tests: Better implementation for ab30694

Don't remove the pre-existing mount-points from the blueprint b/c we
still need to assert on those.

Add `/tmp` and `/var/tmp` to exercise the case where mountpoints have
matching suffixes.

test/cases/filesystem.sh

@@ -162,6 +162,13 @@ size = "125 MiB"
 mountpoint = "/usr"
 size = 2147483648
 
+[[customizations.filesystem]]
+mountpoint = "/tmp"
+size = 131072000
+
+[[customizations.filesystem]]
+mountpoint = "/var/tmp"
+size = 131072000
 EOF
 
 build_image "$BLUEPRINT_FILE" rhel85-custom-filesystem qcow2 false
@@ -175,7 +182,7 @@ greenprint "💬 Checking mountpoints"
 INFO="$(sudo /usr/libexec/osbuild-composer-test/image-info "${IMAGE_FILENAME}")"
 FAILED_MOUNTPOINTS=()
 
-for MOUNTPOINT in '/' '/var' '/var/log' '/var/log/audit' '/usr'; do
+for MOUNTPOINT in '/' '/var' '/var/log' '/var/log/audit' '/var/tmp' '/usr' '/tmp'; do
   EXISTS=$(jq -e --arg m "$MOUNTPOINT" 'any(.fstab[] | .[] == $m; .)' <<< "${INFO}")
   if $EXISTS; then
     greenprint "INFO: mountpoint $MOUNTPOINT exists"