Added failing spec for nested rescue_from declarations

spec/grape/api/nested_rescue_from_spec.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+# see https://github.com/ruby-grape/grape/issues/1975
+
+require 'spec_helper'
+
+module NestedRescueFromSpec
+  class Alpacas < Grape::API
+    resource :alpacas do
+      rescue_from :all do
+        error_response(status: 200)
+      end
+
+      get do
+        { count_alpacas: 1 / 0 }
+      end
+    end
+  end
+
+  class Main < Grape::API
+    rescue_from ZeroDivisionError do
+      error_response(status: 500)
+    end
+
+    mount NestedRescueFromSpec::Alpacas
+  end
+end
+
+describe Grape::API do
+  subject { NestedRescueFromSpec::Main }
+
+  def app
+    subject
+  end
+
+  it 'calls the outer rescue_from :error' do
+    get '/alpacas'
+    expect(last_response.status).to eql 500
+  end
+end