refractor code to allow more tests

tests/e2e/functional/load-balancing.spec.ts

@@ -0,0 +1,60 @@
+/**
+ * Functional tests: round-robin load balancing across multiple upstreams.
+ *
+ * Creates a proxy host with two echo servers as upstreams. Each server
+ * returns a distinct body so tests can verify that traffic is distributed
+ * across both backends.
+ *
+ * Domain: func-lb.test
+ */
+import { test, expect } from '@playwright/test';
+import { createProxyHost } from '../../helpers/proxy-api';
+import { httpGet, waitForRoute } from '../../helpers/http';
+
+const DOMAIN = 'func-lb.test';
+
+test.describe.serial('Load Balancing (multiple upstreams)', () => {
+  test('setup: create proxy host with two upstreams', async ({ page }) => {
+    await createProxyHost(page, {
+      name: 'Functional LB Test',
+      domain: DOMAIN,
+      // Two upstreams separated by newline — both will be round-robined by Caddy.
+      // echo-server returns "echo-ok", echo-server-2 returns "echo-server-2".
+      upstream: 'echo-server:8080\necho-server-2:8080',
+    });
+    await waitForRoute(DOMAIN);
+  });
+
+  test('all requests return 200', async () => {
+    for (let i = 0; i < 5; i++) {
+      const res = await httpGet(DOMAIN, '/');
+      expect(res.status).toBe(200);
+    }
+  });
+
+  test('both upstreams are reached over multiple requests', async () => {
+    const bodies = new Set<string>();
+
+    // Send enough requests that both backends should be hit via round-robin.
+    for (let i = 0; i < 20; i++) {
+      const res = await httpGet(DOMAIN, '/');
+      if (res.body.includes('echo-ok') || res.body.includes('echo-server-2')) {
+        bodies.add(res.body.trim());
+      }
+    }
+
+    // Both distinct responses must appear
+    expect(bodies.size).toBeGreaterThanOrEqual(2);
+    const arr = Array.from(bodies);
+    expect(arr.some((b) => b.includes('echo-ok'))).toBe(true);
+    expect(arr.some((b) => b.includes('echo-server-2'))).toBe(true);
+  });
+
+  test('different paths all return 200', async () => {
+    const paths = ['/', '/api/test', '/some/deep/path', '/health'];
+    for (const path of paths) {
+      const res = await httpGet(DOMAIN, path);
+      expect(res.status).toBe(200);
+    }
+  });
+});