tests: replace pycodestyle with black

Drop pycodestyle for code style checking in favor of black. Black is
much faster, stable PEP8 compliant code style checker offering also
automatic formatting. It aims to be very stable and produce smallest
diffs. It's used by many small and big projects.

Running checkstyle with black takes a few seconds with a terse output.
Thus, test-checkstyle-diff is no longer necessary.

Expand scope of checkstyle to all python files in the repo, replacing
test-checkstyle with checkstyle-python.

Also, fixstyle-python is now available for automatic style formatting.

Note: python virtualenv has been consolidated in test/Makefile,
test/requirements*.txt which will eventually be moved to a central
location.  This is required to simply the automated generation of
docker executor images in the CI.

Type: improvement
Change-Id: I022a326603485f58585e879ac0f697fceefbc9c8
Signed-off-by: Klement Sekera <klement.sekera@gmail.com>
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
diff --git a/test/test_l3xc.py b/test/test_l3xc.py
index 2bcb6d5..66eb242 100644
--- a/test/test_l3xc.py
+++ b/test/test_l3xc.py
@@ -28,8 +28,7 @@
 
 
 class VppL3xc(VppObject):
-
-    def __init__(self,  test, intf, paths, is_ip6=False):
+    def __init__(self, test, intf, paths, is_ip6=False):
         self._test = test
         self.intf = intf
         self.is_ip6 = is_ip6
@@ -41,27 +40,26 @@
     def add_vpp_config(self):
         self._test.vapi.l3xc_update(
             l3xc={
-                'is_ip6': self.is_ip6,
-                'sw_if_index': self.intf.sw_if_index,
-                'n_paths': len(self.paths),
-                'paths': self.encoded_paths
-            })
+                "is_ip6": self.is_ip6,
+                "sw_if_index": self.intf.sw_if_index,
+                "n_paths": len(self.paths),
+                "paths": self.encoded_paths,
+            }
+        )
         self._test.registry.register(self, self._test.logger)
 
     def remove_vpp_config(self):
-        self._test.vapi.l3xc_del(
-            is_ip6=self.is_ip6,
-            sw_if_index=self.intf.sw_if_index)
+        self._test.vapi.l3xc_del(is_ip6=self.is_ip6, sw_if_index=self.intf.sw_if_index)
 
     def query_vpp_config(self):
         return find_l3xc(self._test, self.intf.sw_if_index)
 
     def object_id(self):
-        return ("l3xc-%d" % self.intf.sw_if_index)
+        return "l3xc-%d" % self.intf.sw_if_index
 
 
 class TestL3xc(VppTestCase):
-    """ L3XC Test Case """
+    """L3XC Test Case"""
 
     @classmethod
     def setUpClass(cls):
@@ -91,25 +89,27 @@
         super(TestL3xc, self).tearDown()
 
     def test_l3xc4(self):
-        """ IPv4 X-Connect """
+        """IPv4 X-Connect"""
 
         #
         # x-connect pg0 to pg1 and pg2 to pg3->5
         #
-        l3xc_1 = VppL3xc(self, self.pg0,
-                         [VppRoutePath(self.pg1.remote_ip4,
-                                       self.pg1.sw_if_index)])
+        l3xc_1 = VppL3xc(
+            self, self.pg0, [VppRoutePath(self.pg1.remote_ip4, self.pg1.sw_if_index)]
+        )
         l3xc_1.add_vpp_config()
-        l3xc_2 = VppL3xc(self, self.pg2,
-                         [VppRoutePath(self.pg3.remote_ip4,
-                                       self.pg3.sw_if_index),
-                          VppRoutePath(self.pg4.remote_ip4,
-                                       self.pg4.sw_if_index),
-                          VppRoutePath(self.pg5.remote_ip4,
-                                       self.pg5.sw_if_index)])
+        l3xc_2 = VppL3xc(
+            self,
+            self.pg2,
+            [
+                VppRoutePath(self.pg3.remote_ip4, self.pg3.sw_if_index),
+                VppRoutePath(self.pg4.remote_ip4, self.pg4.sw_if_index),
+                VppRoutePath(self.pg5.remote_ip4, self.pg5.sw_if_index),
+            ],
+        )
         l3xc_2.add_vpp_config()
 
-        self.assertTrue(find_l3xc(self, self.pg2.sw_if_index, 0xffffffff))
+        self.assertTrue(find_l3xc(self, self.pg2.sw_if_index, 0xFFFFFFFF))
 
         self.logger.info(self.vapi.cli("sh l3xc"))
 
@@ -117,26 +117,29 @@
         # fire in packets. If it's forwarded then the L3XC was successful,
         # since default routing will drop it
         #
-        p_1 = (Ether(src=self.pg0.remote_mac,
-                     dst=self.pg0.local_mac) /
-               IP(src="1.1.1.1", dst="1.1.1.2") /
-               UDP(sport=1234, dport=1234) /
-               Raw(b'\xa5' * 100))
+        p_1 = (
+            Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
+            / IP(src="1.1.1.1", dst="1.1.1.2")
+            / UDP(sport=1234, dport=1234)
+            / Raw(b"\xa5" * 100)
+        )
         # self.send_and_expect(self.pg0, p_1*NUM_PKTS, self.pg1)
 
         p_2 = []
         for ii in range(NUM_PKTS):
-            p_2.append(Ether(src=self.pg0.remote_mac,
-                             dst=self.pg0.local_mac) /
-                       IP(src="1.1.1.1", dst="1.1.1.2") /
-                       UDP(sport=1000 + ii, dport=1234) /
-                       Raw(b'\xa5' * 100))
-        self.send_and_expect_load_balancing(self.pg2, p_2,
-                                            [self.pg3, self.pg4, self.pg5])
+            p_2.append(
+                Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
+                / IP(src="1.1.1.1", dst="1.1.1.2")
+                / UDP(sport=1000 + ii, dport=1234)
+                / Raw(b"\xa5" * 100)
+            )
+        self.send_and_expect_load_balancing(
+            self.pg2, p_2, [self.pg3, self.pg4, self.pg5]
+        )
 
         l3xc_2.remove_vpp_config()
         self.send_and_assert_no_replies(self.pg2, p_2)
 
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     unittest.main(testRunner=VppTestRunner)