Relocate binding body tests (#2086)

* Relocate binding body tests

Every test file should be related to a tested file.
Remove useless tests.

* Add github.com/stretchr/testify/require package

binding/msgpack_test.go

@@ -0,0 +1,32 @@
+// Copyright 2019 Gin Core Team. All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package binding
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"github.com/ugorji/go/codec"
+)
+
+func TestMsgpackBindingBindBody(t *testing.T) {
+	type teststruct struct {
+		Foo string `msgpack:"foo"`
+	}
+	var s teststruct
+	err := msgpackBinding{}.BindBody(msgpackBody(t, teststruct{"FOO"}), &s)
+	require.NoError(t, err)
+	assert.Equal(t, "FOO", s.Foo)
+}
+
+func msgpackBody(t *testing.T, obj interface{}) []byte {
+	var bs bytes.Buffer
+	h := &codec.MsgpackHandle{}
+	err := codec.NewEncoder(&bs, h).Encode(obj)
+	require.NoError(t, err)
+	return bs.Bytes()
+}