ScopedNativeLibrary.Basic test fix

base/scoped_native_library_unittest.cc

 // Copyright (c) 2011 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.
 
 #include "base/scoped_native_library.h"
 #if defined(OS_WIN)
 #include "base/files/file_path.h"
 #endif
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 // Tests whether or not a function pointer retrieved via ScopedNativeLibrary
 // is available only in a scope.
 TEST(ScopedNativeLibrary, Basic) {
 #if defined(OS_WIN)
   // Get the pointer to DirectDrawCreate() from "ddraw.dll" and verify it
   // is valid only in this scope.
   // FreeLibrary() doesn't actually unload a DLL until its reference count
-  // becomes zero, i.e. this function pointer is still valid if the DLL used
+  // becomes zero, i.e. function pointer is still valid if the DLL used
   // in this test is also used by another part of this executable.
   // So, this test uses "ddraw.dll", which is not used by Chrome at all but
   // installed on all versions of Windows.
-  FARPROC test_function;
+  const char kFunctionName[] = "DirectDrawCreate";
+  NativeLibrary native_library;
   {

[cpu_(ooo_6.6-7.5), 2013/10/30 20:08:45]

the code here is different, the scope blocks of 26, 32 in the old code is to (I
assume) force the destruction of |library| so it seems we are testing different
cases.

As for removing IsBadCodePtr yes, please, that function is evil.

[Tomasz Moniuszko, 2013/10/31 09:13:37]

Why do you think we are testing different cases? In new code we also have scope
(lines 27 to 37) and |library| is also destructed.

The difference is in the way of checking if library has been really unloaded.
Old code (line 33) is using IsBadCodePtr() function which randomly returns 0
while test expects non-zero return value. New code (lines 38 and 39) tries to
get function pointer from the library which has been unloaded already
(FreeLibrary() was called in ScopedNativeLibrary destructor making
|native_library| handle invalid).

     FilePath path(GetNativeLibraryName(L"ddraw"));
-    ScopedNativeLibrary library(path);
-    test_function = reinterpret_cast<FARPROC>(
-        library.GetFunctionPointer("DirectDrawCreate"));
+    native_library = LoadNativeLibrary(path, NULL);
+    ScopedNativeLibrary library(native_library);
+    FARPROC test_function =
+        reinterpret_cast<FARPROC>(library.GetFunctionPointer(kFunctionName));
     EXPECT_EQ(0, IsBadCodePtr(test_function));
+    EXPECT_EQ(
+        GetFunctionPointerFromNativeLibrary(native_library, kFunctionName),
+        test_function);
   }
-  EXPECT_NE(0, IsBadCodePtr(test_function));
+  EXPECT_EQ(NULL,
+            GetFunctionPointerFromNativeLibrary(native_library, kFunctionName));
 #endif
 }
 
 }  // namespace base