autotools: show test failure diff

This helps investigating issues, especially spurious errors only
happening during CI like the failure of "hardlink/options-maximum-size-8192"

diff --git a/tests/Makemodule.am b/tests/Makemodule.am
index 31cf70f42d27513b54863c8ff79933424aadcead..d5422bebf5cd7a3d4d49601854ca3c81d308344c 100644 (file)
--- a/tests/Makemodule.am
+++ b/tests/Makemodule.am
@@ -13,7 +13,7 @@ clean-local-tests:
 
 CLEAN_LOCALS += clean-local-tests
 
-TESTS_OPTIONS = --nonroot
+TESTS_OPTIONS = --nonroot --show-diff
 TESTS_PARALLEL = --parallel
 TESTS_COMMAND = $(top_srcdir)/tests/run.sh \
        --srcdir=$(abs_top_srcdir) \