Since the plugin implementations rely on the base plugin interfaces for
file handling, this affected only the tests. Also took this as an
opportunity to use the new TestSuite::Compare::StringHasPrefix etc. in
various places.
It doesn't make the test any simpler, easier to understand or less
error prone, on the contrary. And it would stop testing the intended
code path once file callbacks are implemented inside the importer.
These checks covered the case when the magnum-plugins repository wasn't
installed, but didn't cover the case when it was installed but the
plugins were built against an outdated interface, had ABI issues, or
didn't load at all for various other reasons.
And prefere to use it onver OpenEXR in most AnyImage{Converter,Importer}
tests, unless the test really needs something that only OpenEXR has
(such as the verbose output for threads or configuration that needs to
be set on both export and import to make the import succeed).
Minor but very important convenience feature, especially useful when
dealing with command-line apps. This now works:
magnum-imageconverter a.png a.jpg -c jpegQuality=0.75
The AnyImageConverter gets the jpegQuality option and then
automatically propagates it to the concrete plugin (which is either
JpegImageConverter or StbImageConverter), possibly warning in case the
target plugin doesn't recognize given option (i.e., doesn't list it in
its default configuration). Previously the user had to always specify a
concrete converter implementation using -C, which was rather annoying
and nonintuitive.
And also test various potential false positives, which shouldn't be
detected as given format.
*Damn*, I need some utility class for printing this, this is
unsustainable.
It'll get used outside of the root namespace and since the callbacks tend
to be quite complex, it would be silly to require users to implement one
callback for Trade, one for Text and one for Audio, for example.
The original implementation had a few problems:
- If a file callback was set, openFile() was unconditionally calling
right into doOpenData(), making it impossible for the importer to
know the original path for correctly supplying paths to additional
files. Now, if the importer supports Feature::FileCallback,
doOpenFile() is always called. It's also possible for the importer to
save the path and then just delegate to the base doOpenFile()
implementation -- it will handle the file callbacks correctly too.
- If the importer supported neither FileCallback nor OpenData and
callbacks were set, the original doOpenFile() implementation was
called without any warning or anything, doing silently a bad thing.
Now in this case setFileCallbacks() asserts -- programmer has to
check for feature support first.
- It was not possible for the file callback to indicate file opening
failure -- in general, empty files are valid, so a nullptr ArrayView
is also a valid file. Now the callback return an Optional instead.
The current testing workflow had quite a few major flaws and it was no
longer possible after the move of Any* plugins to core. Among the flaws
is:
* Every plugin was basically built twice, once as the real plugin and
once as a static testing library. Most of the build shared common
object files, but nevertheless it inflated build times and made the
buildsystem extremely complex.
* Because the actual plugin binary was never actually loaded during the
test, it couldn't spot problems like:
- undefined references
- errors in metadata files
- mismatched plugin interface/version, missing entry points
- broken static plugin import files
* Tests that made use of independent plugins (such as TgaImageConverter
test using TgaImporter to verify the output) had a hardcoded
dependency on such plugins, making a minimal setup very hard.
* Dynamic loading of plugins from the Any* proxies was always directed
to the install location on the filesystem with no possibility to
load these directly from the build tree. That caused random ABI
mismatch crashes, or, on the other hand, if no plugins were
installed, particular portions of the codebase weren't tested at all.
Now the workflow is the following:
* Every plugin is built exactly once, either as dynamic or as static.
* The test always loads it via the plugin manager. If it's dynamic,
it's loaded straight from the build directory; if it's static, it
gets linked to the test executable directly.
* Plugins used indirectly are always served from the build directory
(if enabled) to ensure reproducibility and independence on what's
installed on the filesystem. Missing presence of these plugins causes
particular tests to be simply skipped.
* Plugins that have extensive tests for internal functionality that's
not exposed through the plugin interface are still built in two
parts, but the internal tests are simply consuming the OBJECT files
directly instead of linking to a static library.
Vladimír Vondruš