Source code for envisage.tests.test_provider_extension_registry

# (C) Copyright 2007-2023 Enthought, Inc., Austin, TX
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD
# license included in LICENSE.txt and may be redistributed only under
# the conditions described in the aforementioned license. The license
# is also available online at http://www.enthought.com/licenses/BSD.txt
#
# Thanks for using Enthought open source!
""" Tests for the provider extension registry. """

# Standard library imports.
import unittest

from traits.api import Int, List

# Enthought library imports.
from envisage.api import (
    ExtensionPoint,
    ExtensionProvider,
    ProviderExtensionRegistry,
)

# Local imports.
from envisage.tests.test_extension_registry_mixin import (
    ExtensionRegistryTestMixin,
)


class ProviderExtensionRegistryTestCase(
    ExtensionRegistryTestMixin, unittest.TestCase
):
    """Tests for the provider extension registry."""

    def setUp(self):
        """Prepares the test fixture before each test method is called."""

        self.registry = ProviderExtensionRegistry()

    def test_providers(self):
        """providers"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            def get_extension_points(self):
                """Return the extension points offered by the provider."""

                return [ExtensionPoint(List, "x")]

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    extensions = [42, 43]

                else:
                    extensions = []

                return extensions

        class ProviderB(ExtensionProvider):
            """An extension provider."""

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    extensions = [44, 45, 46]

                else:
                    extensions = []

                return extensions

        class ProviderC(ExtensionProvider):
            """An empty provider!"""

        # Add the providers to the registry.
        registry.add_provider(ProviderA())
        registry.add_provider(ProviderB())
        registry.add_provider(ProviderC())

        # The provider's extensions should now be in the registry.
        extensions = registry.get_extensions("x")
        self.assertEqual(5, len(extensions))
        self.assertEqual(list(range(42, 47)), extensions)

        # Make sure there's one and only one extension point.
        extension_points = registry.get_extension_points()
        self.assertEqual(1, len(extension_points))
        self.assertEqual("x", extension_points[0].id)

    def test_provider_extensions_changed(self):
        """provider extensions changed"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            x = List(Int)

            def get_extension_points(self):
                """Return the extension points offered by the provider."""

                return [ExtensionPoint(List, "my.ep")]

            def get_extensions(self, extension_point_id):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point_id == "my.ep":
                    return self.x

                else:
                    extensions = []

                return extensions

            def _x_changed(self, old, new):
                """Static trait change handler."""

                self._fire_extension_point_changed(
                    "my.ep", new, old, slice(0, len(old))
                )

            def _x_items_changed(self, event):
                """Static trait change handler."""

                self._fire_extension_point_changed(
                    "my.ep", event.added, event.removed, event.index
                )

        class ProviderB(ExtensionProvider):
            """An extension provider."""

            x = List(Int)

            def get_extensions(self, extension_point_id):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point_id == "my.ep":
                    return self.x

                else:
                    extensions = []

                return extensions

            def _x_changed(self, old, new):
                """Static trait change handler."""

                self._fire_extension_point_changed(
                    "my.ep", new, old, slice(0, len(old))
                )

            def _x_items_changed(self, event):
                """Static trait change handler."""

                self._fire_extension_point_changed(
                    "my.ep", event.added, event.removed, event.index
                )

        # Add the providers to the registry.
        a = ProviderA(x=[42])
        b = ProviderB(x=[99, 100])
        registry.add_provider(a)
        registry.add_provider(b)

        # The provider's extensions should now be in the registry.
        extensions = registry.get_extensions("my.ep")
        self.assertEqual(3, len(extensions))
        self.assertEqual([42, 99, 100], extensions)

        # Add an extension listener to the registry.
        def listener(registry, event):
            """A useful trait change handler for testing!"""

            listener.registry = registry
            listener.extension_point = event.extension_point_id
            listener.added = event.added
            listener.removed = event.removed
            listener.index = event.index

        registry.add_extension_point_listener(listener, "my.ep")

        # Add a new extension via the provider.
        a.x.append(43)

        # Make sure the listener got called.
        self.assertEqual("my.ep", listener.extension_point)
        self.assertEqual([43], listener.added)
        self.assertEqual([], listener.removed)
        self.assertEqual(1, listener.index)

        # Now we should get the new extension.
        extensions = registry.get_extensions("my.ep")
        self.assertEqual(4, len(extensions))
        self.assertEqual([42, 43, 99, 100], extensions)

        # Insert a new extension via the other provider.
        b.x.insert(0, 98)

        # Make sure the listener got called.
        self.assertEqual("my.ep", listener.extension_point)
        self.assertEqual([98], listener.added)
        self.assertEqual([], listener.removed)
        self.assertEqual(2, listener.index)

        # Now we should get the new extension.
        extensions = registry.get_extensions("my.ep")
        self.assertEqual(5, len(extensions))
        self.assertEqual([42, 43, 98, 99, 100], extensions)

        # Completely change a provider's extensions.
        b.x = [1, 2]

        # Make sure the listener got called.
        self.assertEqual("my.ep", listener.extension_point)
        self.assertEqual([1, 2], listener.added)
        self.assertEqual([98, 99, 100], listener.removed)
        self.assertEqual(2, listener.index.start)
        self.assertEqual(5, listener.index.stop)

        # Now we should get the new extension.
        extensions = registry.get_extensions("my.ep")
        self.assertEqual(4, len(extensions))
        self.assertEqual([42, 43, 1, 2], extensions)

    def test_add_provider(self):
        """add provider"""

        registry = self.registry

        # A provider.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            def get_extension_points(self):
                """Return the extension points offered by the provider."""

                return [ExtensionPoint(List, "x")]

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    return [42]

                else:
                    extensions = []

                return extensions

            def _x_items_changed(self, event):
                """Static trait change handler."""

                self._fire_extension_point_changed(
                    "x", event.added, event.removed, event.index
                )

        # Add the provider to the registry.
        registry.add_provider(ProviderA())

        # The provider's extensions should now be in the registry.
        extensions = registry.get_extensions("x")
        self.assertEqual(1, len(extensions))
        self.assertTrue(42 in extensions)

        # Add an extension listener to the registry.
        def listener(registry, event):
            """A useful trait change handler for testing!"""

            listener.registry = registry
            listener.extension_point = event.extension_point_id
            listener.added = event.added
            listener.removed = event.removed
            listener.index = event.index

        registry.add_extension_point_listener(listener, "x")

        # Add a new provider.
        class ProviderB(ExtensionProvider):
            """An extension provider."""

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    extensions = [43, 44]

                else:
                    extensions = []

                return extensions

        registry.add_provider(ProviderB())

        # Make sure the listener got called.
        self.assertEqual("x", listener.extension_point)
        self.assertEqual([43, 44], listener.added)
        self.assertEqual([], listener.removed)

        # Now we should get the new extensions.
        extensions = registry.get_extensions("x")
        self.assertEqual(3, len(extensions))
        self.assertTrue(42 in extensions)
        self.assertTrue(43 in extensions)
        self.assertTrue(44 in extensions)

    def test_get_providers(self):
        """get providers"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

        class ProviderB(ExtensionProvider):
            """An extension provider."""

        a = ProviderA()
        b = ProviderB()

        # Add the provider to the registry.
        registry.add_provider(a)
        registry.add_provider(b)

        # Make sure we can get them.
        self.assertEqual([a, b], registry.get_providers())

    def test_remove_provider(self):
        """remove provider"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            def get_extension_points(self):
                """Return the extension points offered by the provider."""

                return [ExtensionPoint(List, "x"), ExtensionPoint(List, "y")]

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    return [42]

                else:
                    extensions = []

                return extensions

            def _x_items_changed(self, event):
                """Static trait change handler."""

                self._fire_extension_point_changed(
                    "x", event.added, event.removed, event.index
                )

        class ProviderB(ExtensionProvider):
            """An extension provider."""

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    extensions = [43, 44]

                else:
                    extensions = []

                return extensions

        # Add the providers to the registry.
        a = ProviderA()
        b = ProviderB()
        registry.add_provider(a)
        registry.add_provider(b)

        # The provider's extensions should now be in the registry.
        extensions = registry.get_extensions("x")
        self.assertEqual(3, len(extensions))
        self.assertTrue(42 in extensions)
        self.assertTrue(43 in extensions)
        self.assertTrue(44 in extensions)

        # Add an extension listener to the registry.
        def listener(registry, event):
            """A useful trait change handler for testing!"""

            listener.registry = registry
            listener.extension_point = event.extension_point_id
            listener.added = event.added
            listener.removed = event.removed

        registry.add_extension_point_listener(listener, "x")

        # Remove one of the providers.
        registry.remove_provider(b)

        # Make sure the listener got called.
        self.assertEqual("x", listener.extension_point)
        self.assertEqual([], listener.added)
        self.assertEqual([43, 44], listener.removed)

        # Make sure we don't get the removed extensions.
        extensions = registry.get_extensions("x")
        self.assertEqual(1, len(extensions))
        self.assertTrue(42 in extensions)

        # Now remove the provider that declared the extension point.
        registry.remove_provider(a)

        # Make sure the extension point is gone.
        self.assertEqual(None, registry.get_extension_point("x"))

        # Make sure we don't get the removed extensions.
        extensions = registry.get_extensions("x")
        self.assertEqual(0, len(extensions))

        # Make sure the listener got called.
        self.assertEqual("x", listener.extension_point)
        self.assertEqual([], listener.added)
        self.assertEqual([42], listener.removed)

    def test_remove_provider_with_no_contributions(self):
        """remove provider with no contributions"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            def get_extension_points(self):
                """Return the extension points offered by the provider."""

                return [ExtensionPoint(List, "x"), ExtensionPoint(List, "y")]

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                return []

        # Add the provider to the registry.
        a = ProviderA()
        registry.add_provider(a)

        # The provider's extensions should now be in the registry.
        extensions = registry.get_extensions("x")
        self.assertEqual(0, len(extensions))

        # Add an extension listener to the registry.
        def listener(registry, event):
            """A useful trait change handler for testing!"""

            listener.registry = registry
            listener.extension_point = event.extension_point_id
            listener.added = event.added
            listener.removed = event.removed

        registry.add_extension_point_listener(listener, "x")

        # Remove the provider that declared the extension point.
        registry.remove_provider(a)

        # Make sure the extension point is gone.
        self.assertEqual(None, registry.get_extension_point("x"))

        # Make sure we don't get the removed extensions.
        extensions = registry.get_extensions("x")
        self.assertEqual(0, len(extensions))

        # Make sure the listener did not get called  (since the provider did
        # not make any contributions anyway!).
        self.assertEqual(None, getattr(listener, "registry", None))

    def test_remove_non_existent_provider(self):
        """remove provider"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            pass

        a = ProviderA()

        # Remove one of the providers.
        with self.assertRaises(ValueError):
            registry.remove_provider(a)

    def test_set_extensions(self):
        """set extensions"""

        registry = self.registry

        # Add an extension *point*.
        registry.add_extension_point(self.create_extension_point("my.ep"))

        # Set some extensions.
        with self.assertRaises(TypeError):
            registry.set_extensions("my.ep", [1, 2, 3])

    def test_remove_non_empty_extension_point(self):
        """remove non-empty extension point"""

        registry = self.registry

        # Some providers.
        class ProviderA(ExtensionProvider):
            """An extension provider."""

            def get_extension_points(self):
                """
                Return the extension points offered by the provider.
                """

                return [ExtensionPoint(List, "x")]

            def get_extensions(self, extension_point):
                """
                Return the provider's contributions to an extension point.
                """

                if extension_point == "x":
                    extensions = [42, 43]

                else:
                    extensions = []

                return extensions

        # Add the provider to the registry.
        registry.add_provider(ProviderA())

        # The provider's extensions should now be in the registry.
        extensions = registry.get_extensions("x")
        self.assertEqual(2, len(extensions))
        self.assertEqual(list(range(42, 44)), extensions)

        # Make sure there's one and only one extension point.
        extension_points = registry.get_extension_points()
        self.assertEqual(1, len(extension_points))
        self.assertEqual("x", extension_points[0].id)

        # Remove the extension point.
        registry.remove_extension_point("x")

        # Make sure there are no extension points.
        extension_points = registry.get_extension_points()
        self.assertEqual(0, len(extension_points))

        # And that the extensions are gone too.
        self.assertEqual([], registry.get_extensions("x"))