From 7052d4f4b59b37c2489beb885998d6bec8d9402a Mon Sep 17 00:00:00 2001
From: multipleof4 <planetrenox@protonmail.com>
Date: Thu, 13 Nov 2025 19:19:01 -0800
Subject: [PATCH] Refactor: remove explicit CDN hint

---
 tests/9_stream_visualizer/test.js | 46 +++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 tests/9_stream_visualizer/test.js

diff --git a/tests/9_stream_visualizer/test.js b/tests/9_stream_visualizer/test.js
new file mode 100644
index 0000000..8bc6654
--- /dev/null
+++ b/tests/9_stream_visualizer/test.js
@@ -0,0 +1,46 @@
+export default{
+  functionName:'createStreamVisualizer',
+  prompt:`// Write an async function 'createStreamVisualizer' that consumes a streaming time-series feed and prepares chart data.
+// - Accept (asyncIterable, options) where options = { maxPoints, alpha, width, height, yDomain:[min,max] }.
+// - Use dynamic import() to load D3 for scales, line generator, etc.
+// - Consume the async iterable with 'for await', applying an exponential moving average: ema = alpha * value + (1 - alpha) * prevEma (seed with first value).
+// - Keep only the latest 'maxPoints' entries. Each stored point must be { timestamp, value, ema }.
+// - Build linear x/y scales (timestamp domain from first/last retained point, yDomain from options) and generate an SVG path string using d3.line on the EMA values.
+// - Return { data, path } once the stream completes. 'data' is the capped array; 'path' is the SVG path string ready for a <path d="">.`,
+
+  runTest:async createStreamVisualizer=>{
+    const assert={
+      strictEqual:(a,e,m)=>{if(a!==e)throw new Error(m||`${a}!==${e}`)},
+      ok:(c,m)=>{if(!c)throw new Error(m)}
+    };
+    const samples=[
+      {timestamp:0,value:10},
+      {timestamp:1e3,value:20},
+      {timestamp:2e3,value:15},
+      {timestamp:3e3,value:30},
+      {timestamp:4e3,value:25},
+      {timestamp:5e3,value:40}
+    ];
+    async function*mockStream(){
+      for(const point of samples)yield {...point};
+    }
+    const opts={maxPoints:4,alpha:.4,width:400,height:200,yDomain:[0,50]};
+    const expected=[
+      {timestamp:2e3,value:15,ema:14.4},
+      {timestamp:3e3,value:30,ema:20.64},
+      {timestamp:4e3,value:25,ema:22.384},
+      {timestamp:5e3,value:40,ema:29.4304}
+    ];
+    const {data,path}=await createStreamVisualizer(mockStream(),opts);
+    assert.strictEqual(Array.isArray(data),true,'data must be an array');
+    assert.strictEqual(data.length,opts.maxPoints,'Should keep only latest maxPoints entries');
+    const withinTol=(a,b,t=1e-3)=>Math.abs(a-b)<=t;
+    data.forEach((row,i)=>{
+      const exp=expected[i];
+      assert.strictEqual(row.timestamp,exp.timestamp,'Timestamp mismatch');
+      assert.strictEqual(row.value,exp.value,'Value mismatch');
+      if(!withinTol(row.ema,exp.ema))throw new Error(`EMA mismatch at index ${i}: ${row.ema} vs ${exp.ema}`);
+    });
+    assert.ok(typeof path==='string'&&path.startsWith('M')&&path.includes('L'),'Path should be a valid SVG polyline string');
+  }
+};