Draw num writes directly

Internal.h

@@ -474,11 +474,13 @@ template <class ConflictSetImpl> struct TestDriver {
     }
     Arena arena;
     {
-      int numWriteKeys = arbitrary.bounded(10);
+      int numPointWrites = arbitrary.bounded(100);
+      int numRangeWrites = arbitrary.bounded(100);
       int64_t v = ++writeVersion;
-      auto *writes = new (arena) ConflictSet::WriteRange[numWriteKeys];
+      auto *writes =
+          new (arena) ConflictSet::WriteRange[numPointWrites + numRangeWrites];
       auto keys = set<std::string_view>(arena);
-      while (int(keys.size()) < numWriteKeys) {
+      while (int(keys.size()) < numPointWrites + numRangeWrites * 2) {
         if (!arbitrary.hasEntropy()) {
           return true;
         }
@@ -487,37 +489,51 @@ template <class ConflictSetImpl> struct TestDriver {
         arbitrary.randomBytes(begin, keyLen);
         keys.insert(std::string_view((const char *)begin, keyLen));
       }
+
       auto iter = keys.begin();
-      int numWrites = 0;
-      for (int i = 0; i < numWriteKeys; ++i, ++numWrites) {
-        writes[numWrites].begin.p = (const uint8_t *)iter->data();
-        writes[numWrites].begin.len = iter->size();
-        ++iter;
-        if (i + 1 < numWriteKeys && arbitrary.bounded(2)) {
-          ++i;
-          writes[numWrites].end.p = (const uint8_t *)iter->data();
-          writes[numWrites].end.len = iter->size();
+      int i = 0;
+      for (int pointsRemaining = numPointWrites,
+               rangesRemaining = numRangeWrites;
+           pointsRemaining > 0 || rangesRemaining > 0; ++i) {
+        bool pointRead = pointsRemaining > 0 && rangesRemaining > 0
+                             ? bool(arbitrary.bounded(2))
+                             : pointsRemaining > 0;
+        if (pointRead) {
+          assert(pointsRemaining > 0);
+          writes[i].begin.p = (const uint8_t *)iter->data();
+          writes[i].begin.len = iter->size();
+          writes[i].end.len = 0;
           ++iter;
+          --pointsRemaining;
         } else {
-          writes[numWrites].end.len = 0;
+          assert(rangesRemaining > 0);
+          writes[i].begin.p = (const uint8_t *)iter->data();
+          writes[i].begin.len = iter->size();
+          ++iter;
+          writes[i].end.p = (const uint8_t *)iter->data();
+          writes[i].end.len = iter->size();
+          ++iter;
+          --rangesRemaining;
         }
-        writes[numWrites].writeVersion = v;
+        writes[i].writeVersion = v;
 #if DEBUG_VERBOSE && !defined(NDEBUG)
-        if (writes[numWrites].end.len == 0) {
+        if (writes[i].end.len == 0) {
           fprintf(stderr, "Write: {%s} -> %d\n",
-                  printable(writes[numWrites].begin).c_str(),
-                  int(writes[numWrites].writeVersion));
+                  printable(writes[i].begin).c_str(),
+                  int(writes[i].writeVersion));
         } else {
           fprintf(stderr, "Write: [%s, %s) -> %d\n",
-                  printable(writes[numWrites].begin).c_str(),
-                  printable(writes[numWrites].end).c_str(),
-                  int(writes[numWrites].writeVersion));
+                  printable(writes[i].begin).c_str(),
+                  printable(writes[i].end).c_str(),
+                  int(writes[i].writeVersion));
         }
 #endif
       }
       assert(iter == keys.end());
-      cs.addWrites(writes, numWrites);
-      refImpl.addWrites(writes, numWrites);
+      assert(i == numPointWrites + numRangeWrites);
+
+      cs.addWrites(writes, numPointWrites + numRangeWrites);
+      refImpl.addWrites(writes, numPointWrites + numRangeWrites);
     }
     {
       int numReads = arbitrary.bounded(10);