SnowLuma v2.4.2 source snapshot

packages/core/tests/webui-debug-stream.test.ts

@@ -0,0 +1,56 @@
+import { describe, it, expect } from 'vitest';
+import { createFramePusher } from '../src/webui/debug-stream';
+
+function harness(sizes: number[]) {
+    // desiredSize() returns the next scripted value each call.
+    let i = 0;
+    const frames: string[] = [];
+    const push = createFramePusher({
+        desiredSize: () => (i < sizes.length ? sizes[i++] : (sizes[sizes.length - 1] ?? 1)),
+        enqueue: (chunk) => {
+            frames.push(Buffer.from(chunk).toString());
+        },
+        encode: (s) => Buffer.from(s),
+    });
+    return { push, frames };
+}
+
+describe('createFramePusher', () => {
+    it('enqueues an SSE data frame when there is headroom', () => {
+        const { push, frames } = harness([1]);
+        push({ kind: 'event', x: 1 });
+        expect(frames).toEqual([`data: ${JSON.stringify({ kind: 'event', x: 1 })}\n\n`]);
+    });
+
+    it('drops under backpressure (desiredSize <= 0) without enqueuing', () => {
+        const { push, frames } = harness([0, -3]);
+        push({ a: 1 });
+        push({ a: 2 });
+        expect(frames).toEqual([]);
+    });
+
+    it('emits a coalesced dropped marker before the next delivered frame', () => {
+        const { push, frames } = harness([0, 0, 5]); // drop, drop, then headroom
+        push({ a: 1 });
+        push({ a: 2 });
+        push({ a: 3 });
+        expect(frames).toEqual([
+            `data: ${JSON.stringify({ kind: 'dropped', count: 2 })}\n\n`,
+            `data: ${JSON.stringify({ a: 3 })}\n\n`,
+        ]);
+    });
+
+    it('treats null desiredSize as always-deliver (no backpressure signal)', () => {
+        let i = 0;
+        const frames: string[] = [];
+        const push = createFramePusher({
+            desiredSize: () => (i++ === 0 ? null : 1),
+            enqueue: (chunk) => {
+                frames.push(Buffer.from(chunk).toString());
+            },
+            encode: (s) => Buffer.from(s),
+        });
+        push({ a: 1 });
+        expect(frames).toHaveLength(1);
+    });
+});