Load configuration when running chef update

Similar to `chef install`, `chef update` does not have any direct
configurables, but may rely on configuration being loaded in order to
configure SSL to correctly verify connections to a private supermarket.

lib/chef-dk/command/update.rb

@@ -19,12 +19,15 @@
 require 'chef-dk/ui'
 require 'chef-dk/policyfile_services/install'
 require 'chef-dk/policyfile_services/update_attributes'
+require 'chef-dk/configurable'
 
 module ChefDK
   module Command
 
     class Update < Base
 
+      include Configurable
+
       banner(<<-BANNER)
 Usage: chef update [ POLICY_FILE ] [options]
 
@@ -45,6 +48,11 @@ class Update < Base
 
 BANNER
 
+      option :config_file,
+        short:       "-c CONFIG_FILE",
+        long:        "--config CONFIG_FILE",
+        description: "Path to configuration file"
+
       option :debug,
         short:        "-D",
         long:         "--debug",
@@ -74,6 +82,13 @@ def initialize(*args)
 
       def run(params = [])
         return 1 unless apply_params!(params)
+
+        # Force config file to be loaded. We don't use the configuration
+        # directly, but the user may have SSL configuration options that they
+        # need to talk to a private supermarket (e.g., trusted_certs or
+        # ssl_verify_mode)
+        chef_config
+
         if update_attributes?
           attributes_updater.run
         else
@@ -98,6 +113,10 @@ def debug?
         !!config[:debug]
       end
 
+      def config_path
+        config[:config_file]
+      end
+
       def update_attributes?
         !!config[:update_attributes]
       end

spec/unit/command/update_spec.rb

@@ -39,6 +39,10 @@
     expect(command.debug?).to be(false)
   end
 
+  it "doesn't set a config path by default" do
+    expect(command.config_path).to be_nil
+  end
+
   context "when debug mode is set" do
 
     let(:params) { [ "-D" ] }
@@ -48,6 +52,26 @@
     end
   end
 
+  context "when an explicit config file path is given" do
+
+    let(:params) { %w[ -c ~/.chef/alternate_config.rb ] }
+
+    let(:chef_config_loader) { instance_double("Chef::WorkstationConfigLoader") }
+
+    it "sets the config file path to the given value" do
+      expect(command.config_path).to eq("~/.chef/alternate_config.rb")
+    end
+
+    it "loads the config from the given path" do
+      expect(Chef::WorkstationConfigLoader).to receive(:new).
+        with("~/.chef/alternate_config.rb").
+        and_return(chef_config_loader)
+      expect(chef_config_loader).to receive(:load)
+      expect(command.chef_config).to eq(Chef::Config)
+    end
+
+  end
+
   context "when attributes update mode is set" do
 
     let(:params) { ["-a"] }