Add plugin dispatch test

Add test to verify that a plugin can run dispatch to handle subtasks of
external plugins.

tests/dotbot_plugin_dispatch.py

@@ -0,0 +1,17 @@
+"""Test that a plugin can call dispatcher for subtasks.
+
+The plugin calls dispatch with his data.
+"""
+
+import os.path
+
+import dotbot
+
+
+class Dispatch(dotbot.Plugin):
+    def can_handle(self, directive):
+        return directive == "dispatch"
+
+    def handle(self, directive, data):
+        dispatcher = dotbot.dispatcher.Dispatcher(self._context.base_directory())
+        return dispatcher.dispatch(data)

tests/test_dispatcher.py

@@ -0,0 +1,22 @@
+import os
+import shutil
+
+import pytest
+
+
+def test_plugin_dispatcher(capfd, home, dotfiles, run_dotbot):
+    """Verify that plugins can call dispatcher without explicitly specifying plugins."""
+
+    dotfiles.makedirs("plugins")
+    plugin_file = os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), "dotbot_plugin_dispatch.py"
+    )
+    shutil.copy(plugin_file, os.path.join(dotfiles.directory, "plugins", "dispatch.py"))
+    dotfiles.write_config(
+        [
+            {"dispatch": [{"create": ["~/a"]}]},
+        ]
+    )
+    run_dotbot("--plugin-dir", os.path.join(dotfiles.directory, "plugins"))
+
+    assert os.path.exists(os.path.join(home, "a"))