Test Your Styles with the New Style Tester

Styles (configurations) for osm2pgsql are written in the Lua programming language. And they are becoming more complex. Users have been asking for a long time for some way of testing those styles to help with writing and debugging the Lua code. We now have a solution for you.

We have had tests for osm2pgsql, the software, for a long time. This includes tests that run osm2pgsql with certain inputs and parameters and check that osm2pgsql produces the correct output, including checks that make sure the correct information ends up in the correct database tables. These kinds of tests are really similar to what users need, but the tests were deeply integrated with the rest of the osm2pgsql testing system, they were hard to use, and they were not documented.

We have polished that testing framework, documented it and made it work on its own and are now making it available for osm2pgsql users. So you can now use the same testing engine used for internal testing to test your style sheets. The test code builds upon the Python BDD behave testing framework, and adds all sorts of useful features to the tests. OSM test data can be integrated in various ways, inline in the test file or as external data. And we have added various handy features for testing database content.

Style testing will be available in the next version of osm2pgsql, but you can already try it out. You only need to download a single file from the current master and can use that with any reasonably modern version of osm2pgsql. Find the full documentation in the manual.

We’d love it if you tried the new style tester and tell us what you think. We are sure there will be some teething problems you can help us find and fix before the next release.