Make a pass on unit and integration tests.

The idea is to complete the tests. IMPORTANT: we do not replace the existing ones. For each existing test files, we create a new file with _bis suffix and inside we add the new tests avoiding duplication.

We need unit and integration tests with a clear separation in the files. Please comment. For the tests for the logic, when fake structs need to be created, they must be at top level, so please write it inside the test files, at the top of the files, before the test function. To avoid any ambiguity, give unique names for the structs, regarding of the files.