Implement setOldestVersion

Internal.h

@@ -470,14 +470,14 @@ inline std::string printable(std::span<const uint8_t> key) {
 namespace {
 
 template <class ConflictSetImpl> struct TestDriver {
-  // TODO call setOldestVersion
   Arbitrary arbitrary;
   explicit TestDriver(const uint8_t *data, size_t size)
       : arbitrary({data, size}) {}
 
   int64_t writeVersion = 0;
-  ConflictSetImpl cs{writeVersion};
-  ReferenceImpl refImpl{writeVersion};
+  int64_t oldestVersion = 0;
+  ConflictSetImpl cs{oldestVersion};
+  ReferenceImpl refImpl{oldestVersion};
 
   constexpr static auto kMaxKeyLen = 32;
 
@@ -659,6 +659,9 @@ template <class ConflictSetImpl> struct TestDriver {
         }
       }
     }
+    oldestVersion += arbitrary.bounded(2);
+    cs.setOldestVersion(oldestVersion);
+    refImpl.setOldestVersion(oldestVersion);
     return false;
   }
 };