I've come across a potential issue when writing an integration test for one of our plugins using the ElasticsearchIntegrationTest class. This is in version 1.7.3.
When a plugin tries to make a request to Elasticsearch, it will receive an error due to the assert in org.elasticsearch.transport.Transports which is checking if the current thread is a transport thread.
I have created a github repo which demonstrates the issue: https://github.com/jaranflaath/es-plugin-integrationtest
Running the PluginTest will reproduce the situation.
I am not certain if this is an issue in Elasticsearch, or an issue with the way we try to test our plugin, so any input is welcome.