diff --git a/tests/unit/test_plugin_registry.py b/tests/unit/test_plugin_registry.py
new file mode 100644
index 0000000..010589e
--- /dev/null
+++ b/tests/unit/test_plugin_registry.py
@@ -0,0 +1,139 @@
+import pytest
+
+from proxy_pool.plugins.protocols import CheckContext, CheckResult, DiscoveredProxy, Event
+from proxy_pool.plugins.registry import PluginConflictError, PluginNotFoundError, PluginRegistry, PluginValidationError
+
+
+class FakeParser:
+    name = "fake"
+
+    def supports(self, url: str) -> bool:
+        return "fake" in url
+
+    async def parse(self, raw, source_url, source_id, default_protocol):
+        return [DiscoveredProxy(ip="1.2.3.4", port=8080, protocol="http")]
+
+    def default_schedule(self):
+        return None
+
+
+class FakeChecker:
+    name = "fake_check"
+    stage = 1
+    priority = 0
+    timeout = 5.0
+
+    async def check(self, proxy_ip, proxy_port, proxy_protocol, context):
+        return CheckResult(passed=True, detail="ok")
+
+    def should_skip(self, proxy_protocol):
+        return False
+
+
+class FakeNotifier:
+    name = "fake_notify"
+    subscribes_to = ["test.*"]
+    notified_events: list[Event]
+
+    def __init__(self):
+        self.notified_events = []
+
+    async def notify(self, event):
+        self.notified_events.append(event)
+
+    async def health_check(self):
+        return True
+
+
+class TestParserRegistration:
+    def test_register_and_retrieve(self):
+        registry = PluginRegistry()
+        parser = FakeParser()
+        registry.register_parser(parser)
+
+        assert registry.get_parser("fake") is parser
+
+    def test_duplicate_name_raises_conflict(self):
+        registry = PluginRegistry()
+        registry.register_parser(FakeParser())
+
+        with pytest.raises(PluginConflictError):
+            registry.register_parser(FakeParser())
+
+    def test_get_missing_parser_raises(self):
+        registry = PluginRegistry()
+
+        with pytest.raises(PluginNotFoundError):
+            registry.get_parser("nonexistent")
+
+    def test_get_parser_for_url(self):
+        registry = PluginRegistry()
+        parser = FakeParser()
+        registry.register_parser(parser)
+
+        assert registry.get_parser_for_url("http://fake.com/list") is parser
+        assert registry.get_parser_for_url("http://other.com/list") is None
+
+    def test_invalid_plugin_raises_validation_error(self):
+        registry = PluginRegistry()
+
+        with pytest.raises(PluginValidationError):
+            registry.register_parser("not a plugin")
+
+
+class TestCheckerRegistration:
+    def test_checkers_sorted_by_stage_and_priority(self):
+        registry = PluginRegistry()
+
+        class Late(FakeChecker):
+            name = "late"
+            stage = 2
+            priority = 0
+
+        class Early(FakeChecker):
+            name = "early"
+            stage = 1
+            priority = 0
+
+        class EarlyLow(FakeChecker):
+            name = "early_low"
+            stage = 1
+            priority = 10
+
+        registry.register_checker(Late())
+        registry.register_checker(EarlyLow())
+        registry.register_checker(Early())
+
+        pipeline = registry.get_checker_pipeline()
+        names = [c.name for c in pipeline]
+        assert names == ["early", "early_low", "late"]
+
+
+class TestEventBus:
+    async def test_emit_notifies_matching_subscribers(self):
+        registry = PluginRegistry()
+        notifier = FakeNotifier()
+        registry.register_notifier(notifier)
+
+        event = Event(type="test.something", payload={"key": "value"})
+        await registry.emit(event)
+
+        # Give the fire-and-forget task a moment to run
+        import asyncio
+        await asyncio.sleep(0.05)
+
+        assert len(notifier.notified_events) == 1
+        assert notifier.notified_events[0].type == "test.something"
+
+    async def test_emit_skips_non_matching(self):
+        registry = PluginRegistry()
+        notifier = FakeNotifier()
+        notifier.subscribes_to = ["other.*"]
+        registry.register_notifier(notifier)
+
+        await registry.emit(Event(type="test.something", payload={}))
+
+        import asyncio
+        await asyncio.sleep(0.05)
+
+        assert len(notifier.notified_events) == 0
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