old_contents: import numpy as np
  import numpy.testing as npt
  import sys
  
  sys.path.append('..')
  
  import pcst_fast
  
  def test_simple1():
    edges = [[0, 1], [1, 2], [2, 3]]
    prizes = [1.0, 1.0, 1.0, 1.0]
    costs = [0.8, 1.8, 2.8]
    result_nodes, result_edges = pcst_fast.pcst_fast(edges, prizes, costs, -1, 1, 'strong', 0)
    npt.assert_array_equal(result_nodes, [0, 1])
    npt.assert_array_equal(result_edges, [0])
  
  def test_simple2():
    edges = [[0, 1], [1, 2]]
    prizes = [0.0, 5.0, 6.0]
    costs = [3.0, 4.0]
    result_nodes, result_edges = pcst_fast.pcst_fast(edges, prizes, costs, 0, 1, 'none', 0)
    npt.assert_array_equal(sorted(result_nodes), [0, 1, 2])
    npt.assert_array_equal(sorted(result_edges), [0, 1])
  
new_contents: import numpy as np
  import numpy.testing as npt
  import sys
  
  sys.path.append('..')
  
  import pcst_fast
  
  def test_simple1():
    edges = [[0, 1], [1, 2], [2, 3]]
    prizes = [1.0, 1.0, 1.0, 1.0]
    costs = [0.8, 1.8, 2.8]
    result_nodes, result_edges = pcst_fast.pcst_fast(edges, prizes, costs, -1, 1, 'strong', 0)
    npt.assert_array_equal(result_nodes, [0, 1])
    npt.assert_array_equal(result_edges, [0])
  
  def test_simple2():
    edges = [[0, 1], [1, 2]]
    prizes = [0.0, 5.0, 6.0]
    costs = [3.0, 4.0]
    result_nodes, result_edges = pcst_fast.pcst_fast(edges, prizes, costs, 0, 1, 'none', 0)
    npt.assert_array_equal(sorted(result_nodes), [0, 1, 2])
    npt.assert_array_equal(sorted(result_edges), [0, 1])
  
  
  def test_num_clusters():
    """
    create a graph as follows:
    0---1---2---3
        |   |   |
        4   5   6
    """
    edges = [[0, 1], [1, 2], [1, 4],[2, 3], [2, 5], [3,6]]
    prizes = [100., 0., 0., 0., 100., 100., 100.]
    costs = [10., 100., 10., 10., 10., 10.]
    result_nodes, result_edges = pcst_fast.pcst_fast(edges, prizes, costs, -1, 2, 'strong' , 0)
    npt.assert_array_equal(sorted(result_nodes), [0, 1, 2, 3, 4, 5, 6])
    npt.assert_array_equal(sorted(result_edges), [0, 2, 3, 4, 5])
  
subject: add test to check num_clusters functionality