Update tests to allow a streaming error, and general test cleanup

types/custom-functions-runtime/custom-functions-runtime-tests.ts

@@ -7,27 +7,61 @@ CustomFunctionMappings = {
     addTen: ADD10
 };
 
-async function getStockValues(ticker: string, handler: CustomFunctions.StreamingHandler<number>) {
-    const dollars = await (await fetch(`myService.com/prices/${ticker}`)).json();
-        handler.setResult(dollars);
+async function getStockValues(ticker: string): Promise<number> {
+    const response = await fetch(`myService.com/prices/${ticker}`);
+    return (await response.json())['price'];
 }
 
-async function getStockValuesOneTime(ticker: string, handler: CustomFunctions.CancelableHandler) {
+async function getStockValuesCancellable(
+    ticker: string,
+    handler: CustomFunctions.CancelableHandler
+): Promise<number> {
     let shouldStop = false;
-    handler.onCanceled = () => shouldStop = true;
+    handler.onCanceled = () => (shouldStop = true);
     await pause(1000);
 
     if (shouldStop) {
         return null;
     }
 
-      const dollars = await (await fetch(`myService.com/prices/${ticker}`)).json();
-        return dollars;
+    const response = await fetch(`myService.com/prices/${ticker}`);
+    return (await response.json())['price'];
 }
 
-async function getStockValuesNowWithNoCancelling(ticker: string) {
-    const dollars = await (await fetch(`myService.com/prices/${ticker}`)).json();
-    return dollars;
+async function stockPriceStream(
+    ticker: string,
+    handler: CustomFunctions.StreamingHandler<number>
+) {
+    var updateFrequency = 10 /* milliseconds*/;
+    var isPending = false;
+
+    var timer = setInterval(function() {
+        // If there is already a pending request, skip this iteration:
+        if (isPending) {
+            return;
+        }
+
+        var url = `myService.com/prices/${ticker}`;
+        isPending = true;
+
+        fetch(url)
+            .then(function(response) {
+                return response.json();
+            })
+            .then(function(data) {
+                handler.setResult(data.price);
+            })
+            .catch(function(error) {
+                handler.setResult(new Error(error));
+            })
+            .then(function() {
+                isPending = false;
+            });
+    }, updateFrequency);
+
+    handler.onCanceled = () => {
+        clearInterval(timer);
+    };
 }
 
 declare function pause(ms: number): Promise<void>;