Define errors in a single place

lib/linux_admin.rb

@@ -2,6 +2,7 @@
 require 'active_support/core_ext'
 
 require 'linux_admin/common'
+require 'linux_admin/exceptions'
 require 'linux_admin/rhn'
 require 'linux_admin/rpm'
 require 'linux_admin/subscription_manager'

lib/linux_admin/common.rb

@@ -1,8 +1,6 @@
 require 'shellwords'
 
 class LinuxAdmin
-  class CommandError < RuntimeError; end
-
   module Common
     def cmd(cmd)
       Distro.local.class::COMMANDS[cmd]

lib/linux_admin/exceptions.rb

@@ -0,0 +1 @@
+  class CommandError < RuntimeError; end

lib/linux_admin/yum.rb

@@ -59,7 +59,7 @@ def self.update(*packages)
     end
 
     def self.version_available(*packages)
-      raise ArgumentError, "packages requires at least one package name" unless packages
+      raise ArgumentError, "packages requires at least one package name" if packages.blank?
 
       cmd    = "repoquery --qf=\"%{name} %{version}\""
       params = {nil => packages}

spec/common_spec.rb

@@ -70,11 +70,11 @@ class TestClass
       end
 
       it "command ok exit bad" do
-        expect { subject.run("false") }.to raise_error
+        expect { subject.run("false") }.to raise_error(CommandError)
       end
 
       it "command bad" do
-        expect { subject.run("XXXXX") }.to raise_error
+        expect { subject.run("XXXXX") }.to raise_error(Errno::ENOENT)
       end
 
       context "with :return_exitstatus => true" do
@@ -97,11 +97,11 @@ class TestClass
         end
 
         it "command ok exit bad" do
-          expect { subject.run("false", :return_output => true) }.to raise_error
+          expect { subject.run("false", :return_output => true) }.to raise_error(CommandError)
         end
 
         it "command bad" do
-          expect { subject.run("XXXXX", :return_output => true) }.to raise_error
+          expect { subject.run("XXXXX", :return_output => true) }.to raise_error(Errno::ENOENT)
         end
       end
     end

spec/yum_spec.rb

@@ -107,7 +107,7 @@
 
   context ".version_available" do
     it "no packages" do
-      expect { described_class.version_available }.to raise_error
+      expect { described_class.version_available }.to raise_error(ArgumentError)
     end
 
     it "with packages" do