No vertices:
Incidence matrix:
Row ids:
( )
Col ids:
( )

One vertex:
Incidence matrix:
Row ids:
( )
Col ids:
( 0 )

Disconnected graph with multiple edges:
Incidence matrix:
[        1        3        0
         1        1        2
         0        0        0 ]
Row ids:
( 0 3 5 )
Col ids:
( 1 2 4 )

Checking non-bipartite graph.
Incidence matrix:
[        1        3        0
         1        1        2
         0        0        0 ]
Row ids:
( 0 3 5 )
Col ids:
( 1 2 4 )

Checking wrong type vector size error handling.