Fixed Inspec::Plugin::V2::Registry#detect_system_plugins

+ Falls back to checking for inspec-core if inspec not found.
+ Fails gracefully if neither are found.

Signed-off-by: Ryan Davis <zenspider@chef.io>

lib/inspec/plugin/v2/loader.rb

@@ -1,4 +1,5 @@
 require "inspec/log"
+require "inspec/version"
 require "inspec/plugin/v2/config_file"
 require "inspec/plugin/v2/filter"
 
@@ -274,9 +275,22 @@ module Inspec::Plugin::V2
       end
     end
 
+    def find_inspec_gemspec(name, ver)
+      Gem::Specification.find_by_name(name, ver)
+    rescue Gem::MissingSpecError
+      nil
+    end
+
     def detect_system_plugins
       # Find the gemspec for inspec
-      inspec_gemspec = Gem::Specification.find_by_name("inspec", "=#{Inspec::VERSION}")
+      inspec_gemspec =
+        find_inspec_gemspec("inspec",      "=#{Inspec::VERSION}") ||
+        find_inspec_gemspec("inspec-core", "=#{Inspec::VERSION}")
+
+      unless inspec_gemspec
+        Inspec::Log.warn "inspec gem not found, skipping detecting of system plugins"
+        return
+      end
 
       # Make a RequestSet that represents the dependencies of inspec
       inspec_deps_request_set = Gem::RequestSet.new(*inspec_gemspec.dependencies)

test/unit/plugin/v2/loader_test.rb

@@ -1,10 +1,14 @@
 # Unit tests for Inspec::PluginLoader and Registry
 
-require "minitest/autorun"
-require_relative "../../../../lib/inspec/plugin/v2"
+require "helper"
+require "inspec/plugin/v2"
 
 require "train" # Needed for Train plugin testing
 
+class Inspec::Plugin::V2::Loader
+  public :detect_system_plugins
+end
+
 class PluginLoaderTests < Minitest::Test
 
   @@orig_home = Dir.home
@@ -244,4 +248,82 @@ class PluginLoaderTests < Minitest::Test
     assert_includes(Train::Plugins.registry.keys, "test-fixture", "After requiring the gem, the Train Registry should know the plugin is loaded")
     assert(reg.loaded_plugin?(plugin_name), "After requiring, InSpec Registry should know the the plugin is loaded")
   end
+
+  REG_INST = Inspec::Plugin::V2::Registry.instance
+
+  def with_empty_registry
+    old_reg = REG_INST.registry.dup
+    REG_INST.registry.clear
+
+    yield
+  ensure
+    REG_INST.registry.replace old_reg
+  end
+
+  def with_logger
+    old_logger = Inspec::Log.logger
+    io = StringIO.new
+    Inspec::Log.logger = Logger.new(io)
+
+    yield
+
+    io.string
+  ensure
+    Inspec::Log.logger = old_logger
+  end
+
+  def using_bundler?
+    Gem::Specification.find_by_name("inspec")
+  rescue Gem::MissingSpecError
+    nil
+  end
+
+  def assert_detect_system_plugins(exp_keys, exp_err)
+    # rubocop:disable Style/HashSyntax
+    loader = Inspec::Plugin::V2::Loader.new(:omit_user_plugins => true,
+                                            :omit_bundles      => true,
+                                            :omit_core_plugins => true,
+                                            :omit_sys_plugins  => true)
+
+    assert_empty REG_INST.registry
+
+    yield loader
+
+    log_out = with_logger do
+      assert_silent do
+        loader.detect_system_plugins
+      end
+    end
+
+    assert_equal exp_keys, REG_INST.registry.keys.sort
+    assert_match exp_err, log_out
+  end
+
+  def test_detect_system_plugins
+    with_empty_registry do
+      exp = []
+      exp_err = "inspec gem not found, skipping detecting of system plugins\n"
+
+      assert_detect_system_plugins exp, exp_err do |loader|
+        def loader.find_inspec_gemspec(*)
+          nil
+        end
+      end
+    end
+  end
+
+  def test_detect_system_plugins_inspec
+    skip "not valid in this env" unless using_bundler?
+
+    with_empty_registry do
+      exp = %i{ train-aws train-habitat train-winrm }
+      exp_err = ""
+
+      assert_detect_system_plugins exp, exp_err do |loader|
+        def loader.find_inspec_gemspec(name, version)
+          super if name == "inspec"
+        end
+      end
+    end
+  end
 end