This tasks implements C++ unit tests that strictly test the CE module in isolation. The statistics used in these tests will be of two kinds:

• Hand-crafted histograms 
  • with mixed types and type bracketing,
  • with bucket boundaries min/ max for the data type.

• Histograms generated from real data with known properties. Once histograms are generated from the data, the histograms are dumped so that they can be encoded directly into the unit test. The test queries are run against the real dataset, and the actual results are recorded as well. It is ensured that the histogram estimates are reasonably good wrt the actual results. Then the actual test includes: histograms, queries, and verifies that those queries produce certain (already verified) estimates.