT_TESTS file for details, but essentially you can now configure things in test/config.yml. You can also run tests directly via the command line, e.g. ruby path/to/test.rb (no rake needed, uses default db connection from test/config.yml). This will help us fix the CI by enabling us to isolate the different Rails versions to different databases.

[#4689 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Fixed adapter test cases that were failing in oracle because the asserts were looking for the presence of offset and limit which are not available in oracle. Changed the tests to check that the sql injection is not present in the output so that the tests are database adapter agnostic.

Revert "When creating database with rake, create schemas in schema_search_path if it doesn't exist."

This reverts commit 6c2a0675.

Reverting because it breaks the ability to run tests using a non-superuser.

Conflicts:

	activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
	activerecord/lib/active_record/railties/databases.rake