[libfuzzer] replacing unittest for truncate_units with functional test.

Differential Revision: http://reviews.llvm.org/D20641

llvm-svn: 270755
diff --git a/llvm/lib/Fuzzer/test/EmptyTest.cpp b/llvm/lib/Fuzzer/test/EmptyTest.cpp
new file mode 100644
index 0000000..5e84330
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/EmptyTest.cpp
@@ -0,0 +1,11 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+// A fuzzer with empty target function.
+
+#include <cstdint>
+#include <cstdlib>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  return 0;
+}