[NaCl SDK] nacl_io: Make IRT intercepts (and their test code) more robust.

native_client_sdk/src/tests/nacl_io_test/kernel_wrap_test.cc

 // Copyright (c) 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.
 
 // The linux host build of nacl_io can't do wrapping of syscalls so all
 // these tests must be disabled.
 #if !defined(__linux__)
 
 #include <unistd.h>
 
@@ skipping 91 matching lines @@
 const char* kDummyConstChar3 = "fr00gl3";
 const void* kDummyVoidPtr = "blahblah";
 const uid_t kDummyUid = 1001;
 const gid_t kDummyGid = 1002;
 
 class KernelWrapTest : public ::testing::Test {
  public:
   KernelWrapTest() {}
 
   virtual void SetUp() {
+    // Initialize the global errno value to a consistent value rather than
+    // relying on its value from previous test runs.
+    errno = 0;
+
     // Initializing the KernelProxy opens stdin/stdout/stderr.
     EXPECT_CALL(mock, open(_, _))
         .WillOnce(Return(0))
         .WillOnce(Return(1))
         .WillOnce(Return(2));
     // And will call mount / and /dev.
     EXPECT_CALL(mock, mount(_, _, _, _, _))
         .WillOnce(Return(0))
         .WillOnce(Return(0));
 
@@ skipping 617 matching lines @@
   int dummy_val;
   EXPECT_CALL(mock, socketpair(kDummyInt, kDummyInt2, kDummyInt3, &dummy_val))
       .WillOnce(Return(kDummyInt4));
   EXPECT_EQ(kDummyInt4,
             socketpair(kDummyInt, kDummyInt2, kDummyInt3, &dummy_val));
 }
 
 #endif  // PROVIDES_SOCKET_API
 
 #endif  // __linux__