I'm cutting my teeth on Go and after digging into table driven tests I ran into the following problem:
I have a function that returns multiple values
// Halves an integer and and returns true if it was even or false if it was odd.
func half(n int) (int, bool) {
h := n / 2
e := n%2 == 0
return h, e
}
I know that for half(1)
the return value should be 0, false
and for half(2)
it should match 1, true
, but I can't seem to figure out how to put this on a table.
How would one go to have something that resembles the following?
var halfTests = []struct {
in int
out string
}{
{1, <0, false>},
{3, <1, true>},
}
Is there any other, more idiomatic way of doing this?
For reference, here's a test for something that resembles a FizzBuzz function, using tables:
var fizzbuzzTests = []struct {
in int
out string
}{
{1, "1"},
{3, "Fizz"},
{5, "Buzz"},
{75, "FizzBuzz"},
}
func TestFizzBuzz(t *testing.T) {
for _, tt := range fizzbuzzTests {
s := FizzBuzz(tt.in)
if s != tt.out {
t.Errorf("Fizzbuzz(%d) => %s, want %s", tt.in, s, tt.out)
}
}
}
Just add another field to your struct that holds the second return value. Example:
var halfTests = []struct {
in int
out1 int
out2 bool
}{
{1, 0, false},
{3, 1, true},
}
Your testing function would look like the following:
func TestHalf(t *testing.T) {
for _, tt := range halfTests {
s, t := half(tt.in)
if s != tt.out1 || t != tt.out2 {
t.Errorf("half(%d) => %d, %v, want %d, %v", tt.in, s, t, tt.out1, tt.out2)
}
}
}
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