Refactor AR's validations_test.rb

The `:context` switch feature is implemented in
ActiveRecord::Validations#valid? method, so we should rename the test
names, and execute `valid?` in the test.

Change test name in AR's validations_test.rb

This test is testing save method's code
pg guide, PostgreSQL legacy table view example. [ci skip]
ActionDispatch::Http::URL.normalize_port should not strip port for protocol relative URL.
Always use the provided port for protocol relative urls

There may be situations where you need to tunnel SSL connections over
port 80 so we shouldn't remove it if it has been explicitly provided.
Merge branch 'master' of github.com:rails/rails
adding complete message in documentation [ci skip]
Merge pull request #15058 from Gaurav2728/gaurav-doc_message

adding complete message in documentation [ci skip]
docs, make `ActionNotFound` public API. [ci skip]

This is a follow up to #15058.

This exception is regularly raised during development. This means it will enter
the user realm. We should provide an API page to show that this exception is public API.

/cc @schneems
Make TimeZone#parse behave more like Time#parse.

Namely, if the mday is omitted but any other upper components are, then instead
of supplying the mday from the current time, it defaults to 1.
Tidy up implementation of #15010
Replace :base with :in [ci skip]
Merge pull request #15059 from marcioj/patch-1

Replace :base with :in [ci skip]
Merge pull request #10662 from take/change-test-name-for-ActiveRecord--Validations#valid-

Refactor AR's validations_test.rb
Remove redundant tests method.
correcting method documentation [ci skip]
Merge pull request #15063 from cbeer/correct-attribute_present-docs

correcting method documentation [ci skip]
Update attribute_methods.rb

Improve documentation
Merge pull request #15060 from tgxworld/remove_unnecessary_tests_method

Remove redundant tests method.
Modify assert conditions not to be affected
by each database bind variable naming conventions
Merge pull request #14999 from yahonda/modify_bind_variable_name

Modify assert conditions not to be affected
by each database bind variable naming conventions

Closes #14999.