Added missing test case for migrations when using sql structure
use name specified by 'as' for automatic inverse association to avoid reflecting on wrong association
Remove unused require

We're not longer using `ipaddr` in schema dumper
remove unnused method from test
fix bug in email with name example code

The display name in the email "to" field needs to be quoted otherwise
your email-sending service will fail when trying to deliver mail to
user's with commas in their name (i.e. John Smith, M.D.).
Merge pull request #15655 from fabianrbz/remove-unused-method-in-test

remove unnused method from test
Merge pull request #15647 from sgrif/sg-unused-require

Remove unused require
Removed warning actionpack url.rb

Before:

/Users/Juan/dev/rails/actionpack/lib/action_dispatch/http/url.rb:95: warning: shadowing outer local variable - port

After:

No warning
Merge pull request #15662 from JuanitoFatas/patch/remove-warning

Removed variable shawdowing warning in actionpack url.rb
Add unregister_template_handler to prevent leaks.
Fixed automatic maintaining test schema to properly handle sql structure schema format.

Additionally:
* It changes `purge` task on `sqlite3` adapter to recreate database file, to
be consistent with other adapters.
* Adds `purge` step when loading from `schema.rb`
Merge pull request #15590 from zuhao/refactor_actionview_register_template_handler

Add unregister_template_handler to prevent leaks.

Conflicts:
	actionview/CHANGELOG.md
Merge pull request #15394 from morgoth/fix-automatic-maintaining-test-schema-for-sql-format

ActiveRecord::Migration.maintain_test_schema! doesn't work with structure.sql

Conflicts:
	activerecord/CHANGELOG.md
use Ruby for mocking
reduce calls to `named_host?`

`normalize_host` already calls `named_host?`, so there is no reason to
test `named_host?` again in the `extract_domain` method.
only extract domain from the options hash once
lookup subdomain from the options hash once, defaulting to true

if the subdomain wasn't specified, it's the same as if specifying
:subdomain as `true`, so we can default the value to `true` safely.
[ci skip] Correct output of #assert_not
only check named_host? once in normalize_host
Update test data which doesn't reflect expected usage

Topics call `serialize :content`, which means that the values in the
database should be YAML encoded, and we would only expect to receive
YAML strings to `update_column` and `update_columns`.