t7005: sanitize test environment for subsequent tests

Some of the editor tests manipulate the environment or config in ways
that affect future tests, but those modifications are visible to future
tests and create a footgun for them.

Use test_config, subshells, single-command environment overrides, and
test helpers to automatically undo environment and config modifications
once finished.

Best-viewed-with: --ignore-all-space
Signed-off-by: D. Ben Knoble <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: benknoble

t/t7005-editor.sh

@@ -34,61 +34,57 @@ test_expect_success setup '
 	test_commit_message HEAD -m "$msg"
 '
 
-TERM=dumb
-export TERM
 test_expect_success 'dumb should error out when falling back on vi' '
-	test_must_fail git commit --amend
+	test_must_fail env TERM=dumb git commit --amend
 '
 
 test_expect_success 'dumb should prefer EDITOR to VISUAL' '
-	EDITOR=./e-EDITOR.sh &&
-	VISUAL=./e-VISUAL.sh &&
-	export EDITOR VISUAL &&
-	git commit --amend &&
+	TERM=dumb EDITOR=./e-EDITOR.sh VISUAL=./e-VISUAL.sh \
+		git commit --amend &&
 	test_commit_message HEAD -m "Edited by EDITOR"
 '
 
-TERM=vt100
-export TERM
 for i in $vi EDITOR VISUAL core_editor GIT_EDITOR
 do
-	echo "Edited by $i" >expect
-	unset EDITOR VISUAL GIT_EDITOR
-	git config --unset-all core.editor
-	case "$i" in
-	core_editor)
-		git config core.editor ./e-core_editor.sh
-		;;
-	[A-Z]*)
-		eval "$i=./e-$i.sh"
-		export $i
-		;;
-	esac
 	test_expect_success "Using $i" '
-		PATH="$PWD:$PATH" git commit --amend &&
-		test_commit_message HEAD expect
+		if test "$i" = core_editor
+		then
+			test_config core.editor ./e-core_editor.sh
+		fi &&
+		(
+			case "$i" in
+			[A-Z]*)
+				eval "$i=./e-$i.sh" &&
+				export $i
+				;;
+			esac &&
+			PATH="$PWD:$PATH" TERM=vt100 git commit --amend
+		) &&
+		test_commit_message HEAD -m "Edited by $i"
 	'
 done
 
-unset EDITOR VISUAL GIT_EDITOR
-git config --unset-all core.editor
-for i in $vi EDITOR VISUAL core_editor GIT_EDITOR
-do
-	echo "Edited by $i" >expect
-	case "$i" in
-	core_editor)
-		git config core.editor ./e-core_editor.sh
-		;;
-	[A-Z]*)
-		eval "$i=./e-$i.sh"
-		export $i
-		;;
-	esac
-	test_expect_success "Using $i (override)" '
-		PATH="$PWD:$PATH" git commit --amend &&
-		test_commit_message HEAD expect
-	'
-done
+test_expect_success 'Using editors with overrides' '
+	(
+		TERM=vt100 &&
+		export TERM &&
+		for i in $vi EDITOR VISUAL core_editor GIT_EDITOR
+		do
+			echo "Edited by $i" >expect &&
+			case "$i" in
+			core_editor)
+				git config core.editor ./e-core_editor.sh
+				;;
+			[A-Z]*)
+				eval "$i=./e-$i.sh" &&
+				export $i
+				;;
+			esac &&
+			PATH="$PWD:$PATH" git commit --amend &&
+			test_commit_message HEAD expect || exit 1
+		done
+	)
+'
 
 test_expect_success 'editor with a space' '
 	echo "echo space >\"\$1\"" >"e space.sh" &&
@@ -97,9 +93,8 @@ test_expect_success 'editor with a space' '
 	test_commit_message HEAD -m space
 '
 
-unset GIT_EDITOR
 test_expect_success 'core.editor with a space' '
-	git config core.editor \"./e\ space.sh\" &&
+	test_config core.editor \"./e\ space.sh\" &&
 	git commit --amend &&
 	test_commit_message HEAD -m space
 '