[PATCH 16/29] t: use test_might_fail() instead of manipulating exit code manually

[Eric Sunshine <sunshine@sunshineco.com>]

These tests manually coerce the exit code of invoked commands to
"success" when they don't care if the command succeeds or fails since
failure of those commands should not cause the test to fail overall.
Such manual management predates the invention of test_might_fail().

An upcoming change will teach --chain-lint to check the &&-chain inside
subshells. This sort of manual exit code manipulation will trip up
--chain-lint due to the intentional break in the &&-chain. Therefore,
replace manual exit code management with test_might_fail() and a normal
&&-chain.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
---
 t/t1507-rev-parse-upstream.sh | 6 +++---
 t/t1700-split-index.sh        | 2 +-
 t/t4012-diff-binary.sh        | 6 ++----
 t/t5400-send-pack.sh          | 4 ++--
 4 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/t/t1507-rev-parse-upstream.sh b/t/t1507-rev-parse-upstream.sh
index 93c77eac45..349f6e10af 100755
--- a/t/t1507-rev-parse-upstream.sh
+++ b/t/t1507-rev-parse-upstream.sh
@@ -123,9 +123,9 @@ test_expect_success 'checkout -b new my-side@{u} forks from the same' '
 
 test_expect_success 'merge my-side@{u} records the correct name' '
 (
-	cd clone || exit
-	git checkout master || exit
-	git branch -D new ;# can fail but is ok
+	cd clone &&
+	git checkout master &&
+	test_might_fail git branch -D new &&
 	git branch -t new my-side@{u} &&
 	git merge -s ours new@{u} &&
 	git show -s --pretty=tformat:%s >actual &&
diff --git a/t/t1700-split-index.sh b/t/t1700-split-index.sh
index 1e81b33b2e..39133bcbc8 100755
--- a/t/t1700-split-index.sh
+++ b/t/t1700-split-index.sh
@@ -435,7 +435,7 @@ test_expect_success 'writing split index with null sha1 does not write cache tre
 	commit=$(git commit-tree $tree -p HEAD <msg) &&
 	git update-ref HEAD "$commit" &&
 	GIT_ALLOW_NULL_SHA1=1 git reset --hard &&
-	(test-tool dump-cache-tree >cache-tree.out || true) &&
+	test_might_fail test-tool dump-cache-tree >cache-tree.out &&
 	test_line_count = 0 cache-tree.out
 '
 
diff --git a/t/t4012-diff-binary.sh b/t/t4012-diff-binary.sh
index 0a8af76aab..6579c81216 100755
--- a/t/t4012-diff-binary.sh
+++ b/t/t4012-diff-binary.sh
@@ -102,10 +102,8 @@ test_expect_success 'apply binary patch' '
 
 test_expect_success 'diff --no-index with binary creation' '
 	echo Q | q_to_nul >binary &&
-	(: hide error code from diff, which just indicates differences
-	 git diff --binary --no-index /dev/null binary >current ||
-	 true
-	) &&
+	# hide error code from diff, which just indicates differences
+	test_might_fail git diff --binary --no-index /dev/null binary >current &&
 	rm binary &&
 	git apply --binary <current &&
 	echo Q >expected &&
diff --git a/t/t5400-send-pack.sh b/t/t5400-send-pack.sh
index 911eae1bf7..f1932ea431 100755
--- a/t/t5400-send-pack.sh
+++ b/t/t5400-send-pack.sh
@@ -86,7 +86,7 @@ test_expect_success 'push can be used to delete a ref' '
 test_expect_success 'refuse deleting push with denyDeletes' '
 	(
 	    cd victim &&
-	    ( git branch -D extra || : ) &&
+	    test_might_fail git branch -D extra &&
 	    git config receive.denyDeletes true &&
 	    git branch extra master
 	) &&
@@ -119,7 +119,7 @@ test_expect_success 'override denyDeletes with git -c receive-pack' '
 test_expect_success 'denyNonFastforwards trumps --force' '
 	(
 	    cd victim &&
-	    ( git branch -D extra || : ) &&
+	    test_might_fail git branch -D extra &&
 	    git config receive.denyNonFastforwards true
 	) &&
 	victim_orig=$(cd victim && git rev-parse --verify master) &&
-- 
2.18.0.419.gfe4b301394