testutils: add e2e testing helper code

testutils/cmd.go

@@ -0,0 +1,77 @@
+// Copyright 2016 CNI authors
+//
+// 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 testutils
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+
+	"github.com/containernetworking/cni/pkg/types"
+)
+
+func envCleanup() {
+	os.Unsetenv("CNI_COMMAND")
+	os.Unsetenv("CNI_PATH")
+	os.Unsetenv("CNI_NETNS")
+	os.Unsetenv("CNI_IFNAME")
+}
+
+func CmdAddWithResult(cniNetns, cniIfname string, f func() error) (*types.Result, error) {
+	os.Setenv("CNI_COMMAND", "ADD")
+	os.Setenv("CNI_PATH", os.Getenv("PATH"))
+	os.Setenv("CNI_NETNS", cniNetns)
+	os.Setenv("CNI_IFNAME", cniIfname)
+	defer envCleanup()
+
+	// Redirect stdout to capture plugin result
+	oldStdout := os.Stdout
+	r, w, err := os.Pipe()
+	if err != nil {
+		return nil, err
+	}
+
+	os.Stdout = w
+	err = f()
+	w.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	// parse the result
+	out, err := ioutil.ReadAll(r)
+	os.Stdout = oldStdout
+	if err != nil {
+		return nil, err
+	}
+
+	result := types.Result{}
+	err = json.Unmarshal(out, &result)
+	if err != nil {
+		return nil, err
+	}
+
+	return &result, nil
+}
+
+func CmdDelWithResult(cniNetns, cniIfname string, f func() error) error {
+	os.Setenv("CNI_COMMAND", "DEL")
+	os.Setenv("CNI_PATH", os.Getenv("PATH"))
+	os.Setenv("CNI_NETNS", cniNetns)
+	os.Setenv("CNI_IFNAME", cniIfname)
+	defer envCleanup()
+
+	return f()
+}