diff --git a/types/custom-functions-runtime/custom-functions-runtime-tests.ts b/types/custom-functions-runtime/custom-functions-runtime-tests.ts
index 335e5a1f95..c35c172d7c 100644
--- a/types/custom-functions-runtime/custom-functions-runtime-tests.ts
+++ b/types/custom-functions-runtime/custom-functions-runtime-tests.ts
@@ -7,27 +7,55 @@ 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/${ticker}`)).json();
-    return dollars;
+function stockPriceStream(
+    ticker: string,
+    handler: CustomFunctions.StreamingHandler<number>
+) {
+    const updateFrequency = 10 /* milliseconds*/;
+    let isPending = false;
+
+    const timer = setInterval(async () => {
+        // If there is already a pending request, skip this iteration:
+        if (isPending) {
+            return;
+        }
+
+        const url = `myService.com/prices/${ticker}`;
+        isPending = true;
+        try {
+            const response = await fetch(url);
+            const data = await response.json();
+            handler.setResult(data.price);
+        } catch (error) {
+            handler.setResult(error);
+        }
+        isPending = false;
+    }, updateFrequency);
+
+    handler.onCanceled = () => {
+        clearInterval(timer);
+    };
 }
 
-declare function pause(ms: number): Promise<void>;
+declare function pause(ms: number): Promise<undefined>;
diff --git a/types/custom-functions-runtime/index.d.ts b/types/custom-functions-runtime/index.d.ts
index 8771ab8755..58acfaa6c0 100644
--- a/types/custom-functions-runtime/index.d.ts
+++ b/types/custom-functions-runtime/index.d.ts
@@ -24,7 +24,7 @@ declare namespace CustomFunctions {
          * Sets the returned result for a streaming custom function.
          * @beta
          */
-        setResult: (value: T) => void;
+        setResult: (value: T | Error) => void;
     }
 
     interface CancelableHandler {
diff --git a/types/custom-functions-runtime/tslint.json b/types/custom-functions-runtime/tslint.json
index a62d0d4e68..ad17c76132 100644
--- a/types/custom-functions-runtime/tslint.json
+++ b/types/custom-functions-runtime/tslint.json
@@ -1,6 +1,7 @@
 {
     "extends": "dtslint/dt.json",
     "rules": {
-        "ban-types": false
+        "ban-types": false,
+        "file-name-casing": false
     }
 }