title: NetworkX Test Failure
body: <p>I installed NetworkX via conda on pyzo4.4.1. The python version I use is 3.6.1</p>
  
  <pre><code>conda install networkx
  conda update networkx
  </code></pre>
  
  <p>As it is suggested in the installation guide of NetworkX, I also installed nose for testing and ran the full test with the following command:</p>
  
  <pre><code>import networkx as nx
  nx.test()
  </code></pre>
  
  <p>To my surprise, it yielded 57 failed tests. Here is a link to the <a href="https://justpaste.it/19poe" rel="nofollow noreferrer">complete log</a>. Here's a short summary:</p>
  
  <pre><code>Failure:
  test_kcomponents.test_example_1_detail_3_and_4
  ----------------------------------------------------------------------------
  Approximate current-flow betweenness centrality: K4
   # in total there are 9 other failed tests concerning betweenness centrality
  ----------------------------------------------------------------------------
  test_hits.TestHITS.test_hits
   # 4 of these
  ----------------------------------------------------------------------------
  test_pagerank.TestPageRank.test_dangling_pagerank
   # 12 of these
  ----------------------------------------------------------------------------
  test_branchings.test_greedy_max1
    # 4 of these
  ...
  </code></pre>
  
  <p>I tried removing the networkx and decorator and reinstalling it via conda. I then removed it yet again and installed via pip, still it does not work.
  I need some of the functions that are failing the tests (for example betweenness). Help would be greatly appreciated.</p>