[libFuzzer] add a missing test file

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244151 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Fuzzer/test/StrcmpTest.cpp

@@ -0,0 +1,28 @@
+// Break through a series of strcmp.
+#include <cstring>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cassert>
+
+bool Eq(const uint8_t *Data, size_t Size, const char *Str) {
+  char Buff[1024];
+  size_t Len = strlen(Str);
+  if (Size < Len) return false;
+  if (Len >= sizeof(Buff)) return false;
+  memcpy(Buff, (char*)Data, Len);
+  Buff[Len] = 0;
+  int res = strcmp(Buff, Str);
+  return res == 0;
+}
+
+extern "C" void LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  if (Eq(Data, Size, "AAA") &&
+      Size >= 3 && Eq(Data + 3, Size - 3, "BBBB") &&
+      Size >= 7 && Eq(Data + 7, Size - 7, "CCCCCC") &&
+      Size >= 14 && Data[13] == 42
+    ) {
+    fprintf(stderr, "BINGO\n");
+    exit(1);
+  }
+}