Usually a test function proves only the feature described in the alarm manual. It should not be assumed to verify wastewater removal or every sensor.
What the observation means
An audible test signal and actual pump operation are different observations. Do not create a high water level to perform an improvised alarm test.
A useful next step
Use only the documented owner check and record its result accurately. If drainage is failing, stop fixture use regardless of a successful sound test. Tell the engineer which test was performed rather than claiming the whole system passed.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.