diff --git a/dbms/src/DataStreams/tests/aggregating_stream.cpp b/dbms/src/DataStreams/tests/aggregating_stream.cpp
index 4e29b32eb69..4fa85c09018 100644
--- a/dbms/src/DataStreams/tests/aggregating_stream.cpp
+++ b/dbms/src/DataStreams/tests/aggregating_stream.cpp
@@ -17,36 +17,12 @@
 #include <DB/DataStreams/AggregatingBlockInputStream.h>
 #include <DB/DataStreams/FinalizingAggregatedBlockInputStream.h>
 #include <DB/DataStreams/TabSeparatedRowOutputStream.h>
+#include <DB/DataStreams/OneBlockInputStream.h>
 #include <DB/DataStreams/copyData.h>
 
 #include <DB/AggregateFunctions/AggregateFunctionFactory.h>
 
 
-class OneBlockInputStream : public DB::IBlockInputStream
-{
-private:
-	const DB::Block & block;
-	bool has_been_read;
-public:
-	OneBlockInputStream(const DB::Block & block_) : block(block_), has_been_read(false) {}
-
-	DB::Block read()
-	{
-		if (!has_been_read)
-		{
-			has_been_read = true;
-			return block;
-		}
-		else
-			return DB::Block();
-	}
-
-	DB::String getName() const { return "OneBlockInputStream"; }
-
-	DB::BlockInputStreamPtr clone() { return new OneBlockInputStream(block); }
-};
-
-
 int main(int argc, char ** argv)
 {
 	try
@@ -116,7 +92,7 @@ int main(int argc, char ** argv)
 			sample.insert(col);
 		}
 
-		DB::BlockInputStreamPtr stream = new OneBlockInputStream(block);
+		DB::BlockInputStreamPtr stream = new DB::OneBlockInputStream(block);
 		stream = new DB::AggregatingBlockInputStream(stream, key_column_numbers, aggregate_descriptions, 0, DB::Limits::THROW);
 		stream = new DB::FinalizingAggregatedBlockInputStream(stream);
 
diff --git a/dbms/src/Interpreters/tests/aggregate.cpp b/dbms/src/Interpreters/tests/aggregate.cpp
index 564c5ec4f23..11d2dbb59b2 100644
--- a/dbms/src/Interpreters/tests/aggregate.cpp
+++ b/dbms/src/Interpreters/tests/aggregate.cpp
@@ -9,38 +9,13 @@
 #include <DB/Columns/ColumnsNumber.h>
 #include <DB/Columns/ColumnString.h>
 
-#include <DB/DataStreams/IBlockInputStream.h>
+#include <DB/DataStreams/OneBlockInputStream.h>
 
 #include <DB/Interpreters/Aggregator.h>
 
 #include <DB/AggregateFunctions/AggregateFunctionFactory.h>
 
 
-class OneBlockInputStream : public DB::IBlockInputStream
-{
-private:
-	const DB::Block & block;
-	bool has_been_read;
-public:
-	OneBlockInputStream(const DB::Block & block_) : block(block_), has_been_read(false) {}
-
-	DB::Block read()
-	{
-		if (!has_been_read)
-		{
-			has_been_read = true;
-			return block;
-		}
-		else
-			return DB::Block();
-	}
-
-	DB::String getName() const { return "OneBlockInputStream"; }
-
-	DB::BlockInputStreamPtr clone() { return new OneBlockInputStream(block); }
-};
-
-
 int main(int argc, char ** argv)
 {
 	try
@@ -84,7 +59,7 @@ int main(int argc, char ** argv)
 
 		block.insert(column_s2);
 
-		DB::BlockInputStreamPtr stream = new OneBlockInputStream(block);
+		DB::BlockInputStreamPtr stream = new DB::OneBlockInputStream(block);
 		DB::AggregatedDataVariants aggregated_data_variants;
 
 		DB::ColumnNumbers key_column_numbers;
diff --git a/dbms/src/Interpreters/tests/expression.cpp b/dbms/src/Interpreters/tests/expression.cpp
index ee313902369..12ec30f15e6 100644
--- a/dbms/src/Interpreters/tests/expression.cpp
+++ b/dbms/src/Interpreters/tests/expression.cpp
@@ -16,6 +16,7 @@
 
 #include <DB/DataStreams/TabSeparatedRowOutputStream.h>
 #include <DB/DataStreams/LimitBlockInputStream.h>
+#include <DB/DataStreams/OneBlockInputStream.h>
 #include <DB/DataStreams/copyData.h>
 
 #include <DB/Interpreters/Expression.h>
@@ -46,31 +47,6 @@ void dump(DB::IAST & ast, int level = 0)
 }
 
 
-class OneBlockInputStream : public DB::IBlockInputStream
-{
-private:
-	const DB::Block & block;
-	bool has_been_read;
-public:
-	OneBlockInputStream(const DB::Block & block_) : block(block_), has_been_read(false) {}
-
-	DB::Block read()
-	{
-		if (!has_been_read)
-		{
-			has_been_read = true;
-			return block;
-		}
-		else
-			return DB::Block();
-	}
-
-	DB::String getName() const { return "OneBlockInputStream"; }
-
-	DB::BlockInputStreamPtr clone() { return new OneBlockInputStream(block); }
-};
-
-
 int main(int argc, char ** argv)
 {
 	try
@@ -168,7 +144,7 @@ int main(int argc, char ** argv)
 				<< std::endl;
 		}
 		
-		OneBlockInputStream * is = new OneBlockInputStream(block);
+		DB::OneBlockInputStream * is = new DB::OneBlockInputStream(block);
 		DB::LimitBlockInputStream lis(is, 20, std::max(0, static_cast<int>(n) - 20));
 		DB::WriteBufferFromOStream out_buf(std::cout);
 		DB::TabSeparatedRowOutputStream os(out_buf, block);