Properly "handle" MOJO_RESULT_BUSY in a few flaces.

mojo/public/cpp/system/tests/core_unittest.cc

 // Copyright 2014 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.
 
 // This file tests the C++ Mojo system core wrappers.
 // TODO(vtl): Maybe rename "CoreCppTest" -> "CoreTest" if/when this gets
 // compiled into a different binary from the C API tests.
 
 #include <stddef.h>
 
@@ skipping 475 matching lines @@
 TEST(CoreCppTest, ScopedHandleMoveCtorSelf) {
   ScopedSharedBufferHandle buffer1;
   EXPECT_EQ(MOJO_RESULT_OK, CreateSharedBuffer(nullptr, 1024, &buffer1));
   EXPECT_TRUE(buffer1.is_valid());
 
   buffer1 = buffer1.Pass();
 
   EXPECT_TRUE(buffer1.is_valid());
 }
 
+TEST(CoreCppTest, WaitManyResult) {
+  {
+    WaitManyResult wmr(MOJO_RESULT_OK);
+    EXPECT_FALSE(wmr.IsIndexValid());
+    EXPECT_TRUE(wmr.AreSignalsStatesValid());
+    EXPECT_EQ(MOJO_RESULT_OK, wmr.result);
+  }
+
+  {
+    WaitManyResult wmr(MOJO_RESULT_FAILED_PRECONDITION);
+    EXPECT_FALSE(wmr.IsIndexValid());
+    EXPECT_TRUE(wmr.AreSignalsStatesValid());
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION, wmr.result);
+  }
+
+  {
+    WaitManyResult wmr(MOJO_RESULT_INVALID_ARGUMENT);
+    EXPECT_FALSE(wmr.IsIndexValid());
+    EXPECT_FALSE(wmr.AreSignalsStatesValid());
+    EXPECT_EQ(MOJO_RESULT_INVALID_ARGUMENT, wmr.result);
+  }
+
+  // These should be like "invalid argument".
+  EXPECT_FALSE(
+      WaitManyResult(MOJO_RESULT_RESOURCE_EXHAUSTED).AreSignalsStatesValid());
+  EXPECT_FALSE(WaitManyResult(MOJO_RESULT_BUSY).AreSignalsStatesValid());
+
+  {
+    WaitManyResult wmr(MOJO_RESULT_OK, 5u);
+    EXPECT_TRUE(wmr.IsIndexValid());
+    EXPECT_TRUE(wmr.AreSignalsStatesValid());
+    EXPECT_EQ(MOJO_RESULT_OK, wmr.result);
+    EXPECT_EQ(5u, wmr.index);
+  }
+
+  {
+    WaitManyResult wmr(MOJO_RESULT_FAILED_PRECONDITION, 5u);
+    EXPECT_TRUE(wmr.IsIndexValid());
+    EXPECT_TRUE(wmr.AreSignalsStatesValid());
+    EXPECT_EQ(MOJO_RESULT_FAILED_PRECONDITION, wmr.result);
+    EXPECT_EQ(5u, wmr.index);
+  }
+}
+
 // TODO(vtl): Write data pipe tests.
 
 }  // namespace
 }  // namespace mojo