diff --git a/src/test/blobstore/implementations/onblocks/impl/DataLeafNodeTest.cpp b/src/test/blobstore/implementations/onblocks/impl/DataLeafNodeTest.cpp
index 4fcc9316..b272dc6a 100644
--- a/src/test/blobstore/implementations/onblocks/impl/DataLeafNodeTest.cpp
+++ b/src/test/blobstore/implementations/onblocks/impl/DataLeafNodeTest.cpp
@@ -1,7 +1,7 @@
 #include <gtest/gtest.h>
 
-#include "blockstore/implementations/inmemory/InMemoryBlockStore.h"
-#include "blockstore/implementations/inmemory/InMemoryBlock.h"
+#include "blockstore/implementations/testfake/FakeBlockStore.h"
+#include "blockstore/implementations/testfake/FakeBlock.h"
 #include "blobstore/implementations/onblocks/BlobStoreOnBlocks.h"
 #include "blobstore/implementations/onblocks/impl/DataLeafNode.h"
 #include "test/testutils/DataBlockFixture.h"
@@ -16,7 +16,7 @@ using std::string;
 using blockstore::BlockStore;
 using blockstore::BlockWithKey;
 using blockstore::Data;
-using blockstore::inmemory::InMemoryBlockStore;
+using blockstore::testfake::FakeBlockStore;
 using namespace blobstore;
 using namespace blobstore::onblocks;
 
@@ -28,7 +28,7 @@ public:
   DataLeafNodeTest():
     ZEROES(DataLeafNode::MAX_STORED_BYTES),
     randomData(DataLeafNode::MAX_STORED_BYTES),
-    blockStore(make_unique<InMemoryBlockStore>()),
+    blockStore(make_unique<FakeBlockStore>()),
     block(blockStore->create(DataNodeView::BLOCKSIZE_BYTES)),
     leafblock(blockStore->create(DataNodeView::BLOCKSIZE_BYTES)),
     leafblockdata((uint8_t*)leafblock.block->data()),
diff --git a/src/test/blobstore/implementations/onblocks/impl/DataNodeTest.cpp b/src/test/blobstore/implementations/onblocks/impl/DataNodeTest.cpp
index c339b504..6ffcaffc 100644
--- a/src/test/blobstore/implementations/onblocks/impl/DataNodeTest.cpp
+++ b/src/test/blobstore/implementations/onblocks/impl/DataNodeTest.cpp
@@ -1,7 +1,7 @@
 #include <gtest/gtest.h>
 
-#include "blockstore/implementations/inmemory/InMemoryBlockStore.h"
-#include "blockstore/implementations/inmemory/InMemoryBlock.h"
+#include "blockstore/implementations/testfake/FakeBlockStore.h"
+#include "blockstore/implementations/testfake/FakeBlock.h"
 #include "blobstore/implementations/onblocks/BlobStoreOnBlocks.h"
 #include "blobstore/implementations/onblocks/impl/DataNode.h"
 #include "blobstore/implementations/onblocks/impl/DataLeafNode.h"
@@ -13,13 +13,13 @@ using std::make_unique;
 using std::string;
 
 using blockstore::BlockStore;
-using blockstore::inmemory::InMemoryBlockStore;
+using blockstore::testfake::FakeBlockStore;
 using namespace blobstore;
 using namespace blobstore::onblocks;
 
 class DataNodeTest: public Test {
 public:
-  unique_ptr<BlockStore> blockStore = make_unique<InMemoryBlockStore>();
+  unique_ptr<BlockStore> blockStore = make_unique<FakeBlockStore>();
 };
 
 #define EXPECT_IS_PTR_TYPE(Type, ptr) EXPECT_NE(nullptr, dynamic_cast<Type*>(ptr)) << "Given pointer cannot be cast to the given type"
diff --git a/src/test/blobstore/implementations/onblocks/impl/DataNodeViewTest.cpp b/src/test/blobstore/implementations/onblocks/impl/DataNodeViewTest.cpp
index 78099121..7107ba34 100644
--- a/src/test/blobstore/implementations/onblocks/impl/DataNodeViewTest.cpp
+++ b/src/test/blobstore/implementations/onblocks/impl/DataNodeViewTest.cpp
@@ -1,7 +1,7 @@
 #include <gtest/gtest.h>
 
-#include "blockstore/implementations/inmemory/InMemoryBlockStore.h"
-#include "blockstore/implementations/inmemory/InMemoryBlock.h"
+#include "blockstore/implementations/testfake/FakeBlockStore.h"
+#include "blockstore/implementations/testfake/FakeBlock.h"
 #include "blobstore/implementations/onblocks/BlobStoreOnBlocks.h"
 #include "blobstore/implementations/onblocks/impl/DataNodeView.h"
 #include "test/testutils/DataBlockFixture.h"
@@ -14,7 +14,7 @@ using std::make_unique;
 using std::string;
 
 using blockstore::BlockStore;
-using blockstore::inmemory::InMemoryBlockStore;
+using blockstore::testfake::FakeBlockStore;
 using namespace blobstore;
 using namespace blobstore::onblocks;
 
@@ -25,7 +25,7 @@ public:
   //     because the next block load will just give you the same data region (and the overflow data will most
   //     likely still be intact).
   //     So better write a FakeBlockStore class for test cases.
-  unique_ptr<BlockStore> blockStore = make_unique<InMemoryBlockStore>();
+  unique_ptr<BlockStore> blockStore = make_unique<FakeBlockStore>();
 };
 
 TEST_F(DataNodeViewTest, MagicNumberIsStored) {
@@ -54,13 +54,13 @@ TEST_P(DataNodeViewSizeTest, SizeIsStored) {
 
 TEST_F(DataNodeViewTest, DataIsStored) {
   DataBlockFixture randomData(DataNodeView::DATASIZE_BYTES);
-  auto block = blockStore->create(BlobStoreOnBlocks::BLOCKSIZE);
+  auto block = blockStore->create(DataNodeView::BLOCKSIZE_BYTES);
   {
     DataNodeView view(std::move(block.block));
-    std::memcpy(view.DataBegin<uint8_t>(), randomData.data(), DataNodeView::DATASIZE_BYTES);
+    std::memcpy(view.DataBegin<uint8_t>(), randomData.data(), randomData.size());
   }
   DataNodeView view(blockStore->load(block.key));
-  EXPECT_EQ(0, std::memcmp(view.DataBegin<uint8_t>(), randomData.data(), DataNodeView::DATASIZE_BYTES));
+  EXPECT_EQ(0, std::memcmp(view.DataBegin<uint8_t>(), randomData.data(), randomData.size()));
 }
 
 TEST_F(DataNodeViewTest, HeaderAndBodyDontOverlap) {
diff --git a/src/test/testutils/DataBlockFixture.cpp b/src/test/testutils/DataBlockFixture.cpp
index b4413121..ec50b91c 100644
--- a/src/test/testutils/DataBlockFixture.cpp
+++ b/src/test/testutils/DataBlockFixture.cpp
@@ -20,6 +20,12 @@ void DataBlockFixture::fillFileWithRandomData(long long int IV) {
     val += 1442695040888963407;
     reinterpret_cast<long long int*>(_fileData)[i] = val;
   }
+  //Fill remaining bytes
+  for(size_t i=(_size/sizeof(long long int))*sizeof(long long int); i<_size; ++i) {
+    val *= 6364136223846793005L;
+    val += 1442695040888963407;
+    reinterpret_cast<char*>(_fileData)[i] = val;
+  }
 }
 
 const char *DataBlockFixture::data() const {