tests: use "env" to run commands with temporary env-var settings

Ordinarily, we would say "VAR=VAL command" to execute a tested
command with environment variable(s) set only for that command.
This however does not work if 'command' is a shell function (most
notably 'test_must_fail'); the result of the assignment is retained
and affects later commands.

To avoid this, we used to assign and export environment variables
and run such a test in a subshell, like so:

        (
                VAR=VAL && export VAR &&
                test_must_fail git command to be tested
        )

But with "env" utility, we should be able to say:

        test_must_fail env VAR=VAL git command to be tested

which is much shorter and easier to read.

Signed-off-by: David Tran <unsignedzero@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1300-repo-config.sh

@@ -961,24 +961,15 @@ test_expect_success SYMLINKS 'symlinked configuration' '
 '
 
 test_expect_success 'nonexistent configuration' '
-	(
-		GIT_CONFIG=doesnotexist &&
-		export GIT_CONFIG &&
-		test_must_fail git config --list &&
-		test_must_fail git config test.xyzzy
-	)
+	test_must_fail env GIT_CONFIG=doesnotexist git config --list &&
+	test_must_fail env GIT_CONFIG=doesnotexist git config test.xyzzy
 '
 
 test_expect_success SYMLINKS 'symlink to nonexistent configuration' '
 	ln -s doesnotexist linktonada &&
 	ln -s linktonada linktolinktonada &&
-	(
-		GIT_CONFIG=linktonada &&
-		export GIT_CONFIG &&
-		test_must_fail git config --list &&
-		GIT_CONFIG=linktolinktonada &&
-		test_must_fail git config --list
-	)
+	test_must_fail env GIT_CONFIG=linktonada git config --list &&
+	test_must_fail env GIT_CONFIG=linktolinktonada git config --list
 '
 
 test_expect_success 'check split_cmdline return' "

t/t1510-repo-setup.sh

@@ -777,9 +777,7 @@ test_expect_success '#30: core.worktree and core.bare conflict (gitfile version)
 	setup_repo 30 "$here/30" gitfile true &&
 	(
 		cd 30 &&
-		GIT_DIR=.git &&
-		export GIT_DIR &&
-		test_must_fail git symbolic-ref HEAD 2>result
+		test_must_fail env GIT_DIR=.git git symbolic-ref HEAD 2>result
 	) &&
 	grep "core.bare and core.worktree" 30/result
 '

t/t3200-branch.sh

@@ -849,23 +849,15 @@ test_expect_success 'detect typo in branch name when using --edit-description' '
 	write_script editor <<-\EOF &&
 		echo "New contents" >"$1"
 	EOF
-	(
-		EDITOR=./editor &&
-		export EDITOR &&
-		test_must_fail git branch --edit-description no-such-branch
-	)
+	test_must_fail env EDITOR=./editor git branch --edit-description no-such-branch
 '
 
 test_expect_success 'refuse --edit-description on unborn branch for now' '
 	write_script editor <<-\EOF &&
 		echo "New contents" >"$1"
 	EOF
 	git checkout --orphan unborn &&
-	(
-		EDITOR=./editor &&
-		export EDITOR &&
-		test_must_fail git branch --edit-description
-	)
+	test_must_fail env EDITOR=./editor git branch --edit-description
 '
 
 test_expect_success '--merged catches invalid object names' '

t/t3301-notes.sh

@@ -17,7 +17,7 @@ GIT_EDITOR=./fake_editor.sh
 export GIT_EDITOR
 
 test_expect_success 'cannot annotate non-existing HEAD' '
-	(MSG=3 && export MSG && test_must_fail git notes add)
+	test_must_fail env MSG=3 git notes add
 '
 
 test_expect_success setup '
@@ -32,22 +32,16 @@ test_expect_success setup '
 '
 
 test_expect_success 'need valid notes ref' '
-	(MSG=1 GIT_NOTES_REF=/ && export MSG GIT_NOTES_REF &&
-	 test_must_fail git notes add) &&
-	(MSG=2 GIT_NOTES_REF=/ && export MSG GIT_NOTES_REF &&
-	 test_must_fail git notes show)
+	test_must_fail env MSG=1 GIT_NOTES_REF=/ git notes show &&
+	test_must_fail env MSG=2 GIT_NOTES_REF=/ git notes show
 '
 
 test_expect_success 'refusing to add notes in refs/heads/' '
-	(MSG=1 GIT_NOTES_REF=refs/heads/bogus &&
-	 export MSG GIT_NOTES_REF &&
-	 test_must_fail git notes add)
+	test_must_fail env MSG=1 GIT_NOTES_REF=refs/heads/bogus git notes add
 '
 
 test_expect_success 'refusing to edit notes in refs/remotes/' '
-	(MSG=1 GIT_NOTES_REF=refs/remotes/bogus &&
-	 export MSG GIT_NOTES_REF &&
-	 test_must_fail git notes edit)
+	test_must_fail env MSG=1 GIT_NOTES_REF=refs/heads/bogus git notes edit
 '
 
 # 1 indicates caught gracefully by die, 128 means git-show barked
@@ -838,11 +832,7 @@ test_expect_success 'create note from non-existing note with "git notes add -c"
 	git add a10 &&
 	test_tick &&
 	git commit -m 10th &&
-	(
-		MSG="yet another note" &&
-		export MSG &&
-		test_must_fail git notes add -c deadbeef
-	) &&
+	test_must_fail env MSG="yet another note" git notes add -c deadbeef &&
 	test_must_fail git notes list HEAD
 '
 

t/t3404-rebase-interactive.sh

@@ -102,12 +102,8 @@ test_expect_success 'rebase -i with the exec command runs from tree root' '
 
 test_expect_success 'rebase -i with the exec command checks tree cleanness' '
 	git checkout master &&
-	(
 	set_fake_editor &&
-	FAKE_LINES="exec_echo_foo_>file1 1" &&
-	export FAKE_LINES &&
-	test_must_fail git rebase -i HEAD^
-	) &&
+	test_must_fail env FAKE_LINES="exec_echo_foo_>file1 1" git rebase -i HEAD^ &&
 	test_cmp_rev master^ HEAD &&
 	git reset --hard &&
 	git rebase --continue
@@ -116,12 +112,9 @@ test_expect_success 'rebase -i with the exec command checks tree cleanness' '
 test_expect_success 'rebase -i with exec of inexistent command' '
 	git checkout master &&
 	test_when_finished "git rebase --abort" &&
-	(
 	set_fake_editor &&
-	FAKE_LINES="exec_this-command-does-not-exist 1" &&
-	export FAKE_LINES &&
-	test_must_fail git rebase -i HEAD^ >actual 2>&1
-	) &&
+	test_must_fail env FAKE_LINES="exec_this-command-does-not-exist 1" \
+	git rebase -i HEAD^ >actual 2>&1 &&
 	! grep "Maybe git-rebase is broken" actual
 '
 
@@ -375,11 +368,7 @@ test_expect_success 'commit message used after conflict' '
 	git checkout -b conflict-fixup conflict-branch &&
 	base=$(git rev-parse HEAD~4) &&
 	set_fake_editor &&
-	(
-		FAKE_LINES="1 fixup 3 fixup 4" &&
-		export FAKE_LINES &&
-		test_must_fail git rebase -i $base
-	) &&
+	test_must_fail env FAKE_LINES="1 fixup 3 fixup 4" git rebase -i $base &&
 	echo three > conflict &&
 	git add conflict &&
 	FAKE_COMMIT_AMEND="ONCE" EXPECT_HEADER_COUNT=2 \
@@ -394,11 +383,7 @@ test_expect_success 'commit message retained after conflict' '
 	git checkout -b conflict-squash conflict-branch &&
 	base=$(git rev-parse HEAD~4) &&
 	set_fake_editor &&
-	(
-		FAKE_LINES="1 fixup 3 squash 4" &&
-		export FAKE_LINES &&
-		test_must_fail git rebase -i $base
-	) &&
+	test_must_fail env FAKE_LINES="1 fixup 3 squash 4" git rebase -i $base &&
 	echo three > conflict &&
 	git add conflict &&
 	FAKE_COMMIT_AMEND="TWICE" EXPECT_HEADER_COUNT=2 \
@@ -469,11 +454,7 @@ test_expect_success 'interrupted squash works as expected' '
 	git checkout -b interrupted-squash conflict-branch &&
 	one=$(git rev-parse HEAD~3) &&
 	set_fake_editor &&
-	(
-		FAKE_LINES="1 squash 3 2" &&
-		export FAKE_LINES &&
-		test_must_fail git rebase -i HEAD~3
-	) &&
+	test_must_fail env FAKE_LINES="1 squash 3 2" git rebase -i HEAD~3 &&
 	(echo one; echo two; echo four) > conflict &&
 	git add conflict &&
 	test_must_fail git rebase --continue &&
@@ -487,11 +468,7 @@ test_expect_success 'interrupted squash works as expected (case 2)' '
 	git checkout -b interrupted-squash2 conflict-branch &&
 	one=$(git rev-parse HEAD~3) &&
 	set_fake_editor &&
-	(
-		FAKE_LINES="3 squash 1 2" &&
-		export FAKE_LINES &&
-		test_must_fail git rebase -i HEAD~3
-	) &&
+	test_must_fail env FAKE_LINES="3 squash 1 2" git rebase -i HEAD~3 &&
 	(echo one; echo four) > conflict &&
 	git add conflict &&
 	test_must_fail git rebase --continue &&
@@ -528,11 +505,7 @@ test_expect_success 'aborted --continue does not squash commits after "edit"' '
 	FAKE_LINES="edit 1" git rebase -i HEAD^ &&
 	echo "edited again" > file7 &&
 	git add file7 &&
-	(
-		FAKE_COMMIT_MESSAGE=" " &&
-		export FAKE_COMMIT_MESSAGE &&
-		test_must_fail git rebase --continue
-	) &&
+	test_must_fail env FAKE_COMMIT_MESSAGE=" " git rebase --continue &&
 	test $old = $(git rev-parse HEAD) &&
 	git rebase --abort
 '
@@ -547,23 +520,15 @@ test_expect_success 'auto-amend only edited commits after "edit"' '
 	echo "and again" > file7 &&
 	git add file7 &&
 	test_tick &&
-	(
-		FAKE_COMMIT_MESSAGE="and again" &&
-		export FAKE_COMMIT_MESSAGE &&
-		test_must_fail git rebase --continue
-	) &&
+	test_must_fail env FAKE_COMMIT_MESSAGE="and again" git rebase --continue &&
 	git rebase --abort
 '
 
 test_expect_success 'clean error after failed "exec"' '
 	test_tick &&
 	test_when_finished "git rebase --abort || :" &&
 	set_fake_editor &&
-	(
-		FAKE_LINES="1 exec_false" &&
-		export FAKE_LINES &&
-		test_must_fail git rebase -i HEAD^
-	) &&
+	test_must_fail env FAKE_LINES="1 exec_false" git rebase -i HEAD^ &&
 	echo "edited again" > file7 &&
 	git add file7 &&
 	test_must_fail git rebase --continue 2>error &&
@@ -947,12 +912,8 @@ test_expect_success 'rebase -i --root retain root commit author and message' '
 
 test_expect_success 'rebase -i --root temporary sentinel commit' '
 	git checkout B &&
-	(
-		set_fake_editor &&
-		FAKE_LINES="2" &&
-		export FAKE_LINES &&
-		test_must_fail git rebase -i --root
-	) &&
+	set_fake_editor &&
+	test_must_fail env FAKE_LINES="2" git rebase -i --root &&
 	git cat-file commit HEAD | grep "^tree 4b825dc642cb" &&
 	git rebase --abort
 '
@@ -1042,11 +1003,7 @@ test_expect_success 'rebase -i error on commits with \ in message' '
 	test_when_finished "git rebase --abort; git reset --hard $current_head; rm -f error" &&
 	test_commit TO-REMOVE will-conflict old-content &&
 	test_commit "\temp" will-conflict new-content dummy &&
-	(
-	EDITOR=true &&
-	export EDITOR &&
-	test_must_fail git rebase -i HEAD^ --onto HEAD^^ 2>error
-	) &&
+	test_must_fail env EDITOR=true git rebase -i HEAD^ --onto HEAD^^ 2>error &&
 	test_expect_code 1 grep  "	emp" error
 '
 

t/t3413-rebase-hook.sh

@@ -118,11 +118,7 @@ test_expect_success 'pre-rebase hook stops rebase (1)' '
 test_expect_success 'pre-rebase hook stops rebase (2)' '
 	git checkout test &&
 	git reset --hard side &&
-	(
-		EDITOR=:
-		export EDITOR
-		test_must_fail git rebase -i master
-	) &&
+	test_must_fail env EDITOR=: git rebase -i master &&
 	test "z$(git symbolic-ref HEAD)" = zrefs/heads/test &&
 	test 0 = $(git rev-list HEAD...side | wc -l)
 '

t/t4014-format-patch.sh

@@ -764,22 +764,14 @@ test_expect_success 'format-patch --signature="" suppresses signatures' '
 
 test_expect_success TTY 'format-patch --stdout paginates' '
 	rm -f pager_used &&
-	(
-		GIT_PAGER="wc >pager_used" &&
-		export GIT_PAGER &&
-		test_terminal git format-patch --stdout --all
-	) &&
+	test_terminal env GIT_PAGER="wc >pager_used" git format-patch --stdout --all &&
 	test_path_is_file pager_used
 '
 
  test_expect_success TTY 'format-patch --stdout pagination can be disabled' '
 	rm -f pager_used &&
-	(
-		GIT_PAGER="wc >pager_used" &&
-		export GIT_PAGER &&
-		test_terminal git --no-pager format-patch --stdout --all &&
-		test_terminal git -c "pager.format-patch=false" format-patch --stdout --all
-	) &&
+	test_terminal env GIT_PAGER="wc >pager_used" git --no-pager format-patch --stdout --all &&
+	test_terminal env GIT_PAGER="wc >pager_used" git -c "pager.format-patch=false" format-patch --stdout --all &&
 	test_path_is_missing pager_used &&
 	test_path_is_missing .git/pager_used
 '

t/t5305-include-tag.sh

@@ -45,9 +45,7 @@ test_expect_success 'unpack objects' '
 test_expect_success 'check unpacked result (have commit, no tag)' '
 	git rev-list --objects $commit >list.expect &&
 	(
-		GIT_DIR=clone.git &&
-		export GIT_DIR &&
-		test_must_fail git cat-file -e $tag &&
+		test_must_fail env GIT_DIR=clone.git git cat-file -e $tag &&
 		git rev-list --objects $commit
 	) >list.actual &&
 	test_cmp list.expect list.actual

t/t5602-clone-remote-exec.sh

@@ -12,21 +12,14 @@ test_expect_success setup '
 '
 
 test_expect_success 'clone calls git upload-pack unqualified with no -u option' '
-	(
-		GIT_SSH=./not_ssh &&
-		export GIT_SSH &&
-		test_must_fail git clone localhost:/path/to/repo junk
-	) &&
+	test_must_fail env GIT_SSH=./not_ssh git clone localhost:/path/to/repo junk &&
 	echo "localhost git-upload-pack '\''/path/to/repo'\''" >expected &&
 	test_cmp expected not_ssh_output
 '
 
 test_expect_success 'clone calls specified git upload-pack with -u option' '
-	(
-		GIT_SSH=./not_ssh &&
-		export GIT_SSH &&
-		test_must_fail git clone -u ./something/bin/git-upload-pack localhost:/path/to/repo junk
-	) &&
+	test_must_fail env GIT_SSH=./not_ssh \
+		git clone -u ./something/bin/git-upload-pack localhost:/path/to/repo junk &&
 	echo "localhost ./something/bin/git-upload-pack '\''/path/to/repo'\''" >expected &&
 	test_cmp expected not_ssh_output
 '

t/t5801-remote-helpers.sh

@@ -218,10 +218,8 @@ test_expect_success 'proper failure checks for fetching' '
 '
 
 test_expect_success 'proper failure checks for pushing' '
-	(GIT_REMOTE_TESTGIT_FAILURE=1 &&
-	export GIT_REMOTE_TESTGIT_FAILURE &&
-	cd local &&
-	test_must_fail git push --all
+	(cd local &&
+	test_must_fail env GIT_REMOTE_TESTGIT_FAILURE=1 git push --all
 	)
 '
 

t/t6006-rev-list-format.sh

@@ -190,12 +190,9 @@ test_expect_success '%C(auto) respects --no-color' '
 '
 
 test_expect_success TTY '%C(auto) respects --color=auto (stdout is tty)' '
-	(
-		TERM=vt100 && export TERM &&
-		test_terminal \
-			git log --format=$AUTO_COLOR -1 --color=auto >actual &&
-		has_color actual
-	)
+	test_terminal env TERM=vt100 \
+		git log --format=$AUTO_COLOR -1 --color=auto >actual &&
+	has_color actual
 '
 
 test_expect_success '%C(auto) respects --color=auto (stdout not tty)' '