W, [2020-08-03T13:29:43.057611 #15929]  WARN -- ddtrace: [ddtrace] Failed to collect environment information: undefined method `url' for #<Datadog::Transport::HTTP::Adapters::Test:0x00007fde4b256bc0> location: /Users/cyril/.rbenv/versions/2.7.1/lib/ruby/gems/2.7.0/gems/ddtrace-0.38.0/lib/ddtrace/diagnostics/environment_logger.rb:111:in `agent_url'

Datadog.configure do |c|
  c.use(:rails)

  c.tracer.enabled = true

  # Set transport to no-op mode. Enable tracer so that the stack is the same on every env (test, staging, etc.),
  # but only send the event to datadog agent in production.
  # The datadog agent will only accept apm http calls in production anyway.
  c.tracer.transport_options = proc { |t| t.adapter(:test) } unless Rails.env.production?
end

module TestAdapterUrlMethod
  def url
    ''
  end
end
Datadog::Transport::HTTP::Adapters::Test.prepend(TestAdapterUrlMethod)