1 files changed, 24 insertions, 0 deletions
diff --git a/js/metrics_test.ts b/js/metrics_test.ts
new file mode 100644
index 000000000..6954ae2ce
--- /dev/null
+++ b/js/metrics_test.ts
@@ -0,0 +1,24 @@
+// Copyright 2018 the Deno authors. All rights reserved. MIT license.
+import { test, assert } from "./test_util.ts";
+import * as deno from "deno";
+
+test(function metrics() {
+  const m1 = deno.metrics();
+  assert(m1.opsDispatched > 0);
+  assert(m1.opsCompleted > 0);
+  assert(m1.bytesSentControl > 0);
+  assert(m1.bytesSentData >= 0);
+  assert(m1.bytesReceived > 0);
+
+  // Write to stdout to ensure a "data" message gets sent instead of just
+  // control messages.
+  const dataMsg = new Uint8Array([41, 42, 43]);
+  deno.stdout.write(dataMsg);
+
+  const m2 = deno.metrics();
+  assert(m2.opsDispatched > m1.opsDispatched);
+  assert(m2.opsCompleted > m1.opsCompleted);
+  assert(m2.bytesSentControl > m1.bytesSentControl);
+  assert(m2.bytesSentData >= m1.bytesSentData + dataMsg.byteLength);
+  assert(m2.bytesReceived > m1.bytesReceived);
+});