Suppress Ruby warnings when running specs - ruby-on-rails

Question

I'm looking for a way to suppress Ruby warnings when I run my specs.
spec spec/models/account_spec.rb
I receive warnings such as:
DEPRECATION WARNING: ActiveSupport::Dependencies.load_paths is deprecated, ...
warning: already initialized constant SOME_CONSTANT_NAME
Removing the ActiveSupport warning is quite easy with ActiveSupport::Deprecation.silenced = true.
How do I prevent the already initialized constant warnings as part of my spec command? Or through creating another spec file that can suppress such warnings. Keep in mind that these warnings are from gem files, therefore I cannot go into those files and surround them with Kernel.silence_warnings.
Note:
I understand that suppressing warnings are bad. However, when I run a single spec from within vim it would be nice if the warnings didn't clutter my screen.

Answer 1

The syntax for RUBYOPT is
RUBYOPT="-W0" rspec
Tested in ruby 2.1.x and 2.14.x

Answer 2

If you run your specs directly with the ruby command instead of the spec wrapper, you can use the -W command line option to silence warnings:
$ ruby --help
[...]
-W[level] set warning level; 0=silence, 1=medium, 2=verbose (default)
So in your case:
$ ruby -W0 -Ispec spec/models/event_spec.rb
should not show you any warnings.
Alternatively, you could set $VERBOSE=nil before your gems are loaded, ie at the top of your environment.rb (or application.rb if you're on Rails 3). Note that this disables all warnings all the time.
Or, since you are using Rails, you should be able to use Kernel.silence_warnings around the Bundler.require block if you're using Bundler:
Kernel.silence_warnings do
Bundler.require(:default, Rails.env) if defined?(Bundler)
end
More selectively, set $VERBOSE only for loading specific gems:
config.gem 'wellbehaving_gem'
original_verbosity = $VERBOSE
$VERBOSE = nil
config.gem 'noisy_gem_a'
$VERBOSE = original_verbosity

Answer 3

Related with this post, you can manage deprecation warnings according to th environment in which you are working, as said in rails guides:
active_support.deprecation_behavior Sets up deprecation reporting for
environments, defaulting to :log for development, :notify for
production and :stderr for test. If a value isn't set for
config.active_support.deprecation then this initializer will prompt
the user to configure this line in the current environment's
config/environments file. Can be set to an array of values.
So just change in config/environments/test.rb the value :stderr for :log
Rails.application.configure do
...
# Print deprecation notices to the log file instead of console.
config.active_support.deprecation = :log
...
end
And with this change, the deprecation warnings will now be printed to the log/test.log instead of the console output.

Answer 4

You can also use the "RUBYOPT" environment variable to pass -W0 to rspec:
RUBYOPT=W0 rspec spec/models/event_spec.rb
This allows you to run multiple specs by passing in a directory
RUBYOPT=W0 rspec spec/models

Answer 5

The only solution that worked for me is to add $VERBOSE = nil on top of my config/environments/test.rb file
Rails.application.configure do
$VERBOSE = nil
I'm with faker warning problems faker-1.9.6/lib/faker/default/number.rb:34.
Use it local because it hides all other warnings.

Answer 6

Putting Warning[:deprecated] = false after require "rails/all" in config/application.rb works very well to suppress those warnings everywhere. You can do
Warning[:deprecated] = false if Rails.env.test?
for your particular case, or better yet - put it in config/environments/test.rb, but I'm not sure how well it is going to work since I belive some stuff is loaded before that.

Answer 7

If you have this in your .rspec file, remove
--warnings
from your .rspec file in your project root.

Answer 8

rspec has a tag option you can use -- I simply used /dev/null.
rspec spec --deprecation-out /dev/null

Answer 9

Actually, perhaps you shouldn't ignore your warnings, but test them, to make sure they are fired where they're supposed to be.
It's not the easiest to use, but it looks like this:
obj.should_receive(:warn).with("Some Message")
I found it here, and tested it for my use case, and it works (and the warnings disappear from the console, of course)

Answer 10

If you're using guard for tests and Rails 6 and you get warnings such as:
- "warning: FILE in eval may not return location in binding"
- "warning: Capturing the given block using Proc.new is deprecated; use &block instead"
- "warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call"
Then the only way so remove them all is to:
Add $VERBOSE = nil to config/environments/test.rb
Run guard with: RUBYOPT='-W0' bundle exec guard
I guess this is not good advice to remove all those warnings so later on, after a few gem updates, we should remove those lines again so that we get the right warnings on your own code usage for example.