diff --git a/llvm/unittests/DebugInfo/PDB/MappedBlockStreamTest.cpp b/llvm/unittests/DebugInfo/PDB/MappedBlockStreamTest.cpp
index 42f38a2..abeb421 100644
--- a/llvm/unittests/DebugInfo/PDB/MappedBlockStreamTest.cpp
+++ b/llvm/unittests/DebugInfo/PDB/MappedBlockStreamTest.cpp
@@ -42,16 +42,16 @@
 
   Error readBytes(uint32_t Offset, uint32_t Size,
                   ArrayRef<uint8_t> &Buffer) override {
-    if (Offset + Size > Data.size())
-      return make_error<MSFError>(msf_error_code::insufficient_buffer);
+    if (auto EC = checkOffset(Offset, Size))
+      return EC;
     Buffer = Data.slice(Offset, Size);
     return Error::success();
   }
 
   Error readLongestContiguousChunk(uint32_t Offset,
                                    ArrayRef<uint8_t> &Buffer) override {
-    if (Offset >= Data.size())
-      return make_error<MSFError>(msf_error_code::insufficient_buffer);
+    if (auto EC = checkOffset(Offset, 1))
+      return EC;
     Buffer = Data.drop_front(Offset);
     return Error::success();
   }
@@ -59,8 +59,8 @@
   uint32_t getLength() override { return Data.size(); }
 
   Error writeBytes(uint32_t Offset, ArrayRef<uint8_t> SrcData) override {
-    if (Offset + SrcData.size() > Data.size())
-      return make_error<MSFError>(msf_error_code::insufficient_buffer);
+    if (auto EC = checkOffset(Offset, SrcData.size()))
+      return EC;
     ::memcpy(&Data[Offset], SrcData.data(), SrcData.size());
     return Error::success();
   }