Failing test for connection handler in Linux

[agarciamontoro]

handler_linux_test.go fails with the following error:

12:16 $ go test ./...
ok      github.com/src-d/go-mysql-server        2.559s
ok      github.com/src-d/go-mysql-server/auth   (cached)
ok      github.com/src-d/go-mysql-server/benchmark      (cached) [no tests to run]
ok      github.com/src-d/go-mysql-server/internal/regex (cached)
ok      github.com/src-d/go-mysql-server/internal/similartext   (cached)
?       github.com/src-d/go-mysql-server/internal/sockstate     [no test files]
ok      github.com/src-d/go-mysql-server/memory (cached)
time="2019-09-16T12:16:20+02:00" level=info msg="NewConnection: client 1"
--- FAIL: TestBrokenConnection (4.01s)
    require.go:172: 
                Error Trace:    handler_linux_test.go:51
                Error:          An error is expected but got nil.
                Test:           TestBrokenConnection
time="2019-09-16T12:16:24+02:00" level=info msg="NewConnection: client 1"
time="2019-09-16T12:16:24+02:00" level=info msg="NewConnection: client 1"
time="2019-09-16T12:16:24+02:00" level=info msg="NewConnection: client 2"
time="2019-09-16T12:16:24+02:00" level=info msg="kill query: pid 2"
time="2019-09-16T12:16:24+02:00" level=info msg="kill connection: id 1"
time="2019-09-16T12:16:24+02:00" level=info msg="NewConnection: client 1"
time="2019-09-16T12:16:24+02:00" level=info msg="NewConnection: client 2"
time="2019-09-16T12:16:27+02:00" level=info msg="NewConnection: client 2"
FAIL
FAIL    github.com/src-d/go-mysql-server/server 11.604s
ok      github.com/src-d/go-mysql-server/sql    (cached)
ok      github.com/src-d/go-mysql-server/sql/analyzer   (cached)
ok      github.com/src-d/go-mysql-server/sql/expression (cached)
ok      github.com/src-d/go-mysql-server/sql/expression/function        (cached)
ok      github.com/src-d/go-mysql-server/sql/expression/function/aggregation    (cached)
ok      github.com/src-d/go-mysql-server/sql/index      (cached)
ok      github.com/src-d/go-mysql-server/sql/index/pilosa       (cached)
ok      github.com/src-d/go-mysql-server/sql/parse      (cached)
ok      github.com/src-d/go-mysql-server/sql/plan       (cached)
?       github.com/src-d/go-mysql-server/test   [no test files]
FAIL

I am on current master (a478e1e), and I am running the tests from Arch Linux (kernel version 5.2.13-arch1-1-ARCH).

[juanjux]

This test is somewhat fuzzy because it depends on how quickly the OS changes into TimeWait or SockWait states. Will think of another solution.