Add spec for #exit! in #at_exit

* See #2047

Author: eregon

spec/ruby/shared/process/exit.rb

@@ -91,4 +91,18 @@
     out.should == ""
     $?.exitstatus.should == 21
   end
+
+  it "overrides the original exception and exit status when called from #at_exit" do
+    code = <<-RUBY
+    at_exit do
+      STDERR.puts 'in at_exit'
+      STDERR.puts "$! is \#{$!.class}:\#{$!.message}"
+      #{@object}.send(:exit!, 21)
+    end
+    raise 'original error'
+    RUBY
+    out = ruby_exe(code, args: '2>&1')
+    out.should == "in at_exit\n$! is RuntimeError:original error\n"
+    $?.exitstatus.should == 21
+  end
 end

spec/tags/core/kernel/exit_tags.txt

@@ -4,3 +4,5 @@ slow:Kernel#exit! exits when called from a fiber
 slow:Kernel.exit! exits with the given status
 slow:Kernel.exit! exits when called from a thread
 slow:Kernel.exit! exits when called from a fiber
+slow:Kernel#exit! overrides the original exception and exit status when called from #at_exit
+slow:Kernel.exit! overrides the original exception and exit status when called from #at_exit

spec/tags/core/process/exit_tags.txt

@@ -1,3 +1,4 @@
 slow:Process.exit! exits with the given status
 slow:Process.exit! exits when called from a thread
 slow:Process.exit! exits when called from a fiber
+slow:Process.exit! overrides the original exception and exit status when called from #at_exit