add mock implementation of proxy query service

mock/proxy_query_service.go

@@ -0,0 +1,27 @@
+package mock
+
+import (
+	"context"
+	"io"
+
+	"github.com/influxdata/platform/query"
+)
+
+var _ query.ProxyQueryService = (*ProxyQueryService)(nil)
+
+// ProxyQueryService is a mock implementation of a query.ProxyQueryService.
+type ProxyQueryService struct {
+	QueryFn func(context.Context, io.Writer, *query.ProxyRequest) (int64, error)
+}
+
+// NewProxyQueryService returns a mock of ProxyQueryService where its methods will return zero values.
+func NewProxyQueryService() *ProxyQueryService {
+	return &ProxyQueryService{
+		QueryFn: func(context.Context, io.Writer, *query.ProxyRequest) (int64, error) { return 0, nil },
+	}
+}
+
+// Query performs the requested query and encodes the results into w.
+func (s *ProxyQueryService) Query(ctx context.Context, w io.Writer, req *query.ProxyRequest) (int64, error) {
+	return s.QueryFn(ctx, w, req)
+}