Fix the unit test cases caused by #191

spec/filters/elasticsearch_spec.rb

@@ -60,9 +60,18 @@
         allow(plugin).to receive(:get_client).and_return(filter_client)
         allow(filter_client).to receive(:serverless?).and_return(true)
         allow(filter_client).to receive(:client).and_return(es_client)
-        allow(es_client).to receive(:info).with(a_hash_including(:headers => LogStash::Filters::ElasticsearchClient::DEFAULT_EAV_HEADER)).and_raise(
-          Elasticsearch::Transport::Transport::Errors::BadRequest.new
-        )
+
+        if elastic_ruby_v8_client_available?
+          allow(es_client).to receive(:info)
+                                .with(a_hash_including(
+                                        :headers => LogStash::Filters::ElasticsearchClient::DEFAULT_EAV_HEADER))
+                                .and_raise(Elastic::Transport::Transport::Errors::BadRequest.new)
+        else
+          allow(es_client).to receive(:info)
+                                .with(a_hash_including(
+                                        :headers => LogStash::Filters::ElasticsearchClient::DEFAULT_EAV_HEADER))
+                                .and_raise(Elasticsearch::Transport::Transport::Errors::BadRequest.new)
+        end
       end
 
       it "raises an exception when Elastic Api Version is not supported" do
@@ -103,7 +112,11 @@
 
     before(:each) do
       allow(LogStash::Filters::ElasticsearchClient).to receive(:new).and_return(client)
-      allow(client).to receive(:es_transport_client_type).and_return('elasticsearch_transport')
+      if elastic_ruby_v8_client_available?
+        allow(client).to receive(:es_transport_client_type).and_return('elastic_transport')
+      else
+        allow(client).to receive(:es_transport_client_type).and_return('elasticsearch_transport')
+      end
       allow(client).to receive(:search).and_return(response)
       allow(plugin).to receive(:test_connection!)
       allow(plugin).to receive(:setup_serverless)
@@ -348,7 +361,11 @@
 
       before do
         allow(plugin).to receive(:get_client).and_return(client_double)
-        allow(client_double).to receive(:es_transport_client_type).and_return('elasticsearch_transport')
+        if elastic_ruby_v8_client_available?
+          allow(client_double).to receive(:es_transport_client_type).and_return('elastic_transport')
+        else
+          allow(client_double).to receive(:es_transport_client_type).and_return('elasticsearch_transport')
+        end
         allow(client_double).to receive(:client).and_return(transport_double)
       end
 
@@ -508,7 +525,12 @@ def wait_receive_request
       # this spec is a safeguard to trigger an assessment of thread-safety should
       # we choose a different transport adapter in the future.
       transport_class = extract_transport(client).options.fetch(:transport_class)
-      expect(transport_class).to equal ::Elasticsearch::Transport::Transport::HTTP::Manticore
+      if elastic_ruby_v8_client_available?
+        allow(client).to receive(:es_transport_client_type).and_return("elastic_transport")
+        expect(transport_class).to equal ::Elastic::Transport::Transport::HTTP::Manticore
+      else
+        expect(transport_class).to equal ::Elasticsearch::Transport::Transport::HTTP::Manticore
+      end
     end
 
     it 'uses a client with sufficient connection pool size' do
@@ -823,7 +845,11 @@ def wait_receive_request
 
     before(:each) do
       allow(LogStash::Filters::ElasticsearchClient).to receive(:new).and_return(client)
-      allow(client).to receive(:es_transport_client_type).and_return('elasticsearch_transport')
+      if elastic_ruby_v8_client_available?
+        allow(client).to receive(:es_transport_client_type).and_return('elastic_transport')
+      else
+        allow(client).to receive(:es_transport_client_type).and_return('elasticsearch_transport')
+      end
       allow(plugin).to receive(:test_connection!)
       allow(plugin).to receive(:setup_serverless)
       plugin.register
@@ -838,11 +864,19 @@ def wait_receive_request
     end
   end
 
-  # @note can be removed once gem depends on elasticsearch >= 6.x
-  def extract_transport(client) # on 7.x client.transport is a ES::Transport::Client
+  def extract_transport(client)
+    # on 7x: client.transport.transport
+    # on >=8.x: client.transport
     client.transport.respond_to?(:transport) ? client.transport.transport : client.transport
   end
 
+  def elastic_ruby_v8_client_available?
+    Elasticsearch::Transport
+    false
+  rescue NameError # NameError: uninitialized constant Elasticsearch::Transport if Elastic Ruby client is not available
+    true
+  end
+
   class MockResponse
     attr_reader :code, :headers