Added test for fcrepo6 file backend.

fcrepo6/tests/ServiceStartsWithBackendFile/build.gradle.kts

@@ -0,0 +1,6 @@
+import plugins.TestsPlugin.DockerComposeUp
+
+tasks.named<DockerComposeUp>("test") {
+    // Remove 143 when https://github.com/Islandora-Devops/isle-buildkit/issues/269 is resolved.
+    expectExitCodes("fcrepo6", 0, 143)
+}

fcrepo6/tests/ServiceStartsWithBackendFile/docker-compose.yml

@@ -0,0 +1,24 @@
+# file: docker-compose.yml
+#
+# Tests that the base values for database environment variables can be
+# overridden by prefixing them.
+#
+# `base/rootfs/etc/cont-init.d/00-container-environment-00-init.sh`
+version: "3.8"
+
+x-common: &common
+  restart: "no"
+
+name: fcrepo6-servicestartswithbackendfile
+services:
+  activemq:
+    <<: *common
+    image: ${ACTIVEMQ:-islandora/activemq:local}
+  fcrepo6:
+    volumes:
+      - ./test.sh:/test.sh # Test to run.
+    command:
+      - /test.sh # Run test and exit.
+    image: ${FCREPO6:-islandora/fcrepo6:local}
+    depends_on:
+      - activemq

fcrepo6/tests/ServiceStartsWithBackendFile/test.sh

@@ -0,0 +1,15 @@
+#!/command/with-contenv bash
+# shellcheck shell=bash
+
+# shellcheck disable=SC1091
+source /usr/local/share/isle/utilities.sh
+
+# Wait for fcrepo to start.
+wait_20x http://localhost:8080/fcrepo/rest
+
+# Add some content.
+object=$(curl --fail -X POST -H "Authorization: Bearer islandora" -H "Content-Type:text/plain" "http://localhost:8080/fcrepo/rest" 2>/dev/null)
+echo "Create Object: $object"
+
+# All tests were successful
+exit 0