napari-plugin-devtools

A repo with tools and services for napari plugin developers

Installation

This tool can be installed via pip: pip install napari-plugin-devtools, you can also add it to your requirements.txt to be installed with other dependencies automatically.

Validation tool

The validation tools provides automated tests for plugin developers, these checks verify that the plugin is available for users of napari to install, and would register entry points with napari.

There are two parts to the validation tool. One part is a command line interface and the other is a pytest fixture.

Command Line Interface (CLI) Usage

The CLI can be used by continuous integration (CI) pipelines to perform a quick verification of a plugins setup without any specific input required. It serves as a quick "sanity check". (It is also accessible from python in validation.py)

The tool can be run as npd <cmd>. There are 2 commands currently:

npd --validate-packages should be used after packages are built for pypi releases, (example: this repo is built by pep517 standard pip install pep517 && python -m pep517.build .). The validator checks that all packages built under dist are correctly tagged with classifier "Framework :: napari". This is recommended for most plugins unless you do not want your plugin to appear in the napari built-in plugin installation tool.

npd --validate-readers|--validate-writers|--validate-functions|--validate-widgets, verifies that after the plugin is installed to current python environment, typically done through pip install -e ., there is at least one hook under corresponding category registered by the plugin, and there are no conflicts in name or registration error, it also output all registered function signatures in a json format that can be used for further inspection, for example:

    [{
        "plugin name": "napari-demo",
        "function name": "image arithmetic",
        "args": ["layerA", "operation", "layerB"],
        "annotations": {
            "return": "napari.types.ImageData",
            "layerA": "napari.types.ImageData",
            "operation": "<enum 'Operation'>",
            "layerB": "napari.types.ImageData"
        },
        "defaults": null
    }]

Multiple cmds in one execution is supported, for example: npd --validate-readers --validate-functions --validate-packages

Pytest fixture usage

devtools provides a pytest fixture: napari_plugin_tester in plugin_tester.py, it extends a plugin manager used by napari and have additional assertion modes ready:

def test_pm(napari_plugin_tester):
    napari_plugin_tester.assert_plugin_name_registered("test-plugin")
    napari_plugin_tester.assert_module_registered(_test)
    napari_plugin_tester.assert_implementations_registered(
        "test-plugin", "napari_get_reader"
    )

where you can check more specifically on a module or function being registered under napari annotations, see hook specifications to find what other annotations are avaiable in addition to napari_get_reader