PHPUnit with SQlite database throws 'too many connections' error.

I am using SQlite database for testing my backend with my Laravel APP. The problem I get is that when I am running a test (I have approximately 800 tests), they just hang at test around 120-130 with an error:

'Too many connections'

Whats odd is that they run without any problem on the server. Also I have another machine which has Linux as well as server - and tests also stop there. And my colleague also has troubles when running tests, though he gets an error earlier in another file.

If I run all tests manually one by one - they pass without any problem.