array: add a test for even num of elements

And drop duplicating code from _pkg.dev.

_pkg.dev/wire/util/slice/slice.go

@@ -1,15 +0,0 @@
-package slice
-
-// Reverse return a reversed version of the given byte slice.
-func Reverse(b []byte) []byte {
-	// Protect from big.Ints that have 1 len bytes.
-	if len(b) < 2 {
-		return b
-	}
-
-	dest := make([]byte, len(b))
-	for i, j := 0, len(b)-1; i < j+1; i, j = i+1, j-1 {
-		dest[i], dest[j] = b[j], b[i]
-	}
-	return dest
-}

_pkg.dev/wire/util/slice/slice_test.go

@@ -1,33 +0,0 @@
-package slice
-
-import (
-	"bytes"
-	"testing"
-)
-
-func TestSliceReverse(t *testing.T) {
-	arr := []byte{0x01, 0x02, 0x03, 0x04}
-	have := Reverse(arr)
-	want := []byte{0x04, 0x03, 0x02, 0x01}
-	if bytes.Compare(have, want) != 0 {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-func TestSliceReverseOddNumberOfElements(t *testing.T) {
-	arr := []byte{0x01, 0x02, 0x03, 0x04, 0x05}
-	have := Reverse(arr)
-	want := []byte{0x05, 0x04, 0x03, 0x02, 0x01}
-	if bytes.Compare(have, want) != 0 {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}
-
-// This tests a bug that occured with arrays of size 1
-func TestSliceReverseLen2(t *testing.T) {
-	arr := []byte{0x01}
-	have := Reverse(arr)
-	want := []byte{0x01}
-	if bytes.Compare(have, want) != 0 {
-		t.Fatalf("expected %v got %v", want, have)
-	}
-}

pkg/util/array_test.go

@@ -5,7 +5,16 @@ import (
 	"testing"
 )
 
-func TestArrayReverse(t *testing.T) {
+func TestArrayEvenReverse(t *testing.T) {
+	arr := []byte{0x01, 0x02, 0x03, 0x04}
+	have := ArrayReverse(arr)
+	want := []byte{0x04, 0x03, 0x02, 0x01}
+	if !bytes.Equal(have, want) {
+		t.Fatalf("expected %v got %v", want, have)
+	}
+}
+
+func TestArrayOddReverse(t *testing.T) {
 	arr := []byte{0x01, 0x02, 0x03, 0x04, 0x05}
 	have := ArrayReverse(arr)
 	want := []byte{0x05, 0x04, 0x03, 0x02, 0x01}