test: read the WebRTC transport's source as a set of files

Source-reading tests take their text from node_source (node) and node_tree
(hub): webrtc_server.py plus anything under transport/webrtc/, so a check
for something's absence keeps reading the code it guards if that code moves.
test_node_source_scope holds the boundary.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/packages/meshbay-node/tests/node_source.py b/packages/meshbay-node/tests/node_source.py
new file mode 100644
index 0000000..df63773
--- /dev/null
+++ b/packages/meshbay-node/tests/node_source.py
@@ -0,0 +1,52 @@
+"""
+The node's source text, for the tests that have to read it.
+
+A test that reads source to prove something is *absent* — no bare
+`ensure_future`, no exception text sent to a peer, no GEK unwrapped over MNP —
+goes on passing when the code it guards moves to another file: it simply stops
+looking at that code. So every such test takes its text from here, and the
+file sets below are derived from the tree rather than listed, so that a module
+added later is read without anybody having to remember it.
+"""
+
+import inspect
+import textwrap
+from pathlib import Path
+
+SRC = Path(__file__).resolve().parents[1] / "src" / "meshbay_node"
+TRANSPORT = SRC / "transport"
+
+# The WebRTC transport is `webrtc_server.py` and whatever has been split out of
+# it into `transport/webrtc/`. The other modules beside them are not part of it
+# and are not held to its rules by these tests: QUIC is a transport of its own
+# and not at parity (docs/MESHBAY_DESIGN.md §15.3), and `wire.py`, `tls_cert.py`
+# and the ICE helpers serve both or neither.
+WEBRTC_PACKAGE = TRANSPORT / "webrtc"
+
+
+def webrtc_files() -> list[Path]:
+    """Every module of the WebRTC transport, however it is split up."""
+    files = [TRANSPORT / "webrtc_server.py"]
+    if WEBRTC_PACKAGE.is_dir():
+        files += sorted(p for p in WEBRTC_PACKAGE.rglob("*.py")
+                        if "__pycache__" not in p.parts)
+    return files
+
+
+def webrtc_source() -> str:
+    return "\n".join(p.read_text(encoding="utf-8") for p in webrtc_files())
+
+
+def session_source() -> str:
+    """The body of WebRTCPeerSession, including every class it is built from."""
+    from meshbay_node.transport.webrtc_server import WebRTCPeerSession
+
+    return "\n".join(inspect.getsource(k) for k in WebRTCPeerSession.__mro__
+                     if k.__module__.startswith("meshbay_node."))
+
+
+def session_method(name: str) -> str:
+    """One method of WebRTCPeerSession, wherever it is defined."""
+    from meshbay_node.transport.webrtc_server import WebRTCPeerSession
+
+    return textwrap.dedent(inspect.getsource(getattr(WebRTCPeerSession, name)))