Retry conntrack, after a short delay, in a loop.

test/exec/exec.go

@@ -4,31 +4,39 @@ import (
 	"bytes"
 	"io"
 	"io/ioutil"
-	"os"
 
 	"github.com/weaveworks/scope/common/exec"
 )
 
 type mockCmd struct {
 	io.ReadCloser
+	quit chan struct{}
+}
+
+type blockingReader struct {
+	quit chan struct{}
 }
 
 // NewMockCmdString creates a new mock Cmd which has s on its stdout pipe
 func NewMockCmdString(s string) exec.Cmd {
 	return &mockCmd{
-		struct {
+		ReadCloser: struct {
 			io.Reader
 			io.Closer
 		}{
 			bytes.NewBufferString(s),
 			ioutil.NopCloser(nil),
 		},
+		quit: make(chan struct{}),
 	}
 }
 
 // NewMockCmd creates a new mock Cmd with rc as its stdout pipe
 func NewMockCmd(rc io.ReadCloser) exec.Cmd {
-	return &mockCmd{rc}
+	return &mockCmd{
+		ReadCloser: rc,
+		quit:       make(chan struct{}),
+	}
 }
 
 func (c *mockCmd) Start() error {
@@ -43,6 +51,21 @@ func (c *mockCmd) StdoutPipe() (io.ReadCloser, error) {
 	return c.ReadCloser, nil
 }
 
-func (c *mockCmd) Process() *os.Process {
+func (c *mockCmd) StderrPipe() (io.ReadCloser, error) {
+	return &blockingReader{c.quit}, nil
+}
+
+func (c *mockCmd) Kill() error {
+	close(c.quit)
+	return nil
+}
+
+func (b *blockingReader) Read(p []byte) (n int, err error) {
+	<-b.quit
+	return 0, nil
+}
+
+func (b *blockingReader) Close() error {
+	<-b.quit
 	return nil
 }