[libc] Make string tests compatible with the Fuchsia build

Some test code was doing loose conversions caught by compiler
warnings in  the Fuchsia build.  This included duplicated code
in a few tests that was reconsolidated with the existing header
file copy of the same functions.

The MemoryMatcher abstraction presumes gtest-style matcher support,
which is not available in Fuchsia's zxtest library.  It's avoided
in favor of simpler memory-comparing assertions.

Reviewed By: abrachet

Differential Revision: https://reviews.llvm.org/D146343

1 files changed, 4 insertions, 16 deletions

diff --git a/libc/test/src/string/bcopy_test.cpp b/libc/test/src/string/bcopy_test.cpp
index c1c0dae4fcd6..affd23b1bd8b 100644
--- a/libc/test/src/string/bcopy_test.cpp
+++ b/libc/test/src/string/bcopy_test.cpp
@@ -6,8 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/__support/CPP/span.h"
 #include "src/string/bcopy.h"
+
+#include "memory_utils/memory_check_utils.h"
+#include "src/__support/CPP/span.h"
 #include "test/UnitTest/MemoryMatcher.h"
 #include "test/UnitTest/Test.h"
 
@@ -70,24 +72,10 @@ TEST(LlvmLibcBcopyTest, DstFollowSrc) {
 
 static constexpr int kMaxSize = 512;
 
-char GetRandomChar() {
-  static constexpr const uint64_t A = 1103515245;
-  static constexpr const uint64_t C = 12345;
-  static constexpr const uint64_t M = 1ULL << 31;
-  static uint64_t Seed = 123456789;
-  Seed = (A * Seed + C) % M;
-  return Seed;
-}
-
-void Randomize(span<char> Buffer) {
-  for (auto &current : Buffer)
-    current = GetRandomChar();
-}
-
 TEST(LlvmLibcBcopyTest, SizeSweep) {
   using LargeBuffer = array<char, 3 * kMaxSize>;
   LargeBuffer GroundTruth;
-  Randomize(GroundTruth);
+  __llvm_libc::Randomize(GroundTruth);
   for (int Size = 0; Size < kMaxSize; ++Size) {
     for (int Offset = -Size; Offset < Size; ++Offset) {
       LargeBuffer Buffer = GroundTruth;