[Bug-tar] tests/truncate.at

[Solar Designer]

Sergey,

Here's a patch to tests/truncate.at for its inherent yet undesirable
race condition to be less likely triggered, and to use less disk space
(2 MB instead of 500 MB).  The patch is against 1.23, but it appears to
be relevant and valid for 1.25 as well.

--- tar-1.23.orig/tests/truncate.at     2010-01-26 11:30:21 +0000
+++ tar-1.23/tests/truncate.at  2010-12-04 05:38:58 +0000
@@ -30,13 +30,12 @@
 AT_KEYWORDS([truncate filechange])
 
 AT_TAR_CHECK([
-genfile --file foo --length 50000k
+genfile --file foo --length 200k
 genfile --file baz
-genfile --run --checkpoint 10 --length 49995k --truncate foo -- tar 
--checkpoint -vcf bar foo baz
+genfile --run --checkpoint 10 --length 195k --truncate foo -- tar --checkpoint 
--checkpoint-action=echo --checkpoint-action=sleep=1 -vcf bar foo baz
 echo Exit status: $?
 echo separator
-sleep 1
-genfile --file foo --seek 49995k --length 5k --pattern=zeros
+genfile --file foo --seek 195k --length 5k --pattern=zeros
 tar dvf bar],
 [1],
 [foo

Without this patch, our package of tar sometimes fails to build (we run
tests on package builds).  Here's how the test fails (before the patch):

--- -   2010-12-04 08:06:08 +0300
+++ /usr/src/world/t/tar-1.23/tests/testsuite.dir/at-stderr     2010-12-04 
08:06:08 +0300
@@ -1,2 +1 @@
-tar: foo: File shrank by 5120 bytes; padding with zeros
 
--- -   2010-12-04 08:06:08 +0300
+++ /usr/src/world/t/tar-1.23/tests/testsuite.dir/at-stdout     2010-12-04 
08:06:08 +0300
@@ -1,8 +1,9 @@
 foo
 baz
-Exit status: 1
+Exit status: 0
 separator
 foo
 foo: Mod time differs
+foo: Contents differ
 baz

The above test failure was for my test build of clean 1.23 (without any
of our patches), but on the same system that sometimes exhibits the
problem building the package.  I had to run "make check" several times
to trigger the problem.

Alexander