Initial Commit

packages/networking/drive/drive-mesh-protocol/tests/bitset-length-invariant.test.ts

@@ -0,0 +1,88 @@
+/**
+ * DMP-08 — Advertisement bitset length invariant.
+ *
+ * In `ChunkAdvertisePayload`, the bit-length of `presence` MUST equal
+ * `totalChunks`; padding bits in the final byte MUST be zero. The codec
+ * rejects mismatched bitset wires with either
+ * `DMP.BITSET_LENGTH_MISMATCH` or `DMP.BITSET_PADDING_NONZERO`.
+ */
+
+import { describe, expect, it } from "@suaveplan/testing/runner";
+import {
+    BITSET_MAGIC,
+    chunkIdsToRawBitset,
+    DMP_CODES,
+    DmpError,
+    decodeAdvertisePayload,
+    encodeAdvertisePayload,
+    encodeFramedBitset,
+} from "../src/index.js";
+
+const FILE_ID = "b".repeat(64);
+
+function makeAdvertise(presence: Uint8Array, totalChunks: number) {
+    return encodeAdvertisePayload({
+        fileId: FILE_ID,
+        presence,
+        totalChunks,
+        generation: 1,
+        timestamp: 0,
+    });
+}
+
+function makeFramedBitset(ids: number[], bitLength: number) {
+    return encodeFramedBitset(chunkIdsToRawBitset(ids, bitLength), bitLength);
+}
+
+describe("DMP-08 — bitset length invariant", () => {
+    it("advertisement with presence.length ≠ totalChunks rejected", {
+        timeout: 5000,
+    }, () => {
+        const presence = makeFramedBitset([0, 5], 16);
+        try {
+            makeAdvertise(presence, 32);
+            throw new Error("expected mismatch rejection");
+        } catch (err) {
+            expect(err).toBeInstanceOf(DmpError);
+            expect((err as DmpError).code).toBe(
+                DMP_CODES.BITSET_LENGTH_MISMATCH
+            );
+        }
+    });
+
+    it("valid advertisement (bitLength == totalChunks) round-trips", {
+        timeout: 5000,
+    }, () => {
+        const presence = makeFramedBitset([0, 5, 7], 8);
+        const wire = makeAdvertise(presence, 8);
+        const decoded = decodeAdvertisePayload(wire);
+        expect(decoded.totalChunks).toBe(8);
+        expect(decoded.presence).toEqual(presence);
+    });
+
+    it("non-zero padding bits rejected", { timeout: 5000 }, () => {
+        // Hand-build a framed bitset with bitLength=10 (so high bits 10..15
+        // must be zero) but flip bit 14 to violate padding zeroing.
+        const raw = new Uint8Array([0x01, 0xff]);
+        // Build the wire envelope by hand.
+        const wire = new Uint8Array(12 + raw.length);
+        wire.set(BITSET_MAGIC, 0);
+        const view = new DataView(
+            wire.buffer,
+            wire.byteOffset,
+            wire.byteLength
+        );
+        view.setUint32(4, 10, false);
+        view.setUint32(8, raw.length, false);
+        wire.set(raw, 12);
+        try {
+            makeAdvertise(wire, 10);
+            throw new Error("expected padding-nonzero rejection");
+        } catch (err) {
+            expect(err).toBeInstanceOf(DmpError);
+            expect((err as DmpError).code).toBe(
+                DMP_CODES.BITSET_PADDING_NONZERO
+            );
+        }
+    });
+});