permute_pair_list: default to inplace=False

Closes #28

Adds test for permute_pair_list.
Fixes unrelated filename typo.

Author: zietzm

hetio/permute.py

@@ -80,7 +80,8 @@ def permute_graph(graph, multiplier=10, seed=0, metaedge_to_excluded=dict(), log
     return permuted_graph, all_stats
 
 
-def permute_pair_list(pair_list, directed=False, multiplier=10, excluded_pair_set=set(), seed=0, log=False):
+def permute_pair_list(pair_list, directed=False, multiplier=10, excluded_pair_set=set(),
+                      seed=0, log=False, inplace=False):
     """
     Permute edges (of a single type) in a graph according to the XSwap function
     described in https://doi.org/f3mn58. This method selects two edges and
@@ -116,6 +117,8 @@ def permute_pair_list(pair_list, directed=False, multiplier=10, excluded_pair_se
         Seed to initialize Python random number generator.
     log : bool
         Whether to log diagnostic INFO via python's logging module.
+    inplace : bool
+        Whether to modify the edge list in place.
 
     Returns
     -------
@@ -128,6 +131,9 @@ def permute_pair_list(pair_list, directed=False, multiplier=10, excluded_pair_se
     """
     random.seed(seed)
 
+    if not inplace:
+        pair_list = pair_list.copy()
+
     pair_set = set(pair_list)
     assert len(pair_set) == len(pair_list)
 

test/matrtix_test.py test/matrix_test.py

@@ -0,0 +1,18 @@
+import pytest
+
+import hetio.permute
+
+
+@pytest.mark.parametrize('edges,inplace', [
+    ([(0, 0), (1, 1), (1, 2), (2, 3)], True),
+    ([(0, 0), (1, 1), (1, 2), (2, 3)], False),
+])
+def test_permute_inplace(edges, inplace):
+    old_edges = edges.copy()
+    new_edges, stats = hetio.permute.permute_pair_list(edges, inplace=inplace)
+    assert old_edges != new_edges
+
+    if inplace:
+        assert edges == new_edges
+    else:
+        assert edges != new_edges