Simplify the tests

Author: 0x2c7

spec/functional/topic_management_spec.rb

@@ -12,14 +12,11 @@
 
   example "deleting topics" do
     topic = generate_topic_name
-    kafka.create_topic(topic, num_partitions: 3)
 
+    kafka.create_topic(topic, num_partitions: 3)
     expect(kafka.partitions_for(topic)).to eq 3
-    kafka.delete_topic(topic)
-    kafka.instance_variable_get(:@cluster).mark_as_stale!
 
-    expect do
-      kafka.partitions_for(topic)
-    end.to raise_error(Kafka::LeaderNotAvailable)
+    kafka.delete_topic(topic)
+    expect(kafka.has_topic?(topic)).to eql(false)
   end
 end