tests: get rid of yield-based tests yield-based tests (tests that are actually generating tests) are a nose feature which were also supported in pytest. However, since pytest-3.0 this type of tests is deprecated, they will be removed in pytest-4.0. The only yield tests present in the kallithea test suite are simply yielding a method that does a single assert. The benefit of having each of these asserts in a separate test is not very high. Replace the yield by a direct call to the previously-yielded method. This means the total test count reduces but the actual amount of test code is the same.