test: use numstat instead of diffstat in binary-diff test

git's --stat output is intended for humans and since v1.7.9.2~13
(2012-02-01) varies by locale.  The tests in this script using "apply
--stat" are meant to check two things:

 - how binary file changes are accounted for and printed in
   git's diffstat format

 - that "git apply" can parse the various forms of binary diff

Split these two kinds of check into separate tests, and use --numstat
instead of --stat in the latter.  This way, we lose less test coverage
when git is being run without writing its output in the C locale (for
example because GETTEXT_POISON is enabled) and there are fewer tests
to change if the --stat output needs to be tweaked again.

While at it, use commands separated by && that read and write to
temporary files in place of pipelines so segfaults and other failures
in the upstream of the processing pipeline don't get hidden.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t4012-diff-binary.sh

@@ -8,6 +8,13 @@ test_description='Binary diff and apply
 
 . ./test-lib.sh
 
+cat >expect.binary-numstat <<\EOF
+1	1	a
+-	-	b
+1	1	c
+-	-	d
+EOF
+
 test_expect_success 'prepare repository' \
 	'echo AIT >a && echo BIT >b && echo CIT >c && echo DIT >d &&
 	 git update-index --add a b c d &&
@@ -23,13 +30,23 @@ cat > expected <<\EOF
  d |  Bin
  4 files changed, 2 insertions(+), 2 deletions(-)
 EOF
-test_expect_success 'diff without --binary' \
-	'git diff | git apply --stat --summary >current &&
-	 test_i18ncmp expected current'
+test_expect_success '"apply --stat" output for binary file change' '
+	git diff >diff &&
+	git apply --stat --summary <diff >current &&
+	test_i18ncmp expected current
+'
 
-test_expect_success 'diff with --binary' \
-	'git diff --binary | git apply --stat --summary >current &&
-	 test_i18ncmp expected current'
+test_expect_success 'apply --numstat notices binary file change' '
+	git diff >diff &&
+	git apply --numstat <diff >current &&
+	test_cmp expect.binary-numstat current
+'
+
+test_expect_success 'apply --numstat understands diff --binary format' '
+	git diff --binary >diff &&
+	git apply --numstat <diff >current &&
+	test_cmp expect.binary-numstat current
+'
 
 # apply needs to be able to skip the binary material correctly
 # in order to report the line number of a corrupt patch.