add unit test

Author: yuchen-db

internal/cortex/querier/queryrange/query_bytes_fetched_test.go

@@ -0,0 +1,20 @@
+// Copyright (c) The Cortex Authors.
+// Licensed under the Apache License 2.0.
+
+package queryrange
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestQueryBytesFetchedPrometheusResponseHeaders(t *testing.T) {
+	resp1 := PrometheusResponse{Headers: []*PrometheusResponseHeader{&PrometheusResponseHeader{Name: "M3-Fetched-Bytes-Estimate", Values: []string{"100"}}}}
+	resp2 := PrometheusResponse{Headers: []*PrometheusResponseHeader{&PrometheusResponseHeader{Name: "M3-Fetched-Bytes-Estimate", Values: []string{"1000"}}}}
+	resp3 := PrometheusResponse{}
+	hdrs := QueryBytesFetchedPrometheusResponseHeaders(&resp1, &resp2, &resp3)
+	expected := []*PrometheusResponseHeader{{Name: QueryBytesFetchedHeaderName,
+		Values: []string{"1100"}}}
+	require.Equal(t, hdrs, expected)
+}