integration: node removal for file discovery

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

test/integration/discovery/discovery_helpers.bash

@@ -4,13 +4,17 @@ load ../helpers
 
 # Returns true if all nodes have joined the swarm.
 function discovery_check_swarm_info() {
-	docker_swarm info | grep -q "Nodes: ${#HOSTS[@]}"
+	local total="$1"
+	[ -z "$total" ] && total="${#HOSTS[@]}"
+
+	docker_swarm info | grep -q "Nodes: $count"
 }
 
 # Returns true if all nodes have joined the discovery.
 function discovery_check_swarm_list() {
 	local joined=`swarm list "$1" | wc -l`
-	local total=${#HOSTS[@]}
+	local total="$2"
+	[ -z "$total" ] && total="${#HOSTS[@]}"
 
 	echo "${joined} out of ${total} hosts joined discovery"
 	[ "$joined" -eq "$total" ]

test/integration/discovery/file.bats

@@ -31,7 +31,7 @@ function setup_discovery_file() {
 	# Start 2 engines and register them in the file.
 	start_docker 2
 	setup_discovery_file
-	retry 5 1 discovery_check_swarm_list "$DISCOVERY"
+	discovery_check_swarm_list "$DISCOVERY"
 
 	# Then, start a manager and ensure it sees all the engines.
 	swarm_manage "$DISCOVERY"
@@ -49,10 +49,28 @@ function setup_discovery_file() {
 	# Add engines to the cluster and make sure it's picked up by swarm.
 	start_docker 2
 	setup_discovery_file
-	retry 5 1 discovery_check_swarm_list "$DISCOVERY"
+	discovery_check_swarm_list "$DISCOVERY"
 	retry 5 1 discovery_check_swarm_info
 }
 
+@test "file discovery: node removal" {
+	# The goal of this test is to ensure swarm can handle node removal.
+
+	# Start 2 engines and register them in the file.
+	start_docker 2
+	setup_discovery_file
+	discovery_check_swarm_list "$DISCOVERY"
+
+	# Then, start a manager and ensure it sees all the engines.
+	swarm_manage "$DISCOVERY"
+	retry 5 1 discovery_check_swarm_info
+
+	# Update the file with only one engine and see if swarm picks it up.
+	echo ${HOSTS[0]} > $DISCOVERY_FILE
+	discovery_check_swarm_list "$DISCOVERY" 1
+	retry 5 1 discovery_check_swarm_info 1
+}
+
 @test "file discovery: failure" {
 	# The goal of this test is to simulate a failure (file not available) and ensure discovery
 	# is resilient to it.
@@ -70,6 +88,6 @@ function setup_discovery_file() {
 	setup_discovery_file
 
 	# After a while, `join` and `manage` should see the file.
-	retry 5 1 discovery_check_swarm_list "$DISCOVERY"
+	discovery_check_swarm_list "$DISCOVERY"
 	retry 5 1 discovery_check_swarm_info
 }