Move screenshot clearing to be before error raise (#90)

lib/capybara/screenshot/diff.rb

@@ -80,8 +80,11 @@ def self.included(klass)
 
         klass.teardown do
           if Screenshot.active? && @test_screenshots.present?
-            track_failures(@test_screenshots)
-            @test_screenshots.clear
+            begin
+              track_failures(@test_screenshots)
+            ensure
+              @test_screenshots.clear
+            end
           end
         end
       end

test/capybara/screenshot/diff_test.rb

@@ -127,6 +127,7 @@ def _test_sample_screenshot_error
 
           @test_screenshots = []
           @test_screenshots << ["my_test.rb:42", "sample_screenshot", mock]
+          mock.expect(:clear_screenshots, @test_screenshots)
         end
       end
 
@@ -174,6 +175,7 @@ def _test_sample_screenshot_error
           expected_message =
             "Screenshot does not match for 'sample_screenshot' expected error message for non minitest"
           assert_raises(RuntimeError, expected_message) { test_case.teardown }
+          assert(test_case.instance_variable_get(:@test_screenshots).empty?)
         end
       end
     end