Moved test to relevant file, added integration test

spec/bugsnag_spec.rb

@@ -16,4 +16,56 @@
       expect(Bugsnag.configuration.logger).to have_received(:warn)
     end
   end
+
+  describe "add_exit_handler" do
+
+    before do
+      Bugsnag.reset_exit_handler_added
+      module Kernel
+        alias_method :old_at_exit, :at_exit
+        def at_exit
+          begin
+            raise BugsnagTestException.new("Oh no")
+          rescue
+            yield
+          end
+        end
+      end
+    end
+
+    it "automatically adds an exit handler" do
+      expect(Bugsnag).to receive(:register_at_exit)
+      Bugsnag.configure do |conf|
+        conf.api_key = "TEST KEY"
+      end
+    end
+
+    it "calls at_exit when register_at_exit is called" do
+      expect(Bugsnag).to receive(:at_exit)
+      Bugsnag.register_at_exit
+    end
+
+    it "doesn't call at_exit on subsequent calls" do
+      expect(Bugsnag).to receive(:at_exit).once
+      Bugsnag.register_at_exit
+      Bugsnag.register_at_exit
+    end
+
+    it "sends an exception when at_exit is called" do
+      report_mock = double('report')
+      expect(report_mock).to receive(:severity=).with('error')
+      expect(report_mock).to receive(:severity_reason=).with({
+        :type => Bugsnag::Report::UNHANDLED_EXCEPTION
+      })
+      expect(Bugsnag).to receive(:notify).with(kind_of(BugsnagTestException), true).and_yield(report_mock)
+      Bugsnag.register_at_exit
+    end
+
+    after do
+      module Kernel
+        alias_method :at_exit, :old_at_exit
+      end
+    end
+
+  end
 end

spec/configuration_spec.rb

@@ -33,30 +33,4 @@
       expect(subject.ignore_classes).to eq(Set.new([SystemExit, Interrupt]))
   end
 
-  describe "add_exit_handler" do
-
-    before do
-      Bugsnag.reset_exit_handler_added
-    end
-
-    it "automatically adds an exit handler" do
-      expect(Bugsnag).to receive(:register_at_exit)
-      Bugsnag.configure do |conf|
-        conf.api_key = "TEST KEY"
-      end
-    end
-
-    it "calls at_exit when register_at_exit is called" do
-      expect(Bugsnag).to receive(:at_exit)
-      Bugsnag.register_at_exit
-    end
-
-    it "doesn't call at_exit on subsequent calls" do
-      expect(Bugsnag).to receive(:at_exit).once
-      Bugsnag.register_at_exit
-      Bugsnag.register_at_exit
-    end
-
-  end
-
 end