Copy files from nvidia-container-toolkit

Signed-off-by: Evan Lezar <elezar@nvidia.com>

pkg/filter/filter.go

@@ -0,0 +1,26 @@
+/*
+# Copyright (c) 2021, NVIDIA CORPORATION.  All rights reserved.
+#
+# 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 filter
+
+//go:generate moq -stub -out filter_mock.go . EnvLookup
+
+// EnvLookup defines an interface that supports the LookupEnv function for getting
+// environment variable values.
+// TODO: This belongs in a different package
+type EnvLookup interface {
+	LookupEnv(string) (string, bool)
+}