diff --git a/.travis.yml b/.travis.yml
index c180160..6557f33 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,11 +7,12 @@ addons:
   apt:
     packages:
       - libgd2-noxpm-dev
+      - libleveldb-dev
 
 before_script:
   - mkdir build
   - cd build
-  - cmake ..
+  - cmake .. -DENABLE_LEVELDB=true
 
 script: 
   - cmake --build . --config Release
diff --git a/Minetestmapper/db-leveldb.cpp b/Minetestmapper/db-leveldb.cpp
index ce80781..8dced23 100644
--- a/Minetestmapper/db-leveldb.cpp
+++ b/Minetestmapper/db-leveldb.cpp
@@ -5,7 +5,6 @@
 #include "db-leveldb.h"
 #include <stdexcept>
 #include <sstream>
-#include "types.h"
 
 inline int64_t stoi64(const std::string &s) {
 	std::stringstream tmp(s);
@@ -66,7 +65,7 @@ const DB::BlockPosList &DBLevelDB::getBlockPosList() {
 	return m_blockPosList;
 }
 
-DB::Block DBLevelDB::getBlockOnPos(const BlockPos &pos)
+const DB::Block DBLevelDB::getBlockOnPos(const BlockPos &pos)
 {
 	std::string datastr;
 	leveldb::Status status;
@@ -109,10 +108,10 @@ DB::Block DBLevelDB::getBlockOnPos(const BlockPos &pos)
 
 	if(status.ok()) {
 		m_blocksReadCount++;
-		return Block(pos, ustring(reinterpret_cast<const unsigned char *>(datastr.c_str()), datastr.size()));
+		return Block(pos, reinterpret_cast<const unsigned char *>(datastr.c_str()), datastr.size());
 	}
 	else {
-		return Block(pos, ustring(reinterpret_cast<const unsigned char *>("")));
+		return Block(pos, {});
 	}
 
 }
diff --git a/Minetestmapper/db-leveldb.h b/Minetestmapper/db-leveldb.h
index e5a766b..ea6363c 100644
--- a/Minetestmapper/db-leveldb.h
+++ b/Minetestmapper/db-leveldb.h
@@ -12,7 +12,7 @@ public:
 	virtual int getBlocksQueriedCount(void);
 	virtual int getBlocksReadCount(void);
 	virtual const BlockPosList &getBlockPosList();
-	virtual Block getBlockOnPos(const BlockPos &pos);
+	virtual const Block getBlockOnPos(const BlockPos &pos);
 	~DBLevelDB();
 private:
 	int m_blocksReadCount;