Add integration test for docker transport

Gemfile

@@ -20,6 +20,7 @@ end
 group :integration do
   gem "berkshelf", ">= 4.3.5"
   gem "kitchen-dokken"
+  gem "kitchen-docker", ">= 2.10.0"
 end
 
 group :tools do

spec/kitchen/verifier/inspec_spec.rb

@@ -25,6 +25,7 @@
 require "kitchen/transport/exec"
 require "kitchen/transport/ssh"
 require "kitchen/transport/winrm"
+require "kitchen/transport/docker"
 
 describe Kitchen::Verifier::Inspec do
 
@@ -664,6 +665,39 @@
     end
   end
 
+  context "with a docker transport" do
+
+    let(:transport) do
+      Kitchen::Transport::Docker.new
+    end
+
+    let(:runner) do
+      instance_double("Inspec::Runner")
+    end
+
+    before do
+      allow(runner).to receive(:add_target)
+      allow(runner).to receive(:run).and_return 0
+    end
+
+    it "constructs a Inspec::Runner using transport config data and state" do
+      expect(Inspec::Runner).to receive(:new)
+        .with(
+          hash_including(
+            "backend" => "docker",
+            :backend_cache => true,
+            "color" => true,
+            :controls => nil,
+            "host" => nil,
+            "logger" => logger
+          )
+        )
+        .and_return(runner)
+
+      verifier.call({})
+    end
+  end
+
   context "with an unsupported transport" do
 
     it "#call raises a UserError" do