diff --git a/toolkit/components/osfile/tests/xpcshell/test_osfile_async_setDates.js b/toolkit/components/osfile/tests/xpcshell/test_osfile_async_setDates.js
new file mode 100644
index 00000000000..4f6e02a2f3c
--- /dev/null
+++ b/toolkit/components/osfile/tests/xpcshell/test_osfile_async_setDates.js
@@ -0,0 +1,208 @@
+"use strict";
+
+Components.utils.import("resource://gre/modules/osfile.jsm");
+Components.utils.import("resource://gre/modules/Task.jsm");
+
+/**
+ * A test to ensure that OS.File.setDates and OS.File.prototype.setDates are
+ * working correctly.
+ * (see bug 924916)
+ */
+
+function run_test() {
+  do_test_pending();
+  run_next_test();
+}
+
+// Non-prototypical tests, operating on path names.
+add_task(function test_nonproto() {
+  // First, create a file we can mess with.
+  let path = OS.Path.join(OS.Constants.Path.tmpDir,
+                              "test_osfile_async_setDates_nonproto.tmp");
+  yield OS.File.writeAtomic(path, new Uint8Array(1));
+
+  try {
+    // 1. Try to set some well known dates.
+    // We choose multiples of 2000ms, because the time stamp resolution of
+    // the underlying OS might not support something more precise.
+    const accDate = 2000;
+    const modDate = 4000;
+    {
+      yield OS.File.setDates(path, accDate, modDate);
+      let stat = yield OS.File.stat(path);
+      do_check_eq(accDate, stat.lastAccessDate.getTime());
+      do_check_eq(modDate, stat.lastModificationDate.getTime());
+    }
+
+    // 2.1 Try to omit modificationDate (which should then default to
+    // |Date.now()|, expect for resolution differences).
+    {
+      yield OS.File.setDates(path, accDate);
+      let stat = yield OS.File.stat(path);
+      do_check_eq(accDate, stat.lastAccessDate.getTime());
+      do_check_neq(modDate, stat.lastModificationDate.getTime());
+    }
+
+    // 2.2 Try to omit accessDate as well (which should then default to
+    // |Date.now()|, expect for resolution differences).
+    {
+      yield OS.File.setDates(path);
+      let stat = yield OS.File.stat(path);
+      do_check_neq(accDate, stat.lastAccessDate.getTime());
+      do_check_neq(modDate, stat.lastModificationDate.getTime());
+    }
+
+    // 3. Repeat 1., but with Date objects this time
+    {
+      yield OS.File.setDates(path, new Date(accDate), new Date(modDate));
+      let stat = yield OS.File.stat(path);
+      do_check_eq(accDate, stat.lastAccessDate.getTime());
+      do_check_eq(modDate, stat.lastModificationDate.getTime());
+    }
+
+    // 4. Check that invalid params will cause an exception/rejection.
+    {
+      for (let p of ["invalid", new Uint8Array(1), NaN]) {
+        try {
+          yield OS.File.setDates(path, p, modDate);
+          do_throw("Invalid access date should have thrown for: " + p);
+        } catch (ex) {
+          let stat = yield OS.File.stat(path);
+          do_check_eq(accDate, stat.lastAccessDate.getTime());
+          do_check_eq(modDate, stat.lastModificationDate.getTime());
+        }
+        try {
+          yield OS.File.setDates(path, accDate, p);
+          do_throw("Invalid modification date should have thrown for: " + p);
+        } catch (ex) {
+          let stat = yield OS.File.stat(path);
+          do_check_eq(accDate, stat.lastAccessDate.getTime());
+          do_check_eq(modDate, stat.lastModificationDate.getTime());
+        }
+        try {
+          yield OS.File.setDates(path, p, p);
+          do_throw("Invalid dates should have thrown for: " + p);
+        } catch (ex) {
+          let stat = yield OS.File.stat(path);
+          do_check_eq(accDate, stat.lastAccessDate.getTime());
+          do_check_eq(modDate, stat.lastModificationDate.getTime());
+        }
+      }
+    }
+  } finally {
+    // Remove the temp file again
+    yield OS.File.remove(path);
+  }
+});
+
+// Prototypical tests, operating on |File| handles.
+add_task(function test_proto() {
+  // First, create a file we can mess with.
+  let path = OS.Path.join(OS.Constants.Path.tmpDir,
+                              "test_osfile_async_setDates_proto.tmp");
+  yield OS.File.writeAtomic(path, new Uint8Array(1));
+
+  try {
+    let fd = yield OS.File.open(path, {write: true});
+
+    try {
+      // 1. Try to set some well known dates.
+      // We choose multiples of 2000ms, because the time stamp resolution of
+      // the underlying OS might not support something more precise.
+      const accDate = 2000;
+      const modDate = 4000;
+      {
+        yield fd.setDates(accDate, modDate);
+        let stat = yield fd.stat();
+        do_check_eq(accDate, stat.lastAccessDate.getTime());
+        do_check_eq(modDate, stat.lastModificationDate.getTime());
+      }
+
+      // 2.1 Try to omit modificationDate (which should then default to
+      // |Date.now()|, expect for resolution differences).
+      {
+        yield fd.setDates(accDate);
+        let stat = yield fd.stat();
+        do_check_eq(accDate, stat.lastAccessDate.getTime());
+        do_check_neq(modDate, stat.lastModificationDate.getTime());
+      }
+
+      // 2.2 Try to omit accessDate as well (which should then default to
+      // |Date.now()|, expect for resolution differences).
+      {
+        yield fd.setDates();
+        let stat = yield fd.stat();
+        do_check_neq(accDate, stat.lastAccessDate.getTime());
+        do_check_neq(modDate, stat.lastModificationDate.getTime());
+      }
+
+      // 3. Repeat 1., but with Date objects this time
+      {
+        yield fd.setDates(new Date(accDate), new Date(modDate));
+        let stat = yield fd.stat();
+        do_check_eq(accDate, stat.lastAccessDate.getTime());
+        do_check_eq(modDate, stat.lastModificationDate.getTime());
+      }
+
+      // 4. Check that invalid params will cause an exception/rejection.
+      {
+        for (let p of ["invalid", new Uint8Array(1), NaN]) {
+          try {
+            yield fd.setDates(p, modDate);
+            do_throw("Invalid access date should have thrown for: " + p);
+          } catch (ex) {
+            let stat = yield fd.stat();
+            do_check_eq(accDate, stat.lastAccessDate.getTime());
+            do_check_eq(modDate, stat.lastModificationDate.getTime());
+          }
+          try {
+            yield fd.setDates(accDate, p);
+            do_throw("Invalid modification date should have thrown for: " + p);
+          } catch (ex) {
+            let stat = yield fd.stat();
+            do_check_eq(accDate, stat.lastAccessDate.getTime());
+            do_check_eq(modDate, stat.lastModificationDate.getTime());
+          }
+          try {
+            yield fd.setDates(p, p);
+            do_throw("Invalid dates should have thrown for: " + p);
+          } catch (ex) {
+            let stat = yield fd.stat();
+            do_check_eq(accDate, stat.lastAccessDate.getTime());
+            do_check_eq(modDate, stat.lastModificationDate.getTime());
+          }
+        }
+      }
+    } finally {
+      yield fd.close();
+    }
+  } finally {
+    // Remove the temp file again
+    yield OS.File.remove(path);
+  }
+});
+
+// Tests setting dates on directories.
+add_task(function test_dirs() {
+  let path = OS.Path.join(OS.Constants.Path.tmpDir,
+                              "test_osfile_async_setDates_dir");
+  yield OS.File.makeDir(path);
+
+  try {
+    // 1. Try to set some well known dates.
+    // We choose multiples of 2000ms, because the time stamp resolution of
+    // the underlying OS might not support something more precise.
+    const accDate = 2000;
+    const modDate = 4000;
+    {
+      yield OS.File.setDates(path, accDate, modDate);
+      let stat = yield OS.File.stat(path);
+      do_check_eq(accDate, stat.lastAccessDate.getTime());
+      do_check_eq(modDate, stat.lastModificationDate.getTime());
+    }
+  } finally {
+    yield OS.File.removeEmptyDir(path);
+  }
+});
+
+add_task(do_test_finished);
diff --git a/toolkit/components/osfile/tests/xpcshell/xpcshell.ini b/toolkit/components/osfile/tests/xpcshell/xpcshell.ini
index 04180820ed5..dd0f67ff7ef 100644
--- a/toolkit/components/osfile/tests/xpcshell/xpcshell.ini
+++ b/toolkit/components/osfile/tests/xpcshell/xpcshell.ini
@@ -9,6 +9,7 @@ tail =
 [test_osfile_async_bytes.js]
 [test_osfile_async_copy.js]
 [test_osfile_async_flush.js]
+[test_osfile_async_setDates.js]
 [test_profiledir.js]
 [test_logging.js]
 [test_creationDate.js]