Rails 5 fix NoMethodError: undefined method 'message' for nil:NilClass in host_spec.rb

ee/changelogs/unreleased/rails5-fix-loadbalancing-host-spec.yml

+---
+title: 'Rails 5 fix NoMethodError: undefined method ''message'' for nil:NilClass in
+  host_spec.rb'
+merge_request: 6589
+author: Jasper Maes
+type: fixed

ee/spec/lib/gitlab/database/load_balancing/host_spec.rb

@@ -12,6 +12,24 @@ describe Gitlab::Database::LoadBalancing::Host, :postgresql do
       .and_return(ActiveRecord::Base.connection_pool)
   end
 
+  def raise_and_wrap(wrapper, original)
+    raise original
+  rescue original.class
+    raise wrapper.new('boom')
+  end
+
+  def wrapped_exception(wrapper, original)
+    if Gitlab.rails5?
+      begin
+        raise_and_wrap(wrapper, original.new)
+      rescue wrapper => error
+        error
+      end
+    else
+      wrapper.new('boom', original.new)
+    end
+  end
+
   describe '#connection' do
     it 'returns a connection from the pool' do
       expect(host.pool).to receive(:connection)
@@ -95,11 +113,11 @@ describe Gitlab::Database::LoadBalancing::Host, :postgresql do
 
     context 'when the replica is not online' do
       it 'returns false when ActionView::Template::Error is raised' do
-        error = StandardError.new
+        wrapped_error = wrapped_exception(ActionView::Template::Error, StandardError)
 
         allow(host)
           .to receive(:check_replica_status?)
-          .and_raise(ActionView::Template::Error.new('boom', error))
+          .and_raise(wrapped_error)
 
         expect(host).not_to be_online
       end
@@ -274,9 +292,11 @@ describe Gitlab::Database::LoadBalancing::Host, :postgresql do
     end
 
     it 'returns nil when the database connection fails' do
+      wrapped_error = wrapped_exception(ActionView::Template::Error, StandardError)
+
       allow(host)
         .to receive(:connection)
-        .and_raise(ActionView::Template::Error.new('boom', StandardError.new))
+        .and_raise(wrapped_error)
 
       expect(host.replication_lag_size).to be_nil
     end
@@ -311,9 +331,11 @@ describe Gitlab::Database::LoadBalancing::Host, :postgresql do
     end
 
     it 'returns false when the connection fails' do
+      wrapped_error = wrapped_exception(ActionView::Template::Error, StandardError)
+
       allow(host)
         .to receive(:connection)
-        .and_raise(ActionView::Template::Error.new('boom', StandardError.new))
+        .and_raise(wrapped_error)
 
       expect(host.caught_up?('foo')).to eq(false)
     end