add coverage

Signed-off-by: Won Jun Jang <wjang@uber.com>

Author: black-adder

plugin/storage/cassandra/spanstore/writer_options_test.go

@@ -0,0 +1,28 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package spanstore
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/uber/jaeger/plugin/storage/cassandra/spanstore/dbmodel"
+)
+
+func TestWriterOpetions(t *testing.T) {
+	opts := applyOptions(TagFilter(dbmodel.DefaultTagFilter))
+	assert.Equal(t, dbmodel.DefaultTagFilter, opts.tagFilter)
+}