diff --git a/.travis.yml b/.travis.yml
index 5af35eb..4745598 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,19 +10,20 @@ go:
 env:
   - MODE=interop CLIENT=boring
   - MODE=interop CLIENT=bogo
-  - MODE=interop CLIENT=tstclnt
+  - MODE=interop CLIENT=tstclnt # added while ZRTT=1 is broken
+  - MODE=interop CLIENT=picotls ZRTT=1
   - MODE=interop CLIENT=mint
   - MODE=gotest
+  - MODE=interop CLIENT=tstclnt ZRTT=1
   - MODE=interop CLIENT=boring REVISION=origin/master
-  - MODE=interop CLIENT=bogo REVISION=origin/master
-  - MODE=interop CLIENT=tstclnt REVISION=default
+  - MODE=interop CLIENT=tstclnt REVISION=default ZRTT=1
 
 matrix:
   fast_finish: true
   allow_failures:
     - env: MODE=interop CLIENT=boring REVISION=origin/master
-    - env: MODE=interop CLIENT=bogo REVISION=origin/master
-    - env: MODE=interop CLIENT=tstclnt REVISION=default
+    - env: MODE=interop CLIENT=tstclnt ZRTT=1 # tstclnt races and doesn't resend
+    - env: MODE=interop CLIENT=tstclnt REVISION=default ZRTT=1
     - env: MODE=interop CLIENT=mint # broken resumption client
 
 install:
@@ -31,7 +32,7 @@ install:
 
 script:
   - if [ "$MODE" = "interop" ]; then ./_dev/interop.sh RUN $CLIENT; fi
-  - if [ "$MODE" = "interop" ] && [ "$CLIENT" = "tstclnt" ]; then ./_dev/interop.sh 0-RTT $CLIENT; fi
+  - if [ "$MODE" = "interop" ] && [ "$ZRTT" = "1" ]; then ./_dev/interop.sh 0-RTT $CLIENT; fi
   - if [ "$MODE" = "gotest" ]; then ./_dev/go.sh test -race crypto/tls; fi
 
 after_script:
diff --git a/_dev/picotls/Dockerfile b/_dev/picotls/Dockerfile
new file mode 100644
index 0000000..d63b177
--- /dev/null
+++ b/_dev/picotls/Dockerfile
@@ -0,0 +1,21 @@
+FROM alpine
+
+RUN apk add --update \
+    git \
+    cmake \
+    build-base \
+    openssl-dev \
+    bash \
+  && rm -rf /var/cache/apk/*
+
+RUN git clone https://github.com/h2o/picotls
+
+ARG REVISION=a6c1c65
+RUN cd picotls && git fetch && git checkout $REVISION
+
+RUN cd picotls && git submodule update --init
+RUN cd picotls && cmake . && make
+
+ADD httpreq.txt /httpreq.txt
+ADD run.sh /run.sh
+ENTRYPOINT ["/run.sh"]
diff --git a/_dev/picotls/httpreq.txt b/_dev/picotls/httpreq.txt
new file mode 100644
index 0000000..e4e6ac1
--- /dev/null
+++ b/_dev/picotls/httpreq.txt
@@ -0,0 +1,5 @@
+GET / HTTP/1.1
+Host: example.com
+Connection: close
+
+
diff --git a/_dev/picotls/run.sh b/_dev/picotls/run.sh
new file mode 100755
index 0000000..e7e278c
--- /dev/null
+++ b/_dev/picotls/run.sh
@@ -0,0 +1,10 @@
+#! /bin/bash
+set -e
+
+IFS=':' read -ra ADDR <<< "$1"
+shift
+HOST="${ADDR[0]}"
+PORT="${ADDR[1]}"
+
+/picotls/cli -s /session -e "$@" $HOST $PORT < /httpreq.txt
+/picotls/cli -s /session -e "$@" $HOST $PORT < /httpreq.txt
diff --git a/handshake_client_test.go b/handshake_client_test.go
index c839926..083036a 100644
--- a/handshake_client_test.go
+++ b/handshake_client_test.go
@@ -68,8 +68,8 @@ func (i opensslInput) Read(buf []byte) (n int, err error) {
 // log message from a completed server handshake.
 type opensslOutputSink struct {
 	handshakeConfirmed chan struct{}
-	all                []byte
-	line               []byte
+	all               []byte
+	line              []byte
 }
 
 func newOpensslOutputSink() *opensslOutputSink {