add socketTimeout functional tests

test/functional/socketTimeout.ts

@@ -0,0 +1,64 @@
+import { expect } from "chai";
+import Redis from "../../lib/Redis";
+
+describe("socketTimeout", () => {
+  const timeoutMs = 500;
+
+  it("should ensure correct startup with password (https://github.com/redis/ioredis/issues/1919)", (done) => {
+    let timeoutObj: NodeJS.Timeout;
+
+    const redis = new Redis({
+      socketTimeout: timeoutMs,
+      lazyConnect: true,
+      password: "foobared",
+    });
+
+    redis.on("error", (err) => {
+      clearTimeout(timeoutObj);
+      done(err.toString());
+    });
+
+    redis.connect(() => {
+      timeoutObj = setTimeout(() => {
+        done();
+      }, timeoutMs * 2);
+    });
+  });
+
+  it("should not throw error when socketTimeout is set and no command is sent", (done) => {
+    let timeoutObj: NodeJS.Timeout;
+
+    const redis = new Redis({
+      socketTimeout: timeoutMs,
+      lazyConnect: true,
+    });
+
+    redis.on("error", (err) => {
+      clearTimeout(timeoutObj);
+      done(err.toString());
+    });
+
+    redis.connect(() => {
+      timeoutObj = setTimeout(() => {
+        done();
+      }, timeoutMs * 2);
+    });
+  });
+
+  it("should throw if socket timeout is reached", (done) => {
+    const redis = new Redis({
+      socketTimeout: timeoutMs,
+      lazyConnect: true,
+    });
+
+    redis.on("error", (err) => {
+      expect(err.message).to.include("Socket timeout");
+      done();
+    });
+
+    redis.connect(() => {
+      redis.stream.removeAllListeners("data");
+      redis.ping();
+    });
+  });
+});