Array and slice are pretty much equivalent. Slices require (three characters) less typing. And arrays save a couple of bytes at run-time by not allocating a slice header.
Maps, on the other hand, will execute the tests in a randomised order. In a properly written test, this should not matter. But if test results depend on the order the tests are run, you really want every run of your tests to produce the same results. Otherwise you will never know whether your tests passed because your code is correct, or because you just happened to get lucky this time with the execution order. On Monday, 23 December 2019 14:46:42 UTC, Rodolfo Carvalho wrote: > > This is a question about organizing table tests. > > I believe the most common idiom for writing table tests is to store test > cases in a slice of structs like in the example from > https://github.com/golang/go/wiki/TableDrivenTests > <https://github.com/golang/go/wiki/TableDrivenTests#example-of-a-table-driven-test> > : > > var flagtests = []struct { > in string > out string > }{ > {"%a", "[%a]"}, > // ... > {"%-1.2abc", "[%-1.2a]bc"}, > } > > I've also seen map[string]struct{...} used when one wants to give test > cases a name (described in detail in > https://dave.cheney.net/2019/05/07/prefer-table-driven-tests). > > What got me curious, however, are cases where instead of a slice literal, > the author has chosen to use an array literal. Example from the Go source > tree: > > src/net/http/cookiejar/jar_test.go:var hasDotSuffixTests = [...]struct { > src/net/http/cookiejar/jar_test.go- s, suffix string > src/net/http/cookiejar/jar_test.go-}{ > src/net/http/cookiejar/jar_test.go- {"", ""}, > src/net/http/cookiejar/jar_test.go- {"", "."}, > src/net/http/cookiejar/jar_test.go- {"", "x"}, > > > To my surprise, the array literal pattern appears more often than maps in > tests in the Go tree: > > $ git grep -F '[]struct {' -- '*_test.go' | wc -l > 742 > $ git grep -F '[...]struct {' -- '*_test.go' | wc -l > 38 > $ git grep -F 'map[string]struct {' -- '*_test.go' | wc -l > 11 > > > Why and when would one put test cases in an array literal? What is the > point? > > > Thank you and cheers, > > Rodolfo > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/11914431-bcae-4649-8fac-164c70b4c972%40googlegroups.com.
