t7500: make each piece more independent

These tests prepare the working tree & index state to have something
to be committed, and try a sequence of "test_must_fail git commit".
If an earlier one did not fail by a bug, a later one will fail for
a wrong reason (namely, "nothing to commit").

Give them "--allow-empty" to make sure that they would work even
when there is nothing to commit by accident.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: gitster

t/t7500-commit-template-squash-signoff.sh

@@ -42,41 +42,41 @@ test_expect_success 'nonexistent template file in config should return error' '
 	(
 		GIT_EDITOR="echo hello >\"\$1\"" &&
 		export GIT_EDITOR &&
-		test_must_fail git commit
+		test_must_fail git commit --allow-empty
 	)
 '
 
 # From now on we'll use a template file that exists.
 TEMPLATE="$PWD"/template
 
 test_expect_success 'unedited template should not commit' '
-	echo "template line" > "$TEMPLATE" &&
-	test_must_fail git commit --template "$TEMPLATE"
+	echo "template line" >"$TEMPLATE" &&
+	test_must_fail git commit --allow-empty --template "$TEMPLATE"
 '
 
 test_expect_success 'unedited template with comments should not commit' '
-	echo "# comment in template" >> "$TEMPLATE" &&
-	test_must_fail git commit --template "$TEMPLATE"
+	echo "# comment in template" >>"$TEMPLATE" &&
+	test_must_fail git commit --allow-empty --template "$TEMPLATE"
 '
 
 test_expect_success 'a Signed-off-by line by itself should not commit' '
 	(
 		test_set_editor "$TEST_DIRECTORY"/t7500/add-signed-off &&
-		test_must_fail git commit --template "$TEMPLATE"
+		test_must_fail git commit --allow-empty --template "$TEMPLATE"
 	)
 '
 
 test_expect_success 'adding comments to a template should not commit' '
 	(
 		test_set_editor "$TEST_DIRECTORY"/t7500/add-comments &&
-		test_must_fail git commit --template "$TEMPLATE"
+		test_must_fail git commit --allow-empty --template "$TEMPLATE"
 	)
 '
 
 test_expect_success 'adding real content to a template should commit' '
 	(
 		test_set_editor "$TEST_DIRECTORY"/t7500/add-content &&
-		git commit --template "$TEMPLATE"
+		git commit --allow-empty --template "$TEMPLATE"
 	) &&
 	commit_msg_is "template linecommit message"
 '