Add description to the test cases

Signed-off-by: Manu Gupta <manugupt1@gmail.com>

mount/mount_unix_test.go

@@ -267,10 +267,12 @@ func TestRecursiveUnmount_SubMountFailsToUnmount(t *testing.T) {
 	shadowedMounts := []string{child, grandchild}
 	for _, shadowedMount := range shadowedMounts {
 		// Unmount dir, make sure dir-other is still mounted.
-		if err := RecursiveUnmount(shadowedMount); err == nil {
-			t.Fatal("error cannot be nil")
-		} else if err != nil && !errors.Is(err, unix.ENOENT) {
-			t.Fatalf("expected error to be unix.ENOENT for shadow mount at path: %s", shadowedMount)
-		}
+		t.Run("RecursiveUnmount returns an error", func(t *testing.T) {
+			if err := RecursiveUnmount(shadowedMount); err == nil {
+				t.Fatalf("expected submount %s to return an error", shadowedMount)
+			} else if err != nil && !errors.Is(err, unix.ENOENT) {
+				t.Fatalf("expected submount(shadowed) %s to return unix.ENOENT", shadowedMount)
+			}
+		})
 	}
 }