Test for Warnings Using Rspec

Test for warnings using RSpec

warn is defined in Kernel, which is included in every object. If you weren't raising the warning during initialization, you could specify a warning like this:

obj = SomeClass.new
obj.should_receive(:warn).with("Some Message")
obj.method_that_warns

Spec'ing a warning raised in the initialize method is quite more complex. If it must be done, you can swap in a fake IO object for $stderr and inspect it. Just be sure to restore it after the example

class MyClass
  def initialize
    warn "Something is wrong"
  end
end

describe MyClass do
  before do
    @orig_stderr = $stderr
    $stderr = StringIO.new
  end

  it "warns on initialization" do
    MyClass.new
    $stderr.rewind
    $stderr.string.chomp.should eq("Something is wrong")
  end

  after do
    $stderr = @orig_stderr
  end
end

How can I test in RSpec whether code I've loaded has any Ruby warnings?

I ended up initiating a new process to and evaluate the process output. In my case the issue was a redefined constant so I'm testing by loading the class twice into the new Ruby process and then using IO stream to read the output:

it 'should not redefine BUILD_FILE constant' do
    root_path = "#{File.dirname(__FILE__)}/../../../../"
    cmd = "load \"#{root_path}libraries/build_file.rb\";"
    ruby_path = 'C:/opscode/chefdk/embedded/bin/ruby.exe'

    pipe_cmd_in, pipe_cmd_out = IO.pipe
    pid = Process.spawn("#{ruby_path} -e '#{cmd} #{cmd}'", :out => pipe_cmd_out, :err => pipe_cmd_out)
    Process.wait(pid)
    pipe_cmd_out.close
    output = pipe_cmd_in.read
    puts "OUTPUT = #{output}"

    expect(output).to_not match(/previous\sdefinition\sof\sBUILD_FILE/)
end

Rspec rails printing lot of warnings

removing --warnings option from your .rspec file would do the trick

Guard with RSpec on Rails 4 giving a lot of warnings

Rspec: How to suppress warnings and notices when running tests?

Did you set: config.use_transactional_examples = true to false and see if that breaks anything?

When I run the test rspec spec In the console, I'll get a deprecation warning

Write the test in a new style:

expect(item.price).to eq 212

BTW. it seems you might doing sth quite risk/confusing. Once you assign 200 to the attribute, it will be more than confusing to see another value returned by a getter with a same name. Have you considered leaving the original method alone and defining a new one instead (like price_with_vat)?

deprecation errors when running rspec tests after updating to rails 5.0.0

The warnings were caused by the wicked_pdf gem, updating to version 1.1.0 solved the issue

How to Suppress Warnings in RSpec while running Ruby 2.7.0

These warnings/deprecations are directly from the ruby 2.7, you cannot silence them by rails or rspec configuration.

Ruby 2.7 is trying to warn you about backward incompatibilities that will arrive in ruby 3.0. See the release notes. Main source of deprecations is the Separation of positional and keyword arguments part.

Rails and other libraries and gems are not prepared for this change yet, so ruby is showing you tons of warnings.

I would wait with upgrade until gems resolve these warnings in the future, but you can also suppress these warnings according to following article https://prathamesh.tech/2019/12/26/managing-warnings-emitted-by-ruby-2-7/

RUBYOPT='-W:no-deprecated -W:no-experimental' rails c

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