This tests the 'textPath/startOffset' with both negative and positive values, and compares it to the case where a 'tspan/dx' attribute is used with the same values.
Run the test. No interaction required. Make sure scripting is enabled.
You should see four paths with text following each path. The top two paths should show the text "Negative offset", and the bottom two paths should show the text "Positive offset".
The test has passed if: