diff --git a/posix.h b/posix.h
index 70a0db1a..068f6638 100644
--- a/posix.h
+++ b/posix.h
@@ -41,10 +41,6 @@
 
 #include "format.h"
 
-#ifdef FMT_INCLUDE_POSIX_TEST
-# include "test/posix-test.h"
-#endif
-
 #ifndef FMT_POSIX
 # if defined(_WIN32) && !defined(__MINGW32__)
 // Fix warnings about deprecated symbols.
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 6eaddb80..73ac11d2 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -62,9 +62,7 @@ add_executable(macro-test macro-test.cc ${FMT_TEST_SOURCES} ${TEST_MAIN_SRC})
 target_link_libraries(macro-test gmock)
 
 if (HAVE_OPEN)
-  add_executable(posix-test posix-test.cc ${FMT_TEST_SOURCES} ${TEST_MAIN_SRC})
-  set_target_properties(posix-test
-    PROPERTIES COMPILE_DEFINITIONS "FMT_INCLUDE_POSIX_TEST=1")
+  add_executable(posix-test posix-mock-test.cc ../format.cc ${TEST_MAIN_SRC})
   target_link_libraries(posix-test gmock)
   add_test(NAME posix-test COMMAND posix-test)
 endif ()
diff --git a/test/posix-test.cc b/test/posix-mock-test.cc
similarity index 98%
rename from test/posix-test.cc
rename to test/posix-mock-test.cc
index a914ae7b..efd47e21 100644
--- a/test/posix-test.cc
+++ b/test/posix-mock-test.cc
@@ -1,7 +1,7 @@
 /*
- Test wrappers around POSIX functions.
+ Tests of the C++ interface to POSIX functions that require mocks
 
- Copyright (c) 2012-2014, Victor Zverovich
+ Copyright (c) 2012-2015, Victor Zverovich
  All rights reserved.
 
  Redistribution and use in source and binary forms, with or without
@@ -28,7 +28,8 @@
 // Disable bogus MSVC warnings.
 #define _CRT_SECURE_NO_WARNINGS
 
-#include "posix-test.h"
+#include "posix-mock.h"
+#include "posix.cc"
 
 #include <errno.h>
 #include <fcntl.h>
diff --git a/test/posix-test.h b/test/posix-mock.h
similarity index 96%
rename from test/posix-test.h
rename to test/posix-mock.h
index 19b3e76f..32dd6639 100644
--- a/test/posix-test.h
+++ b/test/posix-mock.h
@@ -1,7 +1,7 @@
 /*
- Test wrappers around POSIX functions.
+ Mocks of POSIX functions
 
- Copyright (c) 2012-2014, Victor Zverovich
+ Copyright (c) 2012-2015, Victor Zverovich
  All rights reserved.
 
  Redistribution and use in source and binary forms, with or without