Fix available_chunks() for constant components (#942)

* Add (failing) test for available_chunks() on a constant record

* Fix available_chunks() for constant components

Author: franzpoeschel

src/backend/BaseRecordComponent.cpp

@@ -59,6 +59,11 @@ BaseRecordComponent::constant() const
 ChunkTable
 BaseRecordComponent::availableChunks()
 {
+    if( m_isConstant && *m_isConstant )
+    {
+        Offset offset( m_dataset->extent.size(), 0 );
+        return ChunkTable{ { std::move( offset ), m_dataset->extent } };
+    }
     Parameter< Operation::AVAILABLE_CHUNKS > param;
     IOTask task( this, param );
     IOHandler()->enqueue( task );

test/SerialIOTest.cpp

@@ -183,7 +183,12 @@ TEST_CASE( "available_chunks_test_json", "[serial][json]" )
         {
             E_x.storeChunk( data, { line, 0 }, { 1, 2 } );
         }
-        E_x.storeChunk( data, { 8, 3 }, {2, 1 } );
+        E_x.storeChunk( data, { 8, 3 }, { 2, 1 } );
+
+        auto E_y = it0.meshes[ "E" ][ "y" ];
+        E_y.resetDataset( { Datatype::INT, { height, 4 } } );
+        E_y.makeConstant( 1234 );
+
         it0.close();
     }
 
@@ -200,6 +205,12 @@ TEST_CASE( "available_chunks_test_json", "[serial][json]" )
         REQUIRE( bool( table[ 0 ] == WrittenChunkInfo( { 2, 0 }, { 5, 4 } ) ) );
         REQUIRE( bool( table[ 1 ] == WrittenChunkInfo( { 7, 0 }, { 2, 2 } ) ) );
         REQUIRE( bool( table[ 2 ] == WrittenChunkInfo( { 8, 3 }, { 2, 1 } ) ) );
+
+        auto E_y = it0.meshes[ "E" ][ "y" ];
+        table = E_y.availableChunks();
+        REQUIRE( table.size() == 1 );
+        REQUIRE(
+            bool( table[ 0 ] == WrittenChunkInfo( { 0, 0 }, { height, 4 } ) ) );
     }
 }