You are talking about Belarus, and looking at
https://www.worldometers.info/coronavirus/ (assuming that the statistics is accurate) the following large developed countries have done less tests per capita than Belarus: Japan, Greece, S. Korea, Sweden, France, Hong Kong, Finland, Czechia, Canada, US, Norway, Switzerland.
Whereas UK, Australia, Germany, and Russia have tested more per capita.
There is no obvious pattern in that, meaning that tests per capita is
in itself not a meaningful measure - if you can contact trace and contain the early cases, you avoid it spreading through the entire country and then you don't need massive testing.