Avoid downloading image if present locally

drivers/docker/docklog/docker_logger_test.go

@@ -21,20 +21,23 @@ func TestDockerLogger(t *testing.T) {
 		t.Skip("docker unavailable:", err)
 	}
 
+	if img, err := client.InspectImage("busybox:1"); err != nil || img == nil {
+		t.Log("image not found locally, downloading...")
 		err = client.PullImage(docker.PullImageOptions{
-		Repository: "alpine",
-		Tag:        "latest",
+			Repository: "busybox",
+			Tag:        "1",
 		}, docker.AuthConfiguration{})
 		if err != nil {
 			t.Fatalf("failed to pull image: %v", err)
 		}
+	}
 
 	containerConf := docker.CreateContainerOptions{
 		Config: &docker.Config{
 			Cmd: []string{
-				"/bin/ash", "-c", "touch /tmp/docklog; tail -f /tmp/docklog",
+				"/bin/sh", "-c", "touch /tmp/docklog; tail -f /tmp/docklog",
 			},
-			Image: "alpine:latest",
+			Image: "busybox:1",
 		},
 		Context: context.Background(),
 	}