Explain why the export tests are enabled for formats that are not
expected to work well with certain document classes, modules, or
packages. The reason is that if a .lyx file goes from compiling
successfully for one format (even if that format is not officially
supported for the combination of features used), if that document
suddenly fails to compile, there is a significant chance that a bug
was introduced in LyX. In other words, there is a high signal/noise
ratio. If it is determined that a test is failing because an
expected incompatibility is exposed, then the test can be inverted.
The export tests, check_load tests, and URL tests are now documented
in the Development.lyx file. The export tests are described in
detail, such as how to run them and how to interpret the results.
Since Kornel's commit at e2d41970, it is now possible to update the
tex2lyx tests with CMake. Note that this is a case where a make
target in the build directory can affect the source directory, which
might not be advisable.
Writing these policies down makes it easier for newcommers to
understand guidelines and the intuition behind them.
The two policies this commit adds were responses by Georg and Richard
to two threads on the mailing list. The policies are titled
"When to set a fixed milestone" and
"Can we add rc entries in stable branch?".
These should be used if any new style needs to be introduced in the stable
2.1 series: If the ForceLocal flag of the style is set, it will always be
written to the document header, so that even older 2.1 versions can read
and correctly output the document.
