[PATCH 09/25] t: use test_might_fail for diff and grep

[Jeff King <peff@peff.net>]

Some tests run diff or grep to produce an output, and then
compare the output to an expected value. We know the exit
code we expect these processes to have (e.g., grep yields 0
if it produced output and 1 otherwise), so it would not make
the test wrong to look for it. But the difference between
their output and the expected output (e.g., shown by
test_cmp) is much more useful to somebody debugging the test
than the test just bailing out.

These tests break the &&-chain to skip the exit-code check
of the process. However, we can get the same effect by using
test_might_fail. Note that in some cases the test did use
"|| return 1", which meant the test was not wrong, but it
did fool --chain-lint.

Signed-off-by: Jeff King <peff@peff.net>
---
 t/t1002-read-tree-m-u-2way.sh | 8 ++++----
 t/t5550-http-fetch-dumb.sh    | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/t/t1002-read-tree-m-u-2way.sh b/t/t1002-read-tree-m-u-2way.sh
index fed877b..e3bf821 100755
--- a/t/t1002-read-tree-m-u-2way.sh
+++ b/t/t1002-read-tree-m-u-2way.sh
@@ -75,8 +75,8 @@ test_expect_success \
      echo yomin >yomin &&
      git update-index --add yomin &&
      read_tree_u_must_succeed -m -u $treeH $treeM &&
-     git ls-files --stage >4.out || return 1
-     git diff -U0 --no-index M.out 4.out >4diff.out
+     git ls-files --stage >4.out &&
+     test_might_fail git diff -U0 --no-index M.out 4.out >4diff.out &&
      compare_change 4diff.out expected &&
      check_cache_at yomin clean &&
      sum bozbar frotz nitfol >actual4.sum &&
@@ -94,8 +94,8 @@ test_expect_success \
      git update-index --add yomin &&
      echo yomin yomin >yomin &&
      read_tree_u_must_succeed -m -u $treeH $treeM &&
-     git ls-files --stage >5.out || return 1
-     git diff -U0 --no-index M.out 5.out >5diff.out
+     git ls-files --stage >5.out &&
+     test_might_fail git diff -U0 --no-index M.out 5.out >5diff.out &&
      compare_change 5diff.out expected &&
      check_cache_at yomin dirty &&
      sum bozbar frotz nitfol >actual5.sum &&
diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index 61e087e..3d11b7a 100755
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -184,8 +184,8 @@ test_expect_success 'fetch can handle previously-fetched .idx files' '
 '
 
 test_expect_success 'did not use upload-pack service' '
-	grep '/git-upload-pack' <"$HTTPD_ROOT_PATH"/access.log >act
-	: >exp
+	test_might_fail grep '/git-upload-pack' <"$HTTPD_ROOT_PATH"/access.log >act &&
+	: >exp &&
 	test_cmp exp act
 '
 
-- 
2.3.3.520.g3cfbb5d