Rewrote core.util.partition, added tests for it.

i3pystatus/core/util.py

@@ -1,5 +1,6 @@
 
 import collections
+import itertools
 
 from .exceptions import *
 from .imputil import ClassFinder
@@ -21,14 +22,18 @@ def popwhile(predicate, iterable):
         else:
             break
 
-def partition(iterable, limit, key=None):
-    key = key or (lambda x: x)
-    partitions = []
-    while iterable:
+def partition(iterable, limit, key=lambda x: x):
+    def pop_partition():
         sum = 0.0
-        partitions.append(list(
-            popwhile(lambda x: sum + key(x) or sum < limit, iterable)
-        ))
+        while sum < limit and iterable:
+            sum += key(iterable[-1])
+            yield iterable.pop()
+
+    partitions = []
+    iterable.sort(reverse=True)
+    while iterable:
+        partitions.append(list(pop_partition()))
+
     return partitions
 
 def round_dict(dic, places):

tests/test_core_util.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+
+import unittest
+import string
+import random
+import sys
+
+from i3pystatus.core import util
+
+def get_random_string(length=6, chars=string.printable):
+    return ''.join(random.choice(chars) for x in range(length))
+
+def lchop_factory(prefix, string):
+    def test():
+        chopped = util.lchop(string, prefix)
+        if string.startswith(prefix):
+            assert len(chopped) == len(string) - len(prefix)
+        if prefix:
+            assert not chopped.startswith(prefix)
+    test.description = "lchop_test:prefix={}:string={}".format(prefix, string)
+    return test
+
+def lchop_test_generator():
+    nmin = 5
+    nmax = 20
+    for n in range(nmin, nmax):
+        prefix = get_random_string(n)
+        string = get_random_string(2*nmax-n)
+        yield lchop_factory(prefix, prefix+string)
+        yield lchop_factory(prefix, string)
+        yield lchop_factory(string, string)
+        yield lchop_factory(string, prefix)
+        yield lchop_factory("", string)
+
+
+def partition_factory(iterable, limit, assrt):
+    def test():
+        partitions = util.partition(iterable, limit)
+        partitions = [sorted(partition) for partition in partitions]
+        for item in assrt:
+            assert sorted(item) in partitions
+    test.description = "partition_test:iterable={}:limit={}:expected={}".format(iterable, limit, assrt)
+    return test
+
+def partition_test_generator():
+    cases = [
+        ([1, 2, 3, 4], 3, [[1,2], [3], [4]]),
+        ([2, 1, 3, 4], 3, [[1,2], [3], [4]]),
+        ([0.33, 0.45, 0.89], 1, [[0.33, 0.45, 0.89]]),
+        ([], 10, []),
+    ]
+
+    for iterable, limit, assrt in cases:
+        yield partition_factory(iterable, limit, assrt)
+
+suite = unittest.TestLoader().loadTestsFromName(__name__)
+unittest.TextTestRunner(verbosity=2).run(suite)