test/system: Don't use XDG_CACHE_HOME or HOME for temporary files

The XDG_CACHE_HOME environment variable is supposed to default to
$HOME/.cache [1], just as it did in the test suite, and this location is
meant to be used as a cache for 'normal' use by the user.  Test suites
generally don't qualify as 'normal' use.

One expects that deleting the cache shouldn't affect 'normal' use other
than degrading performance.  However, deleting these temporary files
used by the test suite will cause actual breakage.  Even if the user
doesn't manually delete the cache, two concurrent invocations of the
test suite can do so or lead to other unexpected collisions, because the
paths are constant across multiple invocations.

Therefore, it's better to limit the scope of the test suite's temporary
files within the sandbox offered by Bats [2].  The sandbox is clearly
labelled as being used by Bats, is unique for each invocation, and Bats
takes care of cleaning everything up once it has finished running.

Note that there's no need for the system-test-storage sub-directory
under BATS_SUITE_TMPDIR.  So it was left out.

[1] https://specifications.freedesktop.org/basedir-spec/latest/

[2] https://bats-core.readthedocs.io/en/stable/writing-tests.html

https://github.com/containers/toolbox/pull/1645

test/system/libs/helpers.bash

@@ -4,14 +4,11 @@ load 'libs/bats-support/load'
 load 'libs/bats-assert/load'
 
 # Helpful globals
-readonly TEMP_BASE_DIR="${XDG_CACHE_HOME:-$HOME/.cache}/toolbx"
-readonly TEMP_STORAGE_DIR="${TEMP_BASE_DIR}/system-test-storage"
-
 readonly IMAGE_CACHE_DIR="${BATS_SUITE_TMPDIR}/image-cache"
-readonly ROOTLESS_PODMAN_STORE_DIR="${TEMP_STORAGE_DIR}/storage"
-readonly ROOTLESS_PODMAN_RUNROOT_DIR="${TEMP_STORAGE_DIR}/runroot"
-readonly PODMAN_STORE_CONFIG_FILE="${TEMP_STORAGE_DIR}/storage.conf"
-readonly DOCKER_REG_ROOT="${TEMP_STORAGE_DIR}/docker-registry-root"
+readonly ROOTLESS_PODMAN_STORE_DIR="${BATS_SUITE_TMPDIR}/storage"
+readonly ROOTLESS_PODMAN_RUNROOT_DIR="${BATS_SUITE_TMPDIR}/runroot"
+readonly PODMAN_STORE_CONFIG_FILE="${BATS_SUITE_TMPDIR}/storage.conf"
+readonly DOCKER_REG_ROOT="${BATS_SUITE_TMPDIR}/docker-registry-root"
 readonly DOCKER_REG_CERTS_DIR="${BATS_SUITE_TMPDIR}/certs"
 readonly DOCKER_REG_AUTH_DIR="${BATS_SUITE_TMPDIR}/auth"
 readonly DOCKER_REG_URI="localhost:50000"
@@ -43,23 +40,12 @@ function _setup_environment() {
 }
 
 function _setup_containers_storage() {
-  mkdir -p "${TEMP_STORAGE_DIR}"
   # Set up a storage config file for PODMAN
   echo -e "[storage]\n  driver = \"overlay\"\n  rootless_storage_path = \"${ROOTLESS_PODMAN_STORE_DIR}\"\n  runroot = \"${ROOTLESS_PODMAN_RUNROOT_DIR}\"\n" > "${PODMAN_STORE_CONFIG_FILE}"
   export CONTAINERS_STORAGE_CONF="${PODMAN_STORE_CONFIG_FILE}"
 }
 
 
-function _clean_temporary_storage() {
-  podman system reset --force >/dev/null
-
-  rm --force --recursive "${ROOTLESS_PODMAN_STORE_DIR}"
-  rm --force --recursive "${ROOTLESS_PODMAN_RUNROOT_DIR}"
-  rm --force --recursive "${PODMAN_STORE_CONFIG_FILE}"
-  rm --force --recursive "${TEMP_STORAGE_DIR}"
-}
-
-
 # Pulls an image using Podman and saves it to a image dir using Skopeo
 #
 # Parameters
@@ -202,19 +188,19 @@ function _setup_docker_registry() {
   assert_success
 
   run podman login \
-    --authfile "${TEMP_BASE_DIR}/authfile.json" \
+    --authfile "${BATS_SUITE_TMPDIR}/authfile.json" \
     --username user \
     --password user \
     "${DOCKER_REG_URI}"
   assert_success
 
   # Add fedora-toolbox:34 image to the registry
-  run skopeo copy --dest-authfile "${TEMP_BASE_DIR}/authfile.json" \
+  run skopeo copy --dest-authfile "${BATS_SUITE_TMPDIR}/authfile.json" \
     dir:"${IMAGE_CACHE_DIR}"/fedora-toolbox-34 \
     docker://"${DOCKER_REG_URI}"/fedora-toolbox:34
   assert_success
 
-  run rm "${TEMP_BASE_DIR}/authfile.json"
+  run rm "${BATS_SUITE_TMPDIR}/authfile.json"
   assert_success
 }
 

test/system/setup_suite.bash

@@ -86,5 +86,5 @@ teardown_suite() {
   fi
 
   _clean_cached_images
-  _clean_temporary_storage
+  podman system reset --force >/dev/null
 }