Testing is a critical step that has to be taken, but it will form only part of the whole solution.
We need to know who has and hasn't got covid within the health service, care workers, police, etc and other front line workers.
If you don't have that answer, then workers are either quaranteeing themselves for up to 14 days for no reason, or carrying on working and spreading the virus to patients, colleagues, etc.
And on a wider scale, if any member of the public thinks they have covid and are showing symptoms, it makes sense for them to get a test - where possible. It allows them to quaranteen themselves and help prevent the spread.
It isn't going to solve the problem though, we need a vaccine for that.