Go Tutorial: Array example - Always passed by value

array_example.go

func TestHello(t *testing.T) {
	fmt.Println(">> Array example - Always passed by value")
	testcase1 := [1]struct {
		arg  string
		want string
	}{
		{"original arg val", "original want val"},
	}
	fmt.Println(">> testcase1.arg:", testcase1[0].arg)
	testcase2 := testcase1
	testcase1[0].arg = "changed arg val"
	fmt.Println(">> testcase2.arg:", testcase2[0].arg)
}

// Output:
>> Array example - Always passed by value
>> testcase1.arg: original arg val
>> testcase2.arg: original arg val

https://blog.golang.org/slices-intro

Observe that:

testcase1 := [...]struct {
	arg  string
	want string
}{
	{"original arg val", "original want val"},
}

is the same as:

testcase1 := [1]struct {
	arg  string
	want string
}{
	{"original arg val", "original want val"},
}