Add tests for 'detect-external-ip' script of Docker image

docker/coturn/tests/main.bats

@@ -125,3 +125,76 @@
   [ "$status" -eq 0 ]
   [ ! "$output" = '' ]
 }
+
+
+@test "detect-external-ip is present" {
+  run docker run --rm --platform $PLATFORM --entrypoint sh $IMAGE -c \
+    'which detect-external-ip'
+  [ "$status" -eq 0 ]
+}
+
+@test "detect-external-ip runs ok" {
+  run docker run --rm --platform $PLATFORM --entrypoint sh $IMAGE -c \
+    'detect-external-ip'
+  [ "$status" -eq 0 ]
+}
+
+@test "detect-external-ip returns valid IPv4" {
+  run docker run --rm --platform $PLATFORM --entrypoint sh $IMAGE -c \
+    'detect-external-ip --ipv4'
+  [ "$status" -eq 0 ]
+
+  run validate_ipv4 "$output"
+  [ "$status" -eq 0 ]
+}
+
+@test "detect-external-ip returns valid IPv6" {
+  run docker run --rm --platform $PLATFORM --entrypoint sh $IMAGE -c \
+    'detect-external-ip --ipv6'
+  [ "$status" -eq 0 ]
+
+  run validate_ipv6 "$output"
+  [ "$status" -eq 0 ]
+}
+
+@test "detect-external-ip returns IPv4 by default" {
+  run docker run --rm --platform $PLATFORM --entrypoint sh $IMAGE -c \
+    'detect-external-ip --ipv4'
+  [ "$status" -eq 0 ]
+
+  run validate_ipv4 "$output"
+  [ "$status" -eq 0 ]
+}
+
+
+#
+# Helpers
+#
+
+# Tests the IP address to be a valid IPv4 address.
+function validate_ipv4() {
+  local ip=$1
+  local stat=1
+
+  if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
+    OIFS=$IFS
+    IFS='.'
+    ip=($ip)
+    IFS=$OIFS
+    [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
+    && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
+    stat=$?
+  fi
+  return $stat
+}
+
+# Tests the IP address to be a valid IPv6 address.
+function validate_ipv6() {
+  local ip=$1
+  local stat=1
+
+  if [[ $ip =~ ^([0-9a-fA-F]{0,4}:){1,7}[0-9a-fA-F]{0,4}$ ]]; then
+    stat=0
+  fi
+  return $stat
+}