run/tests: fix flaky RunAttachTermination test

During an attached `docker run`, the CLI starts capturing signals so
that they can be forwarded to the container. The CLI stops capturing
signals after container is no longer running/it's streams are closed.

This test had two issues:
- it would close the streams early, causing the CLI to think the
  container had exited, and stop signal handling (causing the SIGINT
  to not be captured and interrupt the test instead), and
- it would send immediately on the status channel returned by WaitFunc,
  which would also signal the container has exited and caused the CLI to
  stop signal handling

This patch addresses both of these issues and makes this test less
flaky.

Signed-off-by: Laura Brehm <[email protected]>

cli/command/container/run_test.go

@@ -150,6 +150,8 @@ func TestRunAttachTermination(t *testing.T) {
 	var conn net.Conn
 	killCh := make(chan struct{})
 	attachCh := make(chan struct{})
+	startCh := make(chan struct{})
+	containerExitC := make(chan struct{})
 	fakeCLI := test.NewFakeCli(&fakeClient{
 		createContainerFunc: func(_ *container.Config, _ *container.HostConfig, _ *network.NetworkingConfig, _ *specs.Platform, _ string) (container.CreateResponse, error) {
 			return container.CreateResponse{
@@ -158,6 +160,7 @@ func TestRunAttachTermination(t *testing.T) {
 		},
 		containerKillFunc: func(ctx context.Context, containerID, signal string) error {
 			killCh <- struct{}{}
+			containerExitC <- struct{}{}
 			return nil
 		},
 		containerAttachFunc: func(ctx context.Context, containerID string, options container.AttachOptions) (types.HijackedResponse, error) {
@@ -173,11 +176,19 @@ func TestRunAttachTermination(t *testing.T) {
 			responseChan := make(chan container.WaitResponse, 1)
 			errChan := make(chan error)
 
-			responseChan <- container.WaitResponse{
-				StatusCode: 130,
-			}
+			go func() {
+				<-containerExitC
+				responseChan <- container.WaitResponse{
+					StatusCode: 130,
+				}
+			}()
 			return responseChan, errChan
 		},
+		containerStartFunc: func(containerID string, options container.StartOptions) error {
+			startCh <- struct{}{}
+			return nil
+		},
+
 		// use new (non-legacy) wait API
 		// see: 38591f20d07795aaef45d400df89ca12f29c603b
 		Version: "1.30",
@@ -201,16 +212,24 @@ func TestRunAttachTermination(t *testing.T) {
 	case <-attachCh:
 	}
 
+	// run command should attempt to start the container
+	select {
+	case <-time.After(5 * time.Second):
+		t.Fatal("containerStartCh was not called before the timeout")
+	case <-startCh:
+	}
+
 	assert.NilError(t, syscall.Kill(syscall.Getpid(), syscall.SIGINT))
-	// end stream from "container" so that we'll detach
-	conn.Close()
 
 	select {
 	case <-killCh:
 	case <-time.After(5 * time.Second):
 		t.Fatal("containerKillFunc was not called before the timeout")
 	}
 
+	// end stream from "container" so that we'll detach
+	conn.Close()
+
 	select {
 	case cmdErr := <-cmdErrC:
 		assert.Equal(t, cmdErr, cli.StatusError{