ci: add Docker E2E tests

Rakefile

@@ -28,6 +28,8 @@ hadolint_version = 'v2.8.0'
 trivy_version = 'v0.21.2'
 
 namespace :docker do
+  ci_image = 'cmur2/dyndnsd:ci'
+
   desc 'Lint Dockerfile'
   task :lint do
     sh "if [ ! -e ./hadolint ]; then wget -q -O ./hadolint https://github.com/hadolint/hadolint/releases/download/#{hadolint_version}/hadolint-Linux-x86_64; fi"
@@ -45,11 +47,35 @@ namespace :docker do
   task :scan do
     ver = trivy_version.gsub('v', '')
     sh "if [ ! -e ./trivy ]; then wget -q -O - https://github.com/aquasecurity/trivy/releases/download/v#{ver}/trivy_#{ver}_Linux-64bit.tar.gz | tar -xzf - trivy; fi"
-    sh './trivy cmur2/dyndnsd:ci'
+    sh "./trivy #{ci_image}"
+  end
+
+  desc 'End-to-end test the CI Docker image'
+  task :e2e do
+    sh <<~SCRIPT
+      echo -n '{}' > e2e/db.json
+      chmod a+w e2e/db.json
+    SCRIPT
+    sh "docker run -d --name=dyndnsd-ci -v $(pwd)/e2e:/etc/dyndnsd -p 8080:8080 -p 5353:5353 #{ci_image}"
+    sh 'sleep 1'
+    puts '----------------------------------------'
+    # `dig` needs `sudo apt-get install -y -q dnsutils`
+    sh <<~SCRIPT
+      curl -s -o /dev/null -w '%{http_code}' 'http://localhost:8080/' | grep -q '401'
+      curl -s 'http://foo:secret@localhost:8080/nic/update?hostname=foo.dyn.example.org&myip=1.2.3.4' | grep -q 'good'
+      curl -s 'http://foo:secret@localhost:8080/nic/update?hostname=foo.dyn.example.org&myip=1.2.3.4' | grep -q 'nochg'
+      dig +short AXFR 'dyn.example.org' @127.0.0.1 -p 5353 | grep -q '1.2.3.4'
+    SCRIPT
+    puts '----------------------------------------'
+    sh <<~SCRIPT
+      docker logs dyndnsd-ci
+      docker container rm -f -v dyndnsd-ci
+      rm e2e/db.json
+    SCRIPT
   end
 end
 
 task default: [:rubocop, :spec, 'bundle:audit', :solargraph]
 
 desc 'Run all tasks desired for CI'
-task ci: ['solargraph:init', :default, 'docker:lint', :build, 'docker:build']
+task ci: ['solargraph:init', :default, 'docker:lint', :build, 'docker:build', 'docker:e2e']