Re-enable dedup, add test (closes #95)

testsuite/test-backup-dedup.sh

@@ -0,0 +1,23 @@
+set -e
+
+prepare
+run restic init
+
+# first backup without dedup
+run restic backup "${BASE}/fake-data"
+size=$(du -sm "$RESTIC_REPOSITORY" | cut -f1)
+debug "size before: $size"
+
+# second backup with dedup
+run restic backup "${BASE}/fake-data"
+size2=$(du -sm "$RESTIC_REPOSITORY" | cut -f1)
+debug "size after: $size2"
+
+# check if the repository hasn't grown more than 5%
+threshhold=$(($size+$size/20))
+debug "threshhold is $threshhold"
+if [[ "$size2" -gt "$threshhold" ]]; then
+    fail "dedup failed, repo grown more than 5%, before ${size}MiB after ${size2}MiB threshhold ${threshhold}MiB"
+fi
+
+cleanup