Integrate flink end-to-end tests with Travis

[chrisdail]

Suggestion came from slack around integrating testing of the flink connectors using the flink end-to-end tests.

From Stephan:

Or we change the build setup of the flink-connectors repository a bit:

• Travis would not call gradle directly, but instead run a test driver script
• That script would trigger initially gradle, but also run some end-to-end tests that download flink, take the compiled connector, start flink, submit a job, parse results, etc.

[fpj]

I think I know what this issue is referring to, but it is missing specifics about what these end-to-end tests are.

[EronWright]

I take the meaning to be, run gradlew test in the travis build. At the moment, travis is just building the code.

[hldnova]

I've noticed (https://travis-ci.org/pravega/flink-connectors/builds/382312652) the test was run with gradlew check, while some others don't. A little puzzled as to why.

[hldnova]

Here is what I have in mind for the end to end tests:

• build
• test
• download and compile a flink sample (at minimum exercising flink pravega writer/reader).
• download and start flink cluster
• run the flink app on the flink cluster
• some basic verification of the flink app.
• eventually extend the flink samples to cover more features (exactlyonce, streamcut, table/batch, etc.)

Functional wise, the end-to-end tests do not go much beyond the existing unit tests. The main difference is that they mimic the end user experience.

comments?

[StephanEwen]

In Flink, we have the end-to-end tests mainly to validate dependencies, classloading, config setups, multi process setups, etc. They have been useful in uncovering issues in those areas.

For a simple overview, have a look at this maven module: https://github.com/apache/flink/tree/master/flink-end-to-end-tests