System level testing of entropy encoding

An aspect includes receiving a symbol translation table (STT) that includes input symbols and their corresponding codewords. An entropy encoding descriptor (EED) that specifies how many of the codewords have each of the different lengths is also received. Contents of one or both of the STT and the EED are modified to generate a test case and an entropy encoding test is executed. The executing includes performing a lossless data compression process based on contents of an input data string that includes one or more of the input symbols, and on contents of the STT and the EED; or performing a data expansion process based on contents of an input data string that includes one or more of the codewords, and on contents of the STT and the EED. A result of the entropy encoding test is compared to an expected result.