Merge branch 'fix-23-image' into 'master'

fix CI ruby 2.3 build which could not download iptables package

See merge request os85/httpx!248

integration_tests/webmock_test.rb

@@ -204,6 +204,16 @@ class WebmockTest < Minitest::Test
     WebMock.disable_net_connect!
   end
 
+  def test_webmock_disable_after_enable
+    WebMock.disable!
+
+    # WebMock is disabled so this will make a real http request
+    http_request(:get, "http://#{httpbin}")
+
+    # WebMock is disabled so it should not have registered the request
+    assert_not_requested(:get, "http://#{httpbin}")
+  end
+
   private
 
   def assert_raise_with_message(e, message, &block)

lib/httpx/adapters/webmock.rb

@@ -122,7 +122,7 @@ module WebMock
 
       class << self
         def enable!
-          @original_session = HTTPX::Session
+          @original_session ||= HTTPX::Session
 
           webmock_session = HTTPX.plugin(Plugin)
 

test/support/ci/build.sh

@@ -16,8 +16,10 @@ if [[ "$RUBY_ENGINE" = "truffleruby" ]]; then
 elif [[ "$RUBY_PLATFORM" = "java" ]]; then
   apt-get update && apt-get install -y build-essential iptables iproute2 file idn2 git
 elif [[ ${RUBY_VERSION:0:3} = "2.3" ]]; then
-  # installing custom openssl
+  echo "deb http://archive.debian.org/debian stretch main contrib non-free" > /etc/apt/sources.list
   apt-get update && apt-get install -y iptables iproute2 iptables-nftables-compat libmagic-dev shared-mime-info # openssl=1.0.2l openssl-dev=1.0.2l
+  IPTABLES=iptables
+  # installing custom openssl
   wget http://deb.debian.org/debian/pool/main/o/openssl1.0/libssl1.0.2_1.0.2u-1~deb9u1_amd64.deb
   dpkg -i libssl1.0.2_1.0.2u-1~deb9u1_amd64.deb
   wget http://deb.debian.org/debian/pool/main/o/openssl1.0/libssl1.0-dev_1.0.2u-1~deb9u1_amd64.deb