test: separate detection of overlay support from every stacker run.

In unpriv test mode, we were running 'stacker testsuite-check-overlay'
every time we ran stacker.

That was causing me confusion and also is just wasteful, as the ability
to use overlay does not change within the course of a test run.

This introduces 'suite_setup' which ideally would be used by the bats
'suite_setup' functionality.  However, the Ubuntu 22.04 verison of bats
does not *have* that functionalty.

When run with '-j', this code will run more than once, but will worst
case only run once per test, rather than once per invocation of
'stacker' (some tests invoke stacker many times).

Also, adjust output of run_stacker function to be more useful
than just "Debug mode: "

Signed-off-by: Scott Moser <smoser@brickies.net>
Signed-off-by: Serge E. Hallyn <serge@hallyn.com>

test/helpers.bash

@@ -9,28 +9,29 @@ if [ "$(id -u)" != "0" ]; then
 fi
 
 function skip_if_no_unpriv_overlay {
-    run sudo -u $SUDO_USER "${ROOT_DIR}/stacker" --debug internal-go testsuite-check-overlay
-    echo $output
-    [ "$status" -eq 50 ] && skip "need newer kernel for unpriv overlay"
-    [ "$status" -eq 0 ]
+    case "$UNPRIV_OVERLAY_SUPPORT" in
+        true) return 0;;
+        false) skip "need newer kernel for unpriv overlay";;
+        "") echo "UNPRIV_OVERLAY_SUPPORT was not set; stacker_setup must be called";;
+        *) echo "UNPRIV_OVERLAY_SUPPORT set to unexpected value '$UNPRIV_OVERLAY_SUPPORT'";;
+    esac
+    exit 1
 }
 
 function run_stacker {
-    echo "Debug mode: $NO_DEBUG"
+    # add --debug unless NO_DEBUG=1
+    if [ "$NO_DEBUG" != "1" ]; then
+        set -- --debug "$@"
+    fi
+
     if [ "$PRIVILEGE_LEVEL" = "priv" ]; then
-        if [[ -n "$NO_DEBUG" && "$NO_DEBUG" = 1 ]]; then
-            run "${ROOT_DIR}/stacker" "$@"
-        else
-            run "${ROOT_DIR}/stacker" --debug "$@"
-        fi
+        set -- run "${ROOT_DIR}/stacker" "$@"
     else
         skip_if_no_unpriv_overlay
-        if [[ -n "$NO_DEBUG" && "$NO_DEBUG" = 1 ]]; then
-            run sudo -u $SUDO_USER "${ROOT_DIR}/stacker" "$@"
-        else
-            run sudo -u $SUDO_USER "${ROOT_DIR}/stacker" --debug "$@"
-        fi
+        set -- run sudo -u "$SUDO_USER" "${ROOT_DIR}/stacker" "$@"
     fi
+    echo "execute stacker as uid=$(id -u):" "$@"
+    "$@"
 }
 
 function image_copy {
@@ -61,16 +62,87 @@ function sha() {
     echo $(sha256sum $1 | cut -f1 -d" ")
 }
 
-function stacker_setup() {
-    export TEST_TMPDIR=$(tmpd $BATS_TEST_NAME)
-    cd $TEST_TMPDIR
+# with a newer bats version, this would be the suite_setup function.
+# with Ubuntu 22.04 version (1.21) we have to abuse BATS_RUN_TMPDIR
+# and an atomically written state file.  The setup could be run more
+# than once due to TOCTOU race but the result should be the same each
+# time and if the file is sourced it should be consistent.
+function suite_setup() {
+    local statef="${BATS_RUN_TMPDIR}/stacker_suite_setup.state"
 
-    if [ "$PRIVILEGE_LEVEL" = "priv" ]; then
+    if source "$statef" >/dev/null 2>&1; then
+        echo "[$$/${BATS_TEST_NAME}] used existing $statef"
         return
     fi
 
-    "${ROOT_DIR}/stacker" unpriv-setup
-    chown -R $SUDO_USER:$SUDO_USER .
+    echo "[$$/${BATS_TEST_NAME}] doing suite_setup"
+    local startd="$PWD" workd="" setupd=""
+    workd=$(tmpd suite-setup)
+    cd "$workd"
+    give_user_ownership "$workd"
+
+    if [ "$PRIVILEGE_LEVEL" = "unpriv" ]; then
+        if [ -z "$UNPRIV_SETUP" ]; then
+            setupd="$workd/unprivsetup-d"
+            mkdir "$setupd"
+            give_user_ownership "$setupd"
+            cd "$setupd"
+            run "${ROOT_DIR}/stacker" unpriv-setup
+            if [ $status -ne 0 ]; then
+                echo "$output"
+                echo "Failed unpriv-setup"
+                exit 1
+            fi
+            UNPRIV_SETUP="done"
+            cd "$workd"
+            rm -Rf "$setupd"
+        fi
+
+        if [ -z "$UNPRIV_OVERLAY_SUPPORT" ]; then
+            setupd="$workd/unpriv-check-overlay-d"
+            mkdir "$setupd"
+            give_user_ownership "$setupd"
+            cd "$setupd"
+            run sudo -u "$SUDO_USER" "${ROOT_DIR}/stacker" \
+                --debug internal-go testsuite-check-overlay
+            case "$status" in
+                50) UNPRIV_OVERLAY_SUPPORT=false;;
+                0)  UNPRIV_OVERLAY_SUPPORT=true;;
+                *)  echo "testsuite-check-overlay exited with unexpected value $status"
+                    echo "$output"
+                    exit 1;;
+            esac
+            cd "$workd"
+            rm -Rf "$setupd"
+        fi
+    fi
+
+    printf "%s\n%s\n" \
+        "UNPRIV_OVERLAY_SUPPORT=${UNPRIV_OVERLAY_SUPPORT}" \
+        "UNPRIV_SETUP=${UNPRIV_SETUP}" \
+        > "$statef.$$"
+
+    mv "$statef.$$" "$statef"
+    cd "$startd"
+}
+
+function stacker_setup() {
+    suite_setup
+
+    export TEST_TMPDIR=$(tmpd $BATS_TEST_NAME)
+    cd "$TEST_TMPDIR"
+    give_user_ownership .
+}
+
+function give_user_ownership() {
+   if [ "$PRIVILEGE_LEVEL" = "priv" ]; then
+      return
+   fi
+   if [ -z "$SUDO_UID" ]; then
+      echo "PRIVILEGE_LEVEL=$PRIVILEGE_LEVEL but empty SUDO_USER"
+      exit 1
+   fi
+   chown -R "$SUDO_USER:$SUDO_USER" "$@"
 }
 
 function cleanup() {