diff --git a/src/test/dbwrapper_tests.cpp b/src/test/dbwrapper_tests.cpp
index c3e67a49b..e497ac3e3 100644
--- a/src/test/dbwrapper_tests.cpp
+++ b/src/test/dbwrapper_tests.cpp
@@ -1,316 +1,332 @@
 // Copyright (c) 2012-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <dbwrapper.h>
 
 #include <random.h>
 #include <uint256.h>
 
 #include <test/test_bitcoin.h>
 
 #include <boost/test/unit_test.hpp>
 
 // Test if a string consists entirely of null characters
 static bool is_null_key(const std::vector<uint8_t> &key) {
     bool isnull = true;
 
     for (unsigned int i = 0; i < key.size(); i++)
         isnull &= (key[i] == '\x00');
 
     return isnull;
 }
 
 BOOST_FIXTURE_TEST_SUITE(dbwrapper_tests, BasicTestingSetup)
 
 BOOST_AUTO_TEST_CASE(dbwrapper) {
     // Perform tests both obfuscated and non-obfuscated.
     for (bool obfuscate : {false, true}) {
         fs::path ph = SetDataDir(
             std::string("dbwrapper").append(obfuscate ? "_true" : "_false"));
         CDBWrapper dbw(ph, (1 << 20), true, false, obfuscate);
         char key = 'k';
         uint256 in = InsecureRand256();
         uint256 res;
 
         // Ensure that we're doing real obfuscation when obfuscate=true
         BOOST_CHECK(obfuscate !=
                     is_null_key(dbwrapper_private::GetObfuscateKey(dbw)));
 
         BOOST_CHECK(dbw.Write(key, in));
         BOOST_CHECK(dbw.Read(key, res));
         BOOST_CHECK_EQUAL(res.ToString(), in.ToString());
     }
 }
 
 // Test batch operations
 BOOST_AUTO_TEST_CASE(dbwrapper_batch) {
     // Perform tests both obfuscated and non-obfuscated.
     for (bool obfuscate : {false, true}) {
         fs::path ph = SetDataDir(std::string("dbwrapper_batch")
                                      .append(obfuscate ? "_true" : "_false"));
         CDBWrapper dbw(ph, (1 << 20), true, false, obfuscate);
 
         char key = 'i';
         uint256 in = InsecureRand256();
         char key2 = 'j';
         uint256 in2 = InsecureRand256();
         char key3 = 'k';
         uint256 in3 = InsecureRand256();
 
         uint256 res;
         CDBBatch batch(dbw);
 
         batch.Write(key, in);
         batch.Write(key2, in2);
         batch.Write(key3, in3);
 
         // Remove key3 before it's even been written
         batch.Erase(key3);
 
         dbw.WriteBatch(batch);
 
         BOOST_CHECK(dbw.Read(key, res));
         BOOST_CHECK_EQUAL(res.ToString(), in.ToString());
         BOOST_CHECK(dbw.Read(key2, res));
         BOOST_CHECK_EQUAL(res.ToString(), in2.ToString());
 
         // key3 should've never been written
         BOOST_CHECK(dbw.Read(key3, res) == false);
     }
 }
 
 BOOST_AUTO_TEST_CASE(dbwrapper_iterator) {
     // Perform tests both obfuscated and non-obfuscated.
     for (bool obfuscate : {false, true}) {
         fs::path ph = SetDataDir(std::string("dbwrapper_iterator")
                                      .append(obfuscate ? "_true" : "_false"));
         CDBWrapper dbw(ph, (1 << 20), true, false, obfuscate);
 
         // The two keys are intentionally chosen for ordering
         char key = 'j';
         uint256 in = InsecureRand256();
         BOOST_CHECK(dbw.Write(key, in));
         char key2 = 'k';
         uint256 in2 = InsecureRand256();
         BOOST_CHECK(dbw.Write(key2, in2));
 
         std::unique_ptr<CDBIterator> it(
             const_cast<CDBWrapper &>(dbw).NewIterator());
 
         // Be sure to seek past the obfuscation key (if it exists)
         it->Seek(key);
 
         char key_res;
         uint256 val_res;
 
         it->GetKey(key_res);
         it->GetValue(val_res);
         BOOST_CHECK_EQUAL(key_res, key);
         BOOST_CHECK_EQUAL(val_res.ToString(), in.ToString());
 
         it->Next();
 
         it->GetKey(key_res);
         it->GetValue(val_res);
         BOOST_CHECK_EQUAL(key_res, key2);
         BOOST_CHECK_EQUAL(val_res.ToString(), in2.ToString());
 
         it->Next();
         BOOST_CHECK_EQUAL(it->Valid(), false);
     }
 }
 
 // Test that we do not obfuscation if there is existing data.
 BOOST_AUTO_TEST_CASE(existing_data_no_obfuscate) {
     // We're going to share this fs::path between two wrappers
     fs::path ph = SetDataDir("existing_data_no_obfuscate");
     create_directories(ph);
 
     // Set up a non-obfuscated wrapper to write some initial data.
     std::unique_ptr<CDBWrapper> dbw =
         std::make_unique<CDBWrapper>(ph, (1 << 10), false, false, false);
     char key = 'k';
     uint256 in = InsecureRand256();
     uint256 res;
 
     BOOST_CHECK(dbw->Write(key, in));
     BOOST_CHECK(dbw->Read(key, res));
     BOOST_CHECK_EQUAL(res.ToString(), in.ToString());
 
     // Call the destructor to free leveldb LOCK
     dbw.reset();
 
     // Now, set up another wrapper that wants to obfuscate the same directory
     CDBWrapper odbw(ph, (1 << 10), false, false, true);
 
     // Check that the key/val we wrote with unobfuscated wrapper exists and
     // is readable.
     uint256 res2;
     BOOST_CHECK(odbw.Read(key, res2));
     BOOST_CHECK_EQUAL(res2.ToString(), in.ToString());
 
     // There should be existing data
     BOOST_CHECK(!odbw.IsEmpty());
     // The key should be an empty string
     BOOST_CHECK(is_null_key(dbwrapper_private::GetObfuscateKey(odbw)));
 
     uint256 in2 = InsecureRand256();
     uint256 res3;
 
     // Check that we can write successfully
     BOOST_CHECK(odbw.Write(key, in2));
     BOOST_CHECK(odbw.Read(key, res3));
     BOOST_CHECK_EQUAL(res3.ToString(), in2.ToString());
 }
 
 // Ensure that we start obfuscating during a reindex.
 BOOST_AUTO_TEST_CASE(existing_data_reindex) {
     // We're going to share this fs::path between two wrappers
     fs::path ph = SetDataDir("existing_data_reindex");
     create_directories(ph);
 
     // Set up a non-obfuscated wrapper to write some initial data.
     std::unique_ptr<CDBWrapper> dbw =
         std::make_unique<CDBWrapper>(ph, (1 << 10), false, false, false);
     char key = 'k';
     uint256 in = InsecureRand256();
     uint256 res;
 
     BOOST_CHECK(dbw->Write(key, in));
     BOOST_CHECK(dbw->Read(key, res));
     BOOST_CHECK_EQUAL(res.ToString(), in.ToString());
 
     // Call the destructor to free leveldb LOCK
     dbw.reset();
 
     // Simulate a -reindex by wiping the existing data store
     CDBWrapper odbw(ph, (1 << 10), false, true, true);
 
     // Check that the key/val we wrote with unobfuscated wrapper doesn't exist
     uint256 res2;
     BOOST_CHECK(!odbw.Read(key, res2));
     BOOST_CHECK(!is_null_key(dbwrapper_private::GetObfuscateKey(odbw)));
 
     uint256 in2 = InsecureRand256();
     uint256 res3;
 
     // Check that we can write successfully
     BOOST_CHECK(odbw.Write(key, in2));
     BOOST_CHECK(odbw.Read(key, res3));
     BOOST_CHECK_EQUAL(res3.ToString(), in2.ToString());
 }
 
 BOOST_AUTO_TEST_CASE(iterator_ordering) {
     fs::path ph = SetDataDir("iterator_ordering");
     CDBWrapper dbw(ph, (1 << 20), true, false, false);
     for (int x = 0x00; x < 256; ++x) {
         uint8_t key = x;
         uint32_t value = x * x;
-        BOOST_CHECK(dbw.Write(key, value));
+        if (!(x & 1)) {
+            BOOST_CHECK(dbw.Write(key, value));
+        }
     }
 
+    // Check that creating an iterator creates a snapshot
     std::unique_ptr<CDBIterator> it(
         const_cast<CDBWrapper &>(dbw).NewIterator());
+
+    for (int x = 0x00; x < 256; ++x) {
+        uint8_t key = x;
+        uint32_t value = x * x;
+        if (x & 1) {
+            BOOST_CHECK(dbw.Write(key, value));
+        }
+    }
+
     for (int seek_start : {0x00, 0x80}) {
         it->Seek((uint8_t)seek_start);
-        for (int x = seek_start; x < 256; ++x) {
+        for (int x = seek_start; x < 255; ++x) {
             uint8_t key;
             uint32_t value;
             BOOST_CHECK(it->Valid());
             // Avoid spurious errors about invalid iterator's  key and value in
             // case of failure
             if (!it->Valid()) break;
             BOOST_CHECK(it->GetKey(key));
+            if (x & 1) {
+                BOOST_CHECK_EQUAL(key, x + 1);
+                continue;
+            }
             BOOST_CHECK(it->GetValue(value));
             BOOST_CHECK_EQUAL(key, x);
             BOOST_CHECK_EQUAL(value, x * x);
             it->Next();
         }
         BOOST_CHECK(!it->Valid());
     }
 }
 
 struct StringContentsSerializer {
     // Used to make two serialized objects the same while letting them have a
     // different lengths. This is a terrible idea.
     std::string str;
     StringContentsSerializer() {}
     explicit StringContentsSerializer(const std::string &inp) : str(inp) {}
 
     StringContentsSerializer &operator+=(const std::string &s) {
         str += s;
         return *this;
     }
     StringContentsSerializer &operator+=(const StringContentsSerializer &s) {
         return *this += s.str;
     }
 
     ADD_SERIALIZE_METHODS;
 
     template <typename Stream, typename Operation>
     inline void SerializationOp(Stream &s, Operation ser_action) {
         if (ser_action.ForRead()) {
             str.clear();
             char c = 0;
             while (true) {
                 try {
                     READWRITE(c);
                     str.push_back(c);
                 } catch (const std::ios_base::failure &e) {
                     break;
                 }
             }
         } else {
             for (size_t i = 0; i < str.size(); i++)
                 READWRITE(str[i]);
         }
     }
 };
 
 BOOST_AUTO_TEST_CASE(iterator_string_ordering) {
     char buf[10];
 
     fs::path ph = SetDataDir("iterator_string_ordering");
     CDBWrapper dbw(ph, (1 << 20), true, false, false);
     for (int x = 0x00; x < 10; ++x) {
         for (int y = 0; y < 10; y++) {
             snprintf(buf, sizeof(buf), "%d", x);
             StringContentsSerializer key(buf);
             for (int z = 0; z < y; z++)
                 key += key;
             uint32_t value = x * x;
             BOOST_CHECK(dbw.Write(key, value));
         }
     }
 
     std::unique_ptr<CDBIterator> it(
         const_cast<CDBWrapper &>(dbw).NewIterator());
     for (int seek_start : {0, 5}) {
         snprintf(buf, sizeof(buf), "%d", seek_start);
         StringContentsSerializer seek_key(buf);
         it->Seek(seek_key);
         for (int x = seek_start; x < 10; ++x) {
             for (int y = 0; y < 10; y++) {
                 snprintf(buf, sizeof(buf), "%d", x);
                 std::string exp_key(buf);
                 for (int z = 0; z < y; z++)
                     exp_key += exp_key;
                 StringContentsSerializer key;
                 uint32_t value;
                 BOOST_CHECK(it->Valid());
                 // Avoid spurious errors about invalid iterator's key and value
                 // in case of failure
                 if (!it->Valid()) break;
                 BOOST_CHECK(it->GetKey(key));
                 BOOST_CHECK(it->GetValue(value));
                 BOOST_CHECK_EQUAL(key.str, exp_key);
                 BOOST_CHECK_EQUAL(value, x * x);
                 it->Next();
             }
         }
         BOOST_CHECK(!it->Valid());
     }
 }
 
 BOOST_AUTO_TEST_SUITE_END()