add unit tests to verify the fix

Author: azych

staging/src/k8s.io/kubelet/pkg/cri/streaming/remotecommand/httpstream_test.go

@@ -0,0 +1,65 @@
+package remotecommand
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.uber.org/goleak"
+	"k8s.io/client-go/tools/remotecommand"
+)
+
+func TestHandleResizeEvents(t *testing.T) {
+	var testTerminalSize remotecommand.TerminalSize
+	rawTerminalSize, err := json.Marshal(&testTerminalSize)
+	require.NoError(t, err)
+
+	testCases := []struct {
+		name             string
+		resizeStreamData []byte
+		cancelContext    bool
+		readFromChannel  bool
+	}{
+		{
+			name:             "data attempted to be sent on the channel; channel not read; context canceled",
+			resizeStreamData: rawTerminalSize,
+			cancelContext:    true,
+		},
+		{
+			name:             "data attempted to be sent on the channel; channel read; context not canceled",
+			resizeStreamData: rawTerminalSize,
+			readFromChannel:  true,
+		},
+		{
+			name:          "no data attempted to be sent on the channel; context canceled",
+			cancelContext: true,
+		},
+		{
+			name: "no data attempted to be sent on the channel; context not canceled",
+		},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			ctx, cancel := context.WithCancel(context.TODO())
+			connCtx := connectionContext{
+				resizeStream: io.NopCloser(bytes.NewReader(testCase.resizeStreamData)),
+				resizeChan:   make(chan remotecommand.TerminalSize),
+			}
+
+			go handleResizeEvents(ctx, connCtx.resizeStream, connCtx.resizeChan)
+			if testCase.readFromChannel {
+				gotTerminalSize := <-connCtx.resizeChan
+				require.Equal(t, gotTerminalSize, testTerminalSize)
+			}
+			if testCase.cancelContext {
+				cancel()
+			}
+
+			goleak.VerifyNone(t)
+			cancel()
+		})
+	}
+}