RUBY-2132 misc cleanup (#1944)

* report background threads not launched from examples

* reduce line length

* reformat the hash

Co-authored-by: Oleg Pudeyev <oleg@bsdpower.com>

Author: p-mongo

lib/mongo/server/monitor.rb

@@ -100,8 +100,8 @@ def heartbeat_interval
       # @deprecated
       def_delegators :server, :last_scan
 
-      # The compressor is determined during the handshake, so it must be an attribute
-      # of the connection.
+      # The compressor is determined during the handshake, so it must be an
+      # attribute of the connection.
       #
       # @deprecated
       def_delegators :connection, :compressor
@@ -126,8 +126,8 @@ def do_work
         end
       end
 
-      # Stop the background thread and wait for to terminate for a reasonable
-      # amount of time.
+      # Stop the background thread and wait for it to terminate for a
+      # reasonable amount of time.
       #
       # @return [ true | false ] Whether the thread was terminated.
       #

lib/mongo/server/monitor/connection.rb

@@ -36,7 +36,10 @@ class Connection < Server::ConnectionCommon
         # The case matters here for fail points.
         #
         # @since 2.5.0
-        ISMASTER_OP_MSG = { isMaster: 1, '$db' => Database::ADMIN }.freeze
+        ISMASTER_OP_MSG = {
+          isMaster: 1,
+          '$db' => Database::ADMIN,
+        }.freeze
 
         # The constant for the ismaster command.
         #

spec/support/background_thread_registry.rb

@@ -42,7 +42,11 @@ def verify_empty!
           if record.object.respond_to?(:options)
             msg << "\n  with options: #{record.object.options}"
           end
-          msg << "\n  in #{record.example.id} #{record.example.full_description}"
+          if record.example
+            msg << "\n  in #{record.example.id} #{record.example.full_description}"
+          else
+            msg << "\n  not in an example"
+          end
         end
         raise msg
       end