1 files changed, 124 insertions, 0 deletions
diff --git a/testing/web-platform/tests/streams/writable-streams/count-queuing-strategy.any.js b/testing/web-platform/tests/streams/writable-streams/count-queuing-strategy.any.js
new file mode 100644
index 0000000000..064e16e815
--- /dev/null
+++ b/testing/web-platform/tests/streams/writable-streams/count-queuing-strategy.any.js
@@ -0,0 +1,124 @@
+// META: global=window,worker
+'use strict';
+
+test(() => {
+  new WritableStream({}, new CountQueuingStrategy({ highWaterMark: 4 }));
+}, 'Can construct a writable stream with a valid CountQueuingStrategy');
+
+promise_test(() => {
+  const dones = Object.create(null);
+
+  const ws = new WritableStream(
+    {
+      write(chunk) {
+        return new Promise(resolve => {
+          dones[chunk] = resolve;
+        });
+      }
+    },
+    new CountQueuingStrategy({ highWaterMark: 0 })
+  );
+
+  const writer = ws.getWriter();
+  let writePromiseB;
+  let writePromiseC;
+
+  return Promise.resolve().then(() => {
+    assert_equals(writer.desiredSize, 0, 'desiredSize should be initially 0');
+
+    const writePromiseA = writer.write('a');
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after 1st write()');
+
+    writePromiseB = writer.write('b');
+    assert_equals(writer.desiredSize, -2, 'desiredSize should be -2 after 2nd write()');
+
+    dones.a();
+    return writePromiseA;
+  }).then(() => {
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after completing 1st write()');
+
+    dones.b();
+    return writePromiseB;
+  }).then(() => {
+    assert_equals(writer.desiredSize, 0, 'desiredSize should be 0 after completing 2nd write()');
+
+    writePromiseC = writer.write('c');
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after 3rd write()');
+
+    dones.c();
+    return writePromiseC;
+  }).then(() => {
+    assert_equals(writer.desiredSize, 0, 'desiredSize should be 0 after completing 3rd write()');
+  });
+}, 'Correctly governs the value of a WritableStream\'s state property (HWM = 0)');
+
+promise_test(() => {
+  const dones = Object.create(null);
+
+  const ws = new WritableStream(
+    {
+      write(chunk) {
+        return new Promise(resolve => {
+          dones[chunk] = resolve;
+        });
+      }
+    },
+    new CountQueuingStrategy({ highWaterMark: 4 })
+  );
+
+  const writer = ws.getWriter();
+  let writePromiseB;
+  let writePromiseC;
+  let writePromiseD;
+
+  return Promise.resolve().then(() => {
+    assert_equals(writer.desiredSize, 4, 'desiredSize should be initially 4');
+
+    const writePromiseA = writer.write('a');
+    assert_equals(writer.desiredSize, 3, 'desiredSize should be 3 after 1st write()');
+
+    writePromiseB = writer.write('b');
+    assert_equals(writer.desiredSize, 2, 'desiredSize should be 2 after 2nd write()');
+
+    writePromiseC = writer.write('c');
+    assert_equals(writer.desiredSize, 1, 'desiredSize should be 1 after 3rd write()');
+
+    writePromiseD = writer.write('d');
+    assert_equals(writer.desiredSize, 0, 'desiredSize should be 0 after 4th write()');
+
+    writer.write('e');
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after 5th write()');
+
+    writer.write('f');
+    assert_equals(writer.desiredSize, -2, 'desiredSize should be -2 after 6th write()');
+
+    writer.write('g');
+    assert_equals(writer.desiredSize, -3, 'desiredSize should be -3 after 7th write()');
+
+    dones.a();
+    return writePromiseA;
+  }).then(() => {
+    assert_equals(writer.desiredSize, -2, 'desiredSize should be -2 after completing 1st write()');
+
+    dones.b();
+    return writePromiseB;
+  }).then(() => {
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after completing 2nd write()');
+
+    dones.c();
+    return writePromiseC;
+  }).then(() => {
+    assert_equals(writer.desiredSize, 0, 'desiredSize should be 0 after completing 3rd write()');
+
+    writer.write('h');
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after 8th write()');
+
+    dones.d();
+    return writePromiseD;
+  }).then(() => {
+    assert_equals(writer.desiredSize, 0, 'desiredSize should be 0 after completing 4th write()');
+
+    writer.write('i');
+    assert_equals(writer.desiredSize, -1, 'desiredSize should be -1 after 9th write()');
+  });
+}, 'Correctly governs the value of a WritableStream\'s state property (HWM = 4)');