b998473673
Fixes #932 Also fixes #966 Decided not to add Summary type because it has the same functionality as Histogram but makes more calculations on client side (Clio side). See https://prometheus.io/docs/practices/histograms for detailed comparison.
Unit testing
The correctness of new implementations can be verified via running unit tests. Below are the information on how to run unit tests.
Requirements
Cassandra cluster
If you wish to test the backend component you will need to have access to a local (127.0.0.1) Cassandra cluster, opened at port 9042. Please ensure that the cluster is successfully running before running unit tests unless you filter out all Backend tests.
Running
To run the unit tests, first build Clio as normal, then execute ./clio_tests to run all unit tests.
Note: If you don't want to test the Cassandra backend code, the relevant tests can be disabled like this: ./clio_tests --gtest_filter="-BackendCassandraBaseTest*:BackendCassandraTest*:BackendCassandraFactoryTestWithDB*"
Adding Unit Tests
To add unit tests, please create a separate file for the component you are trying to cover (unless it already exists) and use any other existing unit test file as an example.