Add Unit tests for Arena allocator

tests/test_util.cpp

@@ -0,0 +1,49 @@
+#include "test_util.h"
+
+#include <algorithm>
+
+namespace mimir_tests {
+
+const size_t kPatternLen = 32;
+
+void getPattern(std::byte* pattern, int seed)
+{
+  for (int i = 0; i < kPatternLen; i++) {
+    pattern[i] = std::byte((seed * 3162 + i * 63163) % 0xff);
+  }
+}
+
+void writeData(std::byte* dest, size_t count, int seed)
+{
+  std::byte pattern[kPatternLen];
+  getPattern(pattern, seed);
+
+  for (int i = 0; i < count; i += kPatternLen) {
+    memcpy(dest + i, pattern, std::min(count - i, kPatternLen));
+  }
+}
+
+bool checkData(std::byte* src, size_t count, int seed)
+{
+  std::byte pattern[kPatternLen];
+  getPattern(pattern, seed);
+
+  for (int i = 0; i < count; i += kPatternLen) {
+    if (memcmp(src + i, pattern, std::min(count - i, kPatternLen)) != 0) {
+      return false;
+    }
+  }
+  return true;
+}
+
+size_t alignUp(size_t val, size_t alignment)
+{
+  return alignDown(val - 1, alignment) + alignment;
+}
+
+size_t alignDown(size_t val, size_t alignment)
+{
+  return val & ~(alignment - 1);
+}
+
+}; // namespace mimir_tests