End to end tests

[jpkrohling]

As the complexity of the client grows, it's necessary to have end-to-end tests to make sure all the pieces are integrated correctly. @pavolloffay suggested using testcontainers with jaeger all-in-one distribution based on the following examples:

• https://github.com/opentracing-contrib/java-spring-jaeger/blob/master/opentracing-spring-jaeger-web-starter-it/src/test/java/io/opentracing/contrib/java/spring/web/jaeger/starter/it/JaegerIntegrationTest.java#L49
• https://github.com/jaegertracing/spark-dependencies/blob/master/jaeger-spark-dependencies-elasticsearch/src/test/java/io/jaegertracing/spark/dependencies/elastic/JaegerElasticsearchEnvironment.java#L63

Context: #481 (review)

[DotSpy]

@jkwatson assign me tho this one please

[andrewhsu]

looks like this one can be closed