Merge pull request #75 from mfalesni/ip-addr-prefix

Enable passing a prefix for IP addresses

AUTHORS.rst

@@ -21,3 +21,4 @@ Contributors
 - Jonathan Edwards `@apense <https://github.com/apense/>`_
 - Kedar Bidarkar  `@kbidarkar <https://github.com/kbidarkar/>`_
 - Sachin Ghai `@sghai <https://github.com/sghai/>`_
+- Milan Falešník `@mfalesni <https://github.com/mfalesni/>`_

fauxfactory/__init__.py

@@ -520,25 +520,53 @@ def gen_negative_integer():
     return gen_integer(max_value=max_value)
 
 
-def gen_ipaddr(ip3=False, ipv6=False):
+def gen_ipaddr(ip3=False, ipv6=False, prefix=()):
     """Generates a random IP address.
 
+    You can also specify an IP address prefix if you are interested in
+    local network address generation, etc.
+
     :param bool ip3: Whether to generate a 3 or 4 group IP.
     :param bool ipv6: Whether to generate IPv6 or IPv4
+    :param list prefix: A prefix to be used for IPv4 (like [10, 0, 1]). It
+        must be an iterable with strings or integers. Can be left unspecified or
+        empty.
     :returns: An IP address.
     :rtype: str
+    :raises: ``ValueError`` if ``prefix`` would lead to no random fields at all.
+        This means the length that triggers the ``ValueError`` is 4 for regular
+        IPv4, 3 for IPv4 with ip3 and 8 for IPv6. It will be raised in any case
+        the prefix length reaches or exceeds those values.
 
     """
 
+    # Set the lengths of the randomly generated sections
+    if ipv6:
+        rng = 8
+    elif ip3:
+        rng = 3
+    else:
+        rng = 4
+    prefix = [str(field) for field in prefix]
+    # Prefix reduces number of random fields generated, so subtract the length
+    # of it from the rng to keep the IP address have correct number of fields
+    rng -= len(prefix)
+    if rng == 0:
+        raise ValueError(
+            "Prefix {} would lead to no randomness at all".format(
+                repr(prefix)))
+    elif rng < 0:
+        raise ValueError(
+            "Prefix {} is too long for this configuration".format(
+                repr(prefix)))
     if ipv6:
         # StackOverflow.com questions: generate-random-ipv6-address
-        ipaddr = u':'.join('{0:x}'.format(
-            random.randint(0, 2**16 - 1)
-        ) for i in range(8))
+        random_fields = [
+            '{0:x}'.format(random.randint(0, 2**16 - 1)) for _ in range(rng)]
+        ipaddr = u':'.join(prefix + random_fields)
     else:
-        rng = 3 if ip3 else 4
-        ipaddr = u".".join(
-            str(random.randrange(0, 255, 1)) for x in range(rng))
+        random_fields = [str(random.randrange(0, 255, 1)) for _ in range(rng)]
+        ipaddr = u".".join(prefix + random_fields)
 
         if ip3:
             ipaddr = ipaddr + u".0"

setup.py

@@ -2,12 +2,14 @@
 # setuptools is preferred over distutils. See:
 # https://packaging.python.org/en/latest/current.html#packaging-tool-recommendations
 from setuptools import find_packages, setup
+import codecs
 import os
 
 
 def read(*paths):
     """Build a file path from *paths* and return the contents."""
-    with open(os.path.join(*paths), 'r') as handle:
+    filename = os.path.join(*paths)
+    with codecs.open(filename, mode='r', encoding="utf-8") as handle:
         return handle.read()
 
 LONG_DESCRIPTION = (read('README.rst') + '\n\n' +

tests/test_ipaddress.py

@@ -63,6 +63,99 @@ def test_gen_ipv4_4(self):
             len(result.split(".")) == 4,
             "Did not generate a 4-group IPv4 addrss")
 
+    def test_gen_ipv4_5(self):
+        """
+        @Test: Generate a 4 group IPv4 address with good prefix
+        @Feature: IPAddr Generator
+        @Assert: A 4-group IPv4 address is generated
+        """
+
+        result = gen_ipaddr(ip3=False, ipv6=False, prefix=[10])
+        self.assertTrue(
+            len(result.split(".")) == 4,
+            "Did not generate a 4-group IPv4 addrss")
+        self.assertTrue(result.startswith("10."))
+
+    def test_gen_ipv4_6(self):
+        """
+        @Test: Generate a 4 group IPv4 address with good prefix
+        @Feature: IPAddr Generator
+        @Assert: A 4-group IPv4 address is generated
+        """
+
+        result = gen_ipaddr(ip3=False, ipv6=False, prefix=[10, 10])
+        self.assertTrue(
+            len(result.split(".")) == 4,
+            "Did not generate a 4-group IPv4 addrss")
+        self.assertTrue(result.startswith("10.10."))
+
+    def test_gen_ipv4_7(self):
+        """
+        @Test: Generate a 4 group IPv4 address with good prefix
+        @Feature: IPAddr Generator
+        @Assert: A 4-group IPv4 address is generated
+        """
+
+        result = gen_ipaddr(ip3=False, ipv6=False, prefix=[10, 10, 10])
+        self.assertTrue(
+            len(result.split(".")) == 4,
+            "Did not generate a 4-group IPv4 addrss")
+        self.assertTrue(result.startswith("10.10.10."))
+
+    def test_gen_ipv4_8(self):
+        """
+        @Test: Generate a 4 group IPv4 address with prefix disabling randomness
+        @Feature: IPAddr Generator
+        @Assert: An exception is raised
+        """
+
+        with self.assertRaises(ValueError):
+            gen_ipaddr(ip3=False, ipv6=False, prefix=[10, 10, 10, 10])
+
+    def test_gen_ipv4_9(self):
+        """
+        @Test: Generate a 4 group IPv4 address with prefix too long
+        @Feature: IPAddr Generator
+        @Assert: An exception is raised
+        """
+
+        with self.assertRaises(ValueError):
+            gen_ipaddr(ip3=False, ipv6=False, prefix=[10, 10, 10, 10, 10])
+
+    def test_gen_ipv4_10(self):
+        """
+        @Test: Generate a 3 group IPv4 address with good prefix
+        @Feature: IPAddr Generator
+        @Assert: A 3-group IPv4 address is generated
+        """
+
+        result = gen_ipaddr(ip3=True, ipv6=False, prefix=[10, 10])
+        self.assertTrue(
+            len(result.split(".")) == 4,
+            "Did not generate a 4-group IPv4 addrss")
+        self.assertTrue(result.startswith("10.10."))
+        self.assertTrue(result.endswith(".0"))
+
+    def test_gen_ipv4_11(self):
+        """
+        @Test: Generate a 3 group IPv4 address with prefix disabling randomness
+        @Feature: IPAddr Generator
+        @Assert: An exception is raised
+        """
+
+        with self.assertRaises(ValueError):
+            gen_ipaddr(ip3=True, ipv6=False, prefix=[10, 10, 10])
+
+    def test_gen_ipv4_12(self):
+        """
+        @Test: Generate a 3 group IPv4 address with prefix too long
+        @Feature: IPAddr Generator
+        @Assert: An exception is raised
+        """
+
+        with self.assertRaises(ValueError):
+            gen_ipaddr(ip3=True, ipv6=False, prefix=[10, 10, 10, 10])
+
     def test_gen_ipv6_1(self):
         """
         @Test: Generate a IPv6 address
@@ -86,3 +179,52 @@ def test_gen_ipv6_2(self):
         self.assertTrue(
             len(result.split(":")) == 8,
             "Did not generate a IPv6 addrss")
+
+    def test_gen_ipv6_3(self):
+        """
+        @Test: Generate a IPv6 address with custom prefix
+        @Feature: IPAddr Generator
+        @Assert: A IPv6 address is generated
+        """
+
+        result = gen_ipaddr(ipv6=True, prefix=["e2d3"])
+        self.assertTrue(
+            len(result.split(":")) == 8,
+            "Did not generate a IPv6 addrss")
+        self.assertTrue(result.startswith("e2d3:"))
+
+    def test_gen_ipv6_4(self):
+        """
+        @Test: Generate a IPv6 address with custom (very long) prefix
+        @Feature: IPAddr Generator
+        @Assert: A IPv6 address is generated
+        """
+
+        prefix = 7 * ["e2d3"]
+        result = gen_ipaddr(ipv6=True, prefix=prefix)
+        self.assertTrue(
+            len(result.split(":")) == 8,
+            "Did not generate a IPv6 addrss")
+        self.assertTrue(result.startswith(":".join(prefix)))
+
+    def test_gen_ipv6_5(self):
+        """
+        @Test: Generate a IPv6 address with too long prefix
+        @Feature: IPAddr Generator
+        @Assert: ValueError raised
+        """
+
+        prefix = 8 * ["e2d3"]
+        with self.assertRaises(ValueError):
+            gen_ipaddr(ipv6=True, prefix=prefix)
+
+    def test_gen_ipv6_6(self):
+        """
+        @Test: Generate a IPv6 address with even longer prefix
+        @Feature: IPAddr Generator
+        @Assert: ValueError raised
+        """
+
+        prefix = 9 * ["e2d3"]
+        with self.assertRaises(ValueError):
+            gen_ipaddr(ipv6=True, prefix=prefix)