From 4fbc05367d3ea08a87aed4c9191247faf7a0e474 Mon Sep 17 00:00:00 2001
From: Anikesh Thakur <Anikesh348@users.noreply.github.com>
Date: Tue, 22 Sep 2026 17:10:04 +0000
Subject: [PATCH] fix: normalize Binance feed symbol case

---
 core/src/feeds/binance/binance-feed.ts |  7 ++--
 core/test/unit/dataFeeds.core.test.ts  | 44 ++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/core/src/feeds/binance/binance-feed.ts b/core/src/feeds/binance/binance-feed.ts
index a9020cb6..f6548fd1 100644
--- a/core/src/feeds/binance/binance-feed.ts
+++ b/core/src/feeds/binance/binance-feed.ts
@@ -100,7 +100,8 @@ export class BinanceFeed extends BaseDataFeed {
     }
 
     protected async fetchTickerImpl(symbol: string): Promise<Ticker> {
-        const cached = this.latestTickers.get(symbol);
+        const normalizedSymbol = symbol.toUpperCase();
+        const cached = this.latestTickers.get(normalizedSymbol);
         if (cached) return cached;
 
         await this.ensureConnected();
@@ -110,7 +111,7 @@ export class BinanceFeed extends BaseDataFeed {
                 reject(new Error(`BinanceFeed: timed out waiting for trade on ${symbol} (10s)`));
             }, 10_000);
 
-            const cleanup = this.watchTickerImpl(symbol, (ticker) => {
+            const cleanup = this.watchTickerImpl(normalizedSymbol, (ticker) => {
                 clearTimeout(timeout);
                 cleanup();
                 resolve(ticker);
@@ -130,7 +131,7 @@ export class BinanceFeed extends BaseDataFeed {
     }
 
     protected watchTickerImpl(symbol: string, callback: (ticker: Ticker) => void): () => void {
-        const sub: Subscription = { symbol, callback };
+        const sub: Subscription = { symbol: symbol.toUpperCase(), callback };
         this.subscriptions.push(sub);
         this.ensureConnected().catch((err: unknown) => {
             logger.error('[BinanceFeed] initial connect failed in watchTickerImpl', {
diff --git a/core/test/unit/dataFeeds.core.test.ts b/core/test/unit/dataFeeds.core.test.ts
index aa30892c..d45bdf62 100644
--- a/core/test/unit/dataFeeds.core.test.ts
+++ b/core/test/unit/dataFeeds.core.test.ts
@@ -1,6 +1,23 @@
 import { ExchangeNotAvailable, NotSupported } from '../../src/errors';
 import { BinanceFeed } from '../../src/feeds/binance';
+import { normalizeTradeToTicker } from '../../src/feeds/binance/normalizer';
+import { BinanceRelayTradeEvent } from '../../src/feeds/binance/types';
 import { ChainlinkFeed } from '../../src/feeds/chainlink/chainlink-feed';
+import { Ticker } from '../../src/feeds/types';
+
+class TestBinanceFeed extends BinanceFeed {
+    async connect(): Promise<void> {}
+
+    cacheTicker(ticker: Ticker): void {
+        const internals = this as unknown as { latestTickers: Map<string, Ticker> };
+        internals.latestTickers.set(ticker.symbol, ticker);
+    }
+
+    emitTrade(event: BinanceRelayTradeEvent): void {
+        const internals = this as unknown as { handleMessage(data: string): void };
+        internals.handleMessage(JSON.stringify(event));
+    }
+}
 
 describe('Data feed backend errors', () => {
     test('Binance fetchTicker names the missing relay URL setting', async () => {
@@ -22,6 +39,33 @@ describe('Data feed backend errors', () => {
         } satisfies Partial<NotSupported>);
     });
 
+    test('Binance normalizes symbol case for cached and watched tickers', async () => {
+        const feed = new TestBinanceFeed({ wsUrl: '', apiKey: '' });
+        const event: BinanceRelayTradeEvent = {
+            op: 'event',
+            source: 'binance',
+            symbol: 'BTCUSDT',
+            trade_id: 1,
+            price: '65000',
+            quantity: '0.01',
+            event_time_ms: 1_700_000_000_000,
+            trade_time_ms: 1_700_000_000_000,
+            is_buyer_maker: false,
+            timestamp_received_ms: 1_700_000_000_001,
+        };
+        const ticker = normalizeTradeToTicker(event);
+        feed.cacheTicker(ticker);
+
+        await expect(feed.fetchTicker('btc/usdt')).resolves.toBe(ticker);
+
+        const callback = jest.fn();
+        const unsubscribe = feed.watchTicker('btc/usdt', callback);
+        feed.emitTrade(event);
+
+        expect(callback).toHaveBeenCalledWith(expect.objectContaining({ symbol: 'BTC/USDT' }));
+        unsubscribe();
+    });
+
     test('Chainlink oracle calls name the missing REST API URL setting', async () => {
         const feed = new ChainlinkFeed({ baseUrl: '', apiKey: '', wsUrl: '' });