Mojo: First stab at making MessagePipes work across OS pipes.

mojo/system/message_pipe_dispatcher_unittest.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // NOTE(vtl): Some of these tests are inherently flaky (e.g., if run on a
 // heavily-loaded system). Sorry. |kEpsilonMicros| may be increased to increase
 // tolerance and reduce observed flakiness.
 
 #include "mojo/system/message_pipe_dispatcher.h"
 
@@ skipping 193 matching lines @@
     EXPECT_EQ(MOJO_RESULT_OK,
               d_1->WriteMessage(buffer, kBufferSize,
                                 NULL, 0,
                                 MOJO_WRITE_MESSAGE_FLAG_NONE));
 
     // Try waiting for readable on |d_0|; should fail (already satisfied).
     w.Init();
     EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
               d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 0));
 
+    // Try reading from |d_1|; should fail (nothing to read).
+    buffer[0] = 0;
+    buffer_size = kBufferSize;
+    EXPECT_EQ(MOJO_RESULT_NOT_FOUND,
+              d_1->ReadMessage(buffer, &buffer_size,
+                               NULL, NULL,
+                               MOJO_READ_MESSAGE_FLAG_NONE));
+
     // Close |d_1|.
     EXPECT_EQ(MOJO_RESULT_OK, d_1->Close());
 
     // Try waiting for readable on |d_0|; should fail (already satisfied).
     w.Init();
     EXPECT_EQ(MOJO_RESULT_ALREADY_EXISTS,
               d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 1));
 
     // Read from |d_0|.
     buffer[0] = 0;
@@ skipping 23 matching lines @@
     // Try waiting for readable on |d_0|; should fail (unsatisfiable).
     w.Init();
     EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
               d_0->AddWaiter(&w, MOJO_WAIT_FLAG_READABLE, 3));
 
     // Try waiting for writable on |d_0|; should fail (unsatisfiable).
     w.Init();
     EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
               d_0->AddWaiter(&w, MOJO_WAIT_FLAG_WRITABLE, 4));
 
-    // Try reading from |d_0|; should fail (nothing to read).
+    // Try reading from |d_0|; should fail (nothing to read and other end
+    // closed).
     buffer[0] = 0;
     buffer_size = kBufferSize;
-    EXPECT_EQ(MOJO_RESULT_NOT_FOUND,
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
               d_0->ReadMessage(buffer, &buffer_size,
                                NULL, NULL,
                                MOJO_READ_MESSAGE_FLAG_NONE));
 
     // Try writing to |d_0|; should fail (other end closed).
     buffer[0] = 345678901;
     EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION,
               d_0->WriteMessage(buffer, kBufferSize,
                                 NULL, 0,
                                 MOJO_WRITE_MESSAGE_FLAG_NONE));
@@ skipping 325 matching lines @@
   EXPECT_EQ(total_messages_written, total_messages_read);
   EXPECT_EQ(total_bytes_written, total_bytes_read);
 
   EXPECT_EQ(MOJO_RESULT_OK, d_write->Close());
   EXPECT_EQ(MOJO_RESULT_OK, d_read->Close());
 }
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo