Intercept width warning message for plugin list

Signed-off-by: Clinton Wolfe <clintoncwolfe@gmail.com>

test/artifact/inspec_plugin_test.rb

@@ -1,7 +1,13 @@
 require_relative "artifact_helper"
 
 class TestInspecPlugin < ArtifactTest
-  def test_plugin_lsit
-    assert_artifact("plugin list")
+  def test_plugin_list
+    # This one is custom because it emits a special warning to stderr
+    inspec_command = "plugin list"
+    stdout, stderr, status = run_cmd "inspec #{inspec_command} #{TEST_CLI_OPTS}"
+
+    assert_empty stderr.sub(/#< CLIXML\n/, "").sub(/The table size exceeds the currently set width\.Defaulting to vertical orientation\.\n/, "")
+    assert stdout
+    assert status
   end
 end