fix: Add test for rpm-ostree rebase (#161)

Adding this so that we can make sure that `rpm-ostree rebase` tests the
arguments passed in.

integration-tests/Earthfile

@@ -66,8 +66,8 @@ rebase:
 
 upgrade:
 	FROM +test-base
-	RUN mkdir -p /etc/bluebuild && touch /etc/bluebuild/cli_test.tar.gz
 
+	RUN mkdir -p /etc/bluebuild && touch $BB_TEST_LOCAL_IMAGE
 	RUN bluebuild -vv upgrade recipes/recipe.yml
 
 secureblue-base:
@@ -88,6 +88,7 @@ legacy-base:
 
 test-base:
 	FROM ../+blue-build-cli-alpine
+	ENV BB_TEST_LOCAL_IMAGE=/etc/bluebuild/cli_test.tar.gz
 	ENV CLICOLOR_FORCE=1
 
 	COPY ./mock-scripts/ /usr/bin/

integration-tests/mock-scripts/rpm-ostree

@@ -1,3 +1,19 @@
 #!/bin/sh
 
+set -euo pipefail
+
 echo 'Running rpm-ostree'
+
+if [ "$1" = "rebase" ]; then
+  if [ "$2" = "ostree-unverified-image:oci-archive:$BB_TEST_LOCAL_IMAGE" ]; then
+    echo "Rebased to local image $BB_TEST_LOCAL_IMAGE"
+  else
+   echo "Failed to rebase"
+   exit 1
+  fi
+elif [ "$1" = "upgrade" ]; then
+  echo "Performing upgrade for $BB_TEST_LOCAL_IMAGE"
+else
+  echo "Arg $1 is not recognized"
+  exit 1
+fi