Added a header to hold the file generation code for unit testing purposes.

test/unit/utDefaultIOStream.cpp

@@ -39,6 +39,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 -------------------------------------------------------------------------*/
 #include <gtest/gtest.h>
 #include "TestIOStream.h"
+#include "UnitTestFileGenerator.h"
 #include <cstdio>
 #include <cstdlib>
 #include <string>
@@ -49,37 +50,6 @@ class utDefaultIOStream : public ::testing::Test {
     // empty
 };
 
-#if defined(__GNUC__) || defined(__clang__)
-#define TMP_PATH "/tmp/"
-FILE* MakeTmpFilePath(char* tmplate)
-{
-    auto fd = mkstemp(tmplate);
-    EXPECT_NE(-1, fd);
-    if(fd == -1)
-    {
-        return nullptr;
-    }
-    auto fs = fdopen(fd, "w+");
-    EXPECT_NE(nullptr, fs);
-    return fs;
-}
-#elif defined(_MSC_VER)
-#include <io.h>
-#define TMP_PATH "./"
-FILE* MakeTmpFilePath(char* tmplate)
-{
-    auto pathtemplate = _mktemp(tmplate);
-    EXPECT_NE(pathtemplate, nullptr);
-    if(pathtemplate == nullptr)
-    {
-        return nullptr;
-    }
-    auto* fs = std::fopen(pathtemplate, "w+");
-    EXPECT_NE(fs, nullptr);
-    return fs;
-}
-#endif
-
 const char data[]{"Lorem ipsum dolor sit amet, consectetur adipiscing elit. Qui\
 sque luctus sem diam, ut eleifend arcu auctor eu. Vestibulum id est vel nulla l\
 obortis malesuada ut sed turpis. Nulla a volutpat tortor. Nunc vestibulum portt\