Refactor leveldbwrapper

Was "Add chainstate obfuscation to avoid spurious antivirus detection"

Zcash: Extracted the refactor, omitting the chainstate obfuscation.

src/test/leveldbwrapper_tests.cpp

@@ -0,0 +1,45 @@
+// Copyright (c) 2012-2013 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 "leveldbwrapper.h"
+#include "uint256.h"
+#include "random.h"
+#include "test/test_bitcoin.h"
+
+#include <boost/assign/std/vector.hpp> // for 'operator+=()'
+#include <boost/assert.hpp>
+#include <boost/test/unit_test.hpp>
+                    
+using namespace std;
+using namespace boost::assign; // bring 'operator+=()' into scope
+using namespace boost::filesystem;
+         
+// Test if a string consists entirely of null characters
+bool is_null_key(const vector<unsigned char>& key) {
+    bool isnull = true;
+
+    for (unsigned int i = 0; i < key.size(); i++)
+        isnull &= (key[i] == '\x00');
+
+    return isnull;
+}
+ 
+BOOST_FIXTURE_TEST_SUITE(leveldbwrapper_tests, BasicTestingSetup)
+                       
+BOOST_AUTO_TEST_CASE(leveldbwrapper)
+{
+    {
+        path ph = temp_directory_path() / unique_path();
+        CLevelDBWrapper dbw(ph, (1 << 20), true, false);
+        char key = 'k';
+        uint256 in = GetRandHash();
+        uint256 res;
+
+        BOOST_CHECK(dbw.Write(key, in));
+        BOOST_CHECK(dbw.Read(key, res));
+        BOOST_CHECK_EQUAL(res.ToString(), in.ToString());
+    }
+}
+ 
+BOOST_AUTO_TEST_SUITE_END()