feat: enhance toAccountSnapshot function with improved market ID and symbol matching logic, and add corresponding unit tests

tests/lighter/mappers.test.ts

@@ -0,0 +1,56 @@
+import { describe, expect, it } from "vitest";
+import { toAccountSnapshot } from "../../src/exchanges/lighter/mappers";
+import type { LighterAccountDetails, LighterPosition } from "../../src/exchanges/lighter/types";
+
+const baseDetails: LighterAccountDetails = {
+  account_index: 1,
+  collateral: "1000",
+};
+
+function createPosition(overrides: Partial<LighterPosition> = {}): LighterPosition {
+  return {
+    market_id: 101,
+    symbol: "BTC/USDC:USDC",
+    sign: 1,
+    position: "0.5",
+    avg_entry_price: "100",
+    position_value: "50",
+    unrealized_pnl: "0",
+    realized_pnl: "0",
+    ...overrides,
+  } as LighterPosition;
+}
+
+describe("toAccountSnapshot", () => {
+  it("includes positions that match the configured market id regardless of reported symbol format", () => {
+    const snapshot = toAccountSnapshot(
+      "BTC",
+      baseDetails,
+      [
+        createPosition({ market_id: 101, symbol: "BTC/USDC:USDC" }),
+        createPosition({ market_id: 202, symbol: "ETH/USDC:USDC", sign: -1 }),
+      ],
+      [],
+      { marketSymbol: "BTC", marketId: 101 }
+    );
+
+    expect(snapshot.positions).toHaveLength(1);
+    expect(snapshot.positions[0]).toMatchObject({ symbol: "BTC", positionAmt: "0.5" });
+  });
+
+  it("falls back to fuzzy symbol matching when market id is unavailable", () => {
+    const snapshot = toAccountSnapshot(
+      "BTC",
+      baseDetails,
+      [
+        createPosition({ market_id: Number.NaN as number, symbol: "BTC/USDC:USDC" }),
+        createPosition({ market_id: Number.NaN as number, symbol: "ETH/USDC:USDC" }),
+      ],
+      [],
+      { marketSymbol: "BTC" }
+    );
+
+    expect(snapshot.positions).toHaveLength(1);
+    expect(snapshot.positions[0]).toMatchObject({ symbol: "BTC", positionAmt: "0.5" });
+  });
+});