Documentation
¶
Overview ¶
Package testname hands out the unique numbers that tests use to name the databases, schemas and files they create.
It exists because time.Now().UnixNano() is not unique and the tests assumed it was. The name says nanoseconds; the clock underneath does not have to tick that fast, and on darwin/arm64 it ticks once per microsecond. Two goroutines that read it at the same moment get the same number about three times in four:
identical UnixNano in 151446/200000 parallel pairs (75.723%) smallest observed tick: 1000ns
So `fmt.Sprintf("test_evaluation_lexical_%d.db", time.Now().UnixNano())` in two parallel tests is not two databases. It is one file opened by two connection pools, and the loser reports
failed to enable foreign keys: database is locked (5) (SQLITE_BUSY)
at Open, before the test has done anything — which reads like a product fault in a store that is working perfectly.
Nano is a drop-in for the call it replaces: still an int64, still ordered, still roughly the wall clock, but never handed out twice in one process.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Nano ¶
func Nano() int64
Nano returns a number that no other caller in this process will receive.
It follows the clock when the clock is ahead and steps by one when it is not, so a sequence of calls stays ordered and stays close to the real time — which is what makes it readable in a leftover filename.
Types ¶
This section is empty.
Source Files