Broken pytests with pytest==8.2.0

[dvmartinweigl]

Pytests are broken with version 8.2.0

postgresql_proc is delivering None for password where it used to create "".
This results in an invalid url -> d.url = f"postgresql://{d.user}:{d.password}@{d.host}:{d.port}/{d.dbname}"

• ensure all parameters for connection string are given
• add backend test for testcase with postgres connection in visyn_core