Move codec test helper to an internal package

codec/internal/test_helpers.go

@@ -0,0 +1,44 @@
+package internal
+
+import (
+	"encoding/gob"
+	"reflect"
+	"testing"
+
+	"github.com/asdine/storm/codec"
+)
+
+type testStruct struct {
+	Name string
+}
+
+// RoundtripTester is a test helper to test a EncodeDecoder
+func RoundtripTester(t *testing.T, c codec.EncodeDecoder, vals ...interface{}) {
+	var val, to interface{}
+	if len(vals) > 0 {
+		if len(vals) != 2 {
+			panic("Wrong number of vals, expected 2")
+		}
+		val = vals[0]
+		to = vals[1]
+	} else {
+		val = &testStruct{Name: "test"}
+		to = &testStruct{}
+	}
+
+	encoded, err := c.Encode(val)
+	if err != nil {
+		t.Fatal("Encode error:", err)
+	}
+	err = c.Decode(encoded, to)
+	if err != nil {
+		t.Fatal("Decode error:", err)
+	}
+	if !reflect.DeepEqual(val, to) {
+		t.Fatalf("Roundtrip codec mismatch, expected\n%#v\ngot\n%#v", val, to)
+	}
+}
+
+func init() {
+	gob.Register(&testStruct{})
+}