Defaults: protect against ArgumentError when no HOME

lib/chef-api/defaults.rb

@@ -1,4 +1,5 @@
 require 'chef-api/version'
+require 'pathname'
 require 'json'
 
 module ChefAPI
@@ -24,8 +25,32 @@ def options
       #
       # @return [Hash]
       def config
-        path = File.expand_path(ENV['CHEF_API_CONFIG'] || '~/.chef-api')
-        @config ||= File.exist?(path) ? JSON.parse(File.read(path)) : {}
+        path = config_path
+        @config ||= path.exist? ? JSON.parse(path.read) : {}
+      end
+
+      #
+      # Pathname to configuration file, or a blank Pathname.
+      #
+      # @return [Pathname] an expanded Pathname or a non-existent Pathname
+      def config_path
+        if result = chef_api_config_path
+          Pathname(result).expand_path
+        else
+          Pathname('')
+        end
+      end
+
+      #
+      # String representation of path to configuration file
+      #
+      # @return [String, nil] Path to config file, or nil
+      def chef_api_config_path
+        ENV['CHEF_API_CONFIG'] || if ENV.key?('HOME')
+                                    '~/.chef-api'
+                                  else
+                                    nil
+                                  end
       end
 
       #

spec/unit/defaults_spec.rb

@@ -2,6 +2,10 @@
 
 module ChefAPI
   describe Defaults do
+    before(:each) do
+      subject.instance_variable_set(:@config, nil)
+    end
+
     context 'without a config file' do
       before(:each) do
         allow(subject).to receive(:config).and_return(Hash.new)
@@ -16,15 +20,32 @@ module ChefAPI
       end
     end
 
+    context 'without a config file and no ENV vars to find it' do
+      around do |example|
+        old_conf = ENV.delete('CHEF_API_CONFIG')
+        old_home = ENV.delete('HOME')
+        example.run
+        ENV['CHEF_API_CONFIG'] = old_conf
+        ENV['HOME'] = old_home
+      end
+
+      it 'returns the default without errors' do
+        expect { subject.config }.not_to raise_error
+      end
+
+      it 'returns the default which is the empty hash' do
+        expect(subject.config).to eq({})
+      end
+    end
+
     context 'with a config file' do
       before(:each) do
-        subject.instance_variable_set(:@config, nil)
-        allow(File).to receive(:exist?).with(anything()).and_return(true)
-        allow(File).to receive(:read).and_return("{\n"\
+        config_content = "{\n"\
             "\"CHEF_API_ENDPOINT\": \"test_endpoint\",\n" \
             "\"CHEF_API_USER_AGENT\": \"test_user_agent\"\n" \
             "}"
-        )
+        path = instance_double(Pathname, read: config_content, exist?: true)
+        allow(subject).to receive(:config_path).and_return(path)
       end
 
       it 'returns the overridden value for endpoint' do