Test that sandbox complains correctly

Test that sandbox does not complain about bogus .pyc errors and does
complain about other failures.

Closes #684.

Library/Homebrew/test/test_sandbox.rb

@@ -25,4 +25,30 @@ class SandboxTest < Homebrew::TestCase
     end
     refute_predicate @file, :exist?
   end
+
+  def test_complains_on_failure
+    Utils.expects(:popen_read => "foo")
+    ARGV.stubs(:verbose? => true)
+    out, _err = capture_io do
+      assert_raises(ErrorDuringExecution) { @sandbox.exec "false" }
+    end
+    assert_match "foo", out
+  end
+
+  def test_ignores_bogus_python_error
+    with_bogus_error = <<-EOS.undent
+      foo
+      Mar 17 02:55:06 sandboxd[342]: Python(49765) deny file-write-unlink /System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/errors.pyc
+      bar
+    EOS
+    Utils.expects(:popen_read => with_bogus_error)
+    ARGV.stubs(:verbose? => true)
+    out, _err = capture_io do
+      assert_raises(ErrorDuringExecution) { @sandbox.exec "false" }
+    end
+    refute_predicate out, :empty?
+    assert_match "foo", out
+    assert_match "bar", out
+    refute_match "Python", out
+  end
 end