s3: add s3 copy

fix https://github.com/chrislusf/seaweedfs/issues/1190

weed/s3api/s3api_test.go

@@ -0,0 +1,32 @@
+package s3api
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCopyObjectResponse(t *testing.T) {
+
+	// https://docs.aws.amazon.com/AmazonS3/latest/API/API_CopyObject.html
+
+	response := CopyObjectResult{
+		ETag:         "12345678",
+		LastModified: time.Now(),
+	}
+
+	println(string(encodeResponse(response)))
+
+}
+
+func TestCopyPartResponse(t *testing.T) {
+
+	// https://docs.aws.amazon.com/AmazonS3/latest/API/API_UploadPartCopy.html
+
+	response := CopyPartResult{
+		ETag:         "12345678",
+		LastModified: time.Now(),
+	}
+
+	println(string(encodeResponse(response)))
+
+}