test: add capability matching tests for LSP clients

Author: observerw

tests/__init__.py

@@ -0,0 +1,30 @@
+from __future__ import annotations
+
+import pytest
+
+from lsp_client import LSPClient
+from lsp_client.clients import local_clients
+from lsp_client.utils.inspect import inspect_capabilities
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "client_cls",
+    local_clients,
+)
+async def test_capabilities_match(client_cls: type[LSPClient]):
+    # instantiate the client directly to get its default server
+    client = client_cls()
+    server = client.server
+
+    mismatches = []
+    async for result in inspect_capabilities(server, client_cls):
+        if result.client != result.server:
+            mismatches.append(
+                f"{result.capability}: client={result.client}, server={result.server}"
+            )
+
+    if mismatches:
+        pytest.fail(
+            f"Capability mismatch for {client_cls.__name__}:\n" + "\n".join(mismatches)
+        )