diff --git a/unittests/DebugInfo/PDB/PDBApiTest.cpp b/unittests/DebugInfo/PDB/PDBApiTest.cpp
index fd65d10dfed..1917097c783 100644
--- a/unittests/DebugInfo/PDB/PDBApiTest.cpp
+++ b/unittests/DebugInfo/PDB/PDBApiTest.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <memory>
 #include <unordered_map>
 
 #include "llvm/DebugInfo/PDB/IPDBEnumChildren.h"
@@ -78,6 +79,10 @@ class MockSession : public IPDBSession {
       const PDBSymbolCompiland &Compiland) const override {
     return nullptr;
   }
+
+  std::unique_ptr<IPDBEnumDataStreams> getDebugStreams() const override {
+    return nullptr;
+  }
 };
 
 class MockRawSymbol : public IPDBRawSymbol {