add a test to catch issue #1164
where `--test -m files*.lz4` would create a bunch of `files*` files.
`--test` should not create any file.
It turns out the bug was already fixed when #1164 was filled,
but it also shows that the CI system was blind to such issues when it happened.
The new test was run with `v1.9.3` and triggered an error, as expected.
diff --git a/tests/Makefile b/tests/Makefile
index 93a5581..62e364a 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -312,8 +312,14 @@
# compress multiple files, one of which is absent (must fail)
! $(LZ4) -f -m $(FPREFIX)-concat1 notHere $(FPREFIX)-concat2 # must fail : notHere not present
# test lz4-compressed file
+ $(RM) $(FPREFIX)-concat1 $(FPREFIX)-concat2
$(LZ4) -tm $(FPREFIX)-concat1.lz4
+ # ensure the test doesn't create artifact
+ test ! -f $(FPREFIX)-concat1 # must not create file artefact
+ # test multiple lz4-compressed file
$(LZ4) -tm $(FPREFIX)-concat1.lz4 $(FPREFIX)-concat2.lz4
+ test ! -f $(FPREFIX)-concat1 # must not create file artefact
+ test ! -f $(FPREFIX)-concat2 # must not create file artefact
# test multiple lz4 files, one of which is absent (must fail)
! $(LZ4) -tm $(FPREFIX)-concat1.lz4 notHere.lz4 $(FPREFIX)-concat2.lz4
@$(RM) $(FPREFIX)*
