ruby: Run tests one at a time, instead of in parallel.

diff --git a/ruby/run-ruby-tests b/ruby/run-ruby-tests
index 6bf898b..643bff9 100755 (executable)
--- a/ruby/run-ruby-tests
+++ b/ruby/run-ruby-tests
@@ -18,4 +18,10 @@
 
 set -e
 
-rake test "$@"
+# Run them one at a time, otherwise rake runs them in parallel (which
+# is bound to fail because they all use a single test image file).
+
+for f in tests/tc_*.rb; do
+    echo rake test "$@" TEST="$f"
+    rake test "$@" TEST="$f"
+done