t9001: enhance fake sendmail test harness

Previously, the fake.sendmail test harness would write its
output to a hardcoded file, allowing only a single message
to be tested. Instead, let's have it save the messages for
all of its invocations so that we can see which messages
were sent, and in which order.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t9001-send-email.sh

@@ -15,16 +15,22 @@ test_expect_success \
     'Setup helper tool' \
     '(echo "#!/bin/sh"
       echo shift
+      echo output=1
+      echo "while test -f commandline\$output; do output=\$((\$output+1)); done"
       echo for a
       echo do
       echo "  echo \"!\$a!\""
-      echo "done >commandline"
-      echo "cat > msgtxt"
+      echo "done >commandline\$output"
+      echo "cat > msgtxt\$output"
       ) >fake.sendmail &&
      chmod +x ./fake.sendmail &&
      git add fake.sendmail &&
      GIT_AUTHOR_NAME="A" git commit -a -m "Second."'
 
+clean_fake_sendmail() {
+	rm -f commandline* msgtxt*
+}
+
 test_expect_success 'Extract patches' '
     patches=`git format-patch -n HEAD^1`
 '
@@ -39,7 +45,7 @@ cat >expected <<\EOF
 EOF
 test_expect_success \
     'Verify commandline' \
-    'diff commandline expected'
+    'diff commandline1 expected'
 
 cat >expected-show-all-headers <<\EOF
 0001-Second.patch
@@ -82,7 +88,7 @@ z8=zzzzzzzz
 z64=$z8$z8$z8$z8$z8$z8$z8$z8
 z512=$z64$z64$z64$z64$z64$z64$z64$z64
 test_expect_success 'reject long lines' '
-	rm -f commandline &&
+	clean_fake_sendmail &&
 	cp $patches longline.patch &&
 	echo $z512$z512 >>longline.patch &&
 	! git send-email \
@@ -95,7 +101,7 @@ test_expect_success 'reject long lines' '
 '
 
 test_expect_success 'no patch was sent' '
-	! test -e commandline
+	! test -e commandline1
 '
 
 test_expect_success 'allow long lines with --no-validate' '
@@ -109,24 +115,26 @@ test_expect_success 'allow long lines with --no-validate' '
 '
 
 test_expect_success 'Invalid In-Reply-To' '
+	clean_fake_sendmail &&
 	git send-email \
 		--from="Example <nobody@example.com>" \
 		--to=nobody@example.com \
 		--in-reply-to=" " \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches
 		2>errors
-	! grep "^In-Reply-To: < *>" msgtxt
+	! grep "^In-Reply-To: < *>" msgtxt1
 '
 
 test_expect_success 'Valid In-Reply-To when prompting' '
+	clean_fake_sendmail &&
 	(echo "From Example <from@example.com>"
 	 echo "To Example <to@example.com>"
 	 echo ""
 	) | env GIT_SEND_EMAIL_NOTTY=1 git send-email \
 		--smtp-server="$(pwd)/fake.sendmail" \
 		$patches 2>errors &&
-	! grep "^In-Reply-To: < *>" msgtxt
+	! grep "^In-Reply-To: < *>" msgtxt1
 '
 
 test_done