Increase e2e test coverage

[kiddinn]

There are quite a few parts of the codebase that are not covered by proper unit testing, they depend too much on existing infrastructure that the tests are often mocked to the point of not being relevant enough. Therefore we need to increase the end-to-end test coverage.

This issue is supposed to track that effort. The following e2e tests need to be added:

• [ ] Increase search object tests, test query_dsl, test querying individual data sets, and other parts of the search object
• [ ] Add aggregation tests for term aggregation, manual and other parts
• [ ] Add graph tests
• [ ] Add testing the analyzers and their results
• [ ] Test stories that are automatically generated by analyzers, and test manually creating stories
• [ ] Test saved aggregations, both automatically generated by analyzers and manually created and saved.

[jaegeral]

This is kind of a broad issue, I am not sure if it would make more sense to split this issue into smaller chunks that can be taken one by one from people instead.