fix warning tmpnam

tests/CMakeLists.txt

@@ -35,3 +35,4 @@ pip_test(math)
 pip_test(core)
 pip_test(piobject)
 pip_test(client_server pip_client_server)
+pip_test(io)

tests/io/testpifile.cpp

@@ -0,0 +1,14 @@
+#include "pifile.h"
+
+#include "gtest/gtest.h"
+
+TEST(PIFile_Test, openTemporary) {
+	const auto ba = PIByteArray::fromHex("AABBCC");
+	PIFile f;
+	ASSERT_TRUE(f.openTemporary());
+	ASSERT_TRUE(f.path().isNotEmpty());
+	ASSERT_EQ(ba.size(), f.write(ba));
+	ASSERT_EQ(ba, f.readAll());
+	ASSERT_TRUE(f.close());
+}
+