anchor.diff:    allocate(pos1(3, N))
     allocate(pos2(3, N))
   
  -  call tester% init()
  +  call test% init()
   
     call random_seed(size = seed_size)
     allocate(seed(seed_size))
  
positive.code: 
    call solvent_cells%count_particles(pos)
  
    call tester% assert_equal(solvent_cells%cell_start(1), 1)
    call tester% assert_equal(solvent_cells%cell_start(solvent_cells%N), N+1)
    call tester% assert_equal(sum(solvent_cells%cell_count), N)
  
    h = 1
    do i = 1, N
  
negative.code:   implicit none
  
    type(cell_system_t) :: solvent_cells
    type(tester_t) :: test
  
    integer, parameter :: N = 1000000
    double precision, target, allocatable :: pos1(:, :), pos2(:, :)
  