1 files changed, 68 insertions, 0 deletions
diff --git a/std/node/_stream/transform_test.ts b/std/node/_stream/transform_test.ts
new file mode 100644
index 000000000..d3b90ff01
--- /dev/null
+++ b/std/node/_stream/transform_test.ts
@@ -0,0 +1,68 @@
+// Copyright Node.js contributors. All rights reserved. MIT License.
+import { Buffer } from "../buffer.ts";
+import Transform from "./transform.ts";
+import finished from "./end_of_stream.ts";
+import { deferred } from "../../async/mod.ts";
+import { assert, assertEquals } from "../../testing/asserts.ts";
+
+Deno.test("Transform stream finishes correctly", async () => {
+  let finishedExecuted = 0;
+  const finishedExecutedExpected = 1;
+  const finishedExecution = deferred();
+
+  const tr = new Transform({
+    transform(_data, _enc, cb) {
+      cb();
+    },
+  });
+
+  let finish = false;
+  let ended = false;
+
+  tr.on("end", () => {
+    ended = true;
+  });
+
+  tr.on("finish", () => {
+    finish = true;
+  });
+
+  finished(tr, (err) => {
+    finishedExecuted++;
+    if (finishedExecuted === finishedExecutedExpected) {
+      finishedExecution.resolve();
+    }
+    assert(!err, "no error");
+    assert(finish);
+    assert(ended);
+  });
+
+  tr.end();
+  tr.resume();
+
+  const finishedTimeout = setTimeout(
+    () => finishedExecution.reject(),
+    1000,
+  );
+  await finishedExecution;
+  clearTimeout(finishedTimeout);
+  assertEquals(finishedExecuted, finishedExecutedExpected);
+});
+
+Deno.test("Transform stream flushes data correctly", () => {
+  const expected = "asdf";
+
+  const t = new Transform({
+    transform: (_d, _e, n) => {
+      n();
+    },
+    flush: (n) => {
+      n(null, expected);
+    },
+  });
+
+  t.end(Buffer.from("blerg"));
+  t.on("data", (data) => {
+    assertEquals(data.toString(), expected);
+  });
+});