new: added tests and test case generating function for iputils

.travis.yml

@@ -5,6 +5,6 @@ python:
 # command to install dependencies
 install: "pip install -r requirements.txt . && pip install flake8"
 # command to run tests
-script:
-  - python -m unittest discover -s . -p '*_test.py'
+script: 
+  - pytest
   - flake8 . --count --select=W291,W293,W391 --statistics

capirca/utils/iputils.py

@@ -5,8 +5,8 @@
 import ipaddress
 
 def exclude_address(
-    base_net: ipaddress._BaseNetwork,
-    exclude_net: ipaddress._BaseNetwork
+    base_net: ipaddress._BaseNetwork,    # pylint disable=protected-access
+    exclude_net: ipaddress._BaseNetwork  # pylint disable=protected-access
 ):
   '''
   Function to exclude a subnetwork from another, returning a generator that yields
@@ -29,14 +29,17 @@ def exclude_address(
     A sequence of IP networks that do not encompass the exclude_net
   '''
 
-  if not base_net._version == exclude_net._version:
+  if not isinstance(base_net, ipaddress._BaseNetwork):  # pylint disable=protected-access
+    raise TypeError('%s is not a network object' % base_net)
+
+  if not isinstance(exclude_net, ipaddress._BaseNetwork):  # pylint disable=protected-access
+    raise TypeError('%s is not a network object' % exclude_net)
+
+  if not base_net._version == exclude_net._version:  # pylint disable=protected-access
     raise TypeError(
       '%s and %s are not of the same version' % (base_net, exclude_net)
     )
 
-  if not isinstance(exclude_net, ipaddress._BaseNetwork):
-    raise TypeError('%s is not a network object' % exclude_net)
-
   if not exclude_net.subnet_of(base_net):
     raise ValueError()
   if exclude_net == base_net:

setup.cfg

@@ -0,0 +1,4 @@
+[tool:pytest]
+markers =
+    unit: Marks a unit test
+testpath = tests

tests/utils/iputils_test.py

@@ -0,0 +1,32 @@
+import pytest
+
+import pathlib
+
+from capirca.utils import iputils
+from capirca.lib import nacaddr
+
+
+file_directory = pathlib.Path(__file__).parent.absolute()
+exclude_address_testcases = []
+with open(str(file_directory)+"/address_exclude_test_cases.txt", 'r') as f:
+  for line in f:
+    ipstr, exstrs, restrs = line.strip().split(' ')
+    ip = nacaddr.IP(ipstr)
+    exclude_ips = list(map(nacaddr.IP, exstrs.split(',')))
+    expected_results = []
+    for i in restrs.split(';'):
+      result_strings = i.split(',')
+      ip_map = map(nacaddr.IP, result_strings)
+      ip_list = list(ip_map)
+      expected_results.append(ip_list)
+    for ex, res in zip(exclude_ips, expected_results):
+      exclude_address_testcases.append((ip, ex, res))
+
+class TestIPUtils:
+  @pytest.mark.unit
+  @pytest.mark.parametrize("ip,exclude,expected", exclude_address_testcases)
+  def test_exclude_address(self, ip, exclude, expected):
+    result = iputils.exclude_address(ip, exclude)
+
+    assert list(result) == expected
+

tools/iputilstools.py

@@ -0,0 +1,50 @@
+import random
+import ipaddress
+import itertools as it
+
+
+def write_excludes_testcase(ipstr, excludelist='', max_prefix_range=8, max_random_subnets=30):
+    """
+    Writes a testcase to the tests/utils/address_exclude_test_cases.txt file.
+    Note that the number of prefixes to consider grows exponentially, so unless
+    you *do* want to consider a large pool to randomly select from, keep it at the default
+
+    Args:
+      ipstr: the ip network as a string (v4 or v6) to base the test on.
+      excludelist: optional comma-separated string of ip networks to exclude
+      max_prefix_range: the largest number of prefixes to consider.
+      max_random_subnets: the number of subnets to do exclusion tests for, if randomly generating
+    Returns:
+      None
+    """
+    ip = ipaddress.ip_network(ipstr)
+    if len(excludelist) == 0:  # empty excludelist, making a random one
+        prefixrange = min(max_prefix_range, ip.max_prefixlen - ip.prefixlen)
+        excludelist = it.chain.from_iterable(ip.subnets(i) for i in range(1, prefixrange+1))
+        total_ips = 2**prefixrange
+        ip_positions = set(
+            random.choices(
+                range(total_ips),
+                k=min(
+                    max_random_subnets,
+                    total_ips
+                )
+            )
+        )
+        compress_map = (1 if i in ip_positions else 0 for i in range(total_ips))
+        excludelist = list(it.compress(excludelist, compress_map))
+    else:
+        excludelist = list(map(ipaddress.ip_network, excludelist.split(',')))
+
+    result_list = []
+    for address in excludelist:
+        result_list.append(ip.address_exclude(address))
+
+    ipst = str(ip)
+    exst = ",".join(map(str, excludelist))
+    rest = ";".join(",".join(map(str, sorted(result))) for result in result_list)
+    with open('tests/utils/address_exclude_test_cases.txt', 'a') as f:
+        f.write("%s %s %s\n" % (ipst, exst, rest))
+
+
+