[master] c8d0781df Stabilise r02020.vtc

[Martin Blix Grydeland]

commit c8d0781df30107481b3b199995973eee547dd034
Author: Martin Blix Grydeland <martin at varnish-software.com>
Date:   Wed Sep 1 17:52:29 2021 +0200

    Stabilise r02020.vtc
    
    This makes use of the fact that Varnish will always send a session window
    update immediately when receiving a data frame. The four rxwinup before
    barrier sync on stream 0 matches up with the four txdata frames sent early
    on the stream, and makes sure that the session thread has exhausted its
    send window completely before opening up and starting to consume rxbuf
    data by unblocking the client thread stuck in vcl_recv. From that point on
    window updates will also be sent on the stream.

diff --git a/bin/varnishtest/tests/t02020.vtc b/bin/varnishtest/tests/t02020.vtc
index 77738e17f..6a2ace287 100644
--- a/bin/varnishtest/tests/t02020.vtc
+++ b/bin/varnishtest/tests/t02020.vtc
@@ -1,6 +1,6 @@
 varnishtest "H/2 received data frames with padding"
 
-barrier b1 sock 2
+barrier b1 sock 3
 
 server s1 {
 	rxreq
@@ -34,7 +34,26 @@ client c1 {
 		txdata -data abcde -padlen 1
 		rxresp
 		expect resp.status == 200
-	} -run
+	} -start
+} -run
+
+client c2 {
+	# This makes use of the fact that Varnish will always send a
+	# session window update immediately when receiving a data
+	# frame. The four rxwinup before barrier sync on stream 0 matches
+	# up with the four txdata frames sent early on the stream, and
+	# makes sure that the session thread has exhausted its send window
+	# completely before opening up and starting to consume rxbuf data
+	# by unblocking the client thread stuck in vcl_recv. From that
+	# point on window updates will also be sent on the stream.
+
+	stream 0 {
+		rxwinup
+		rxwinup
+		rxwinup
+		rxwinup
+		barrier b1 sync
+	} -start
 
 	stream 3 {
 		txreq -req POST -url /3 -hdr "content-length" "131072" -nostrend
@@ -55,12 +74,14 @@ client c1 {
 		txdata -datalen 672
 		rxresp
 		expect resp.status == 200
-	} -run
+	} -start
+} -run
 
+client c3 {
 	stream 5 {
 		txreq -req POST -url /5 -nostrend
 		txdata -data a -padlen 255
 		rxresp
 		expect resp.status == 200
-	} -run
+	} -start
 } -run