Add speed and buffer set test (sonic-net#432)

* Add speed and buffer set test

Signed-off-by: Andriy Moroz <c_andriym@mellanox.com>

* Add some comments to the test

Signed-off-by: Andriy Moroz <c_andriym@mellanox.com>

Author: andriymoroz-mlnx

tests/test_speed.py

@@ -0,0 +1,85 @@
+"""
+    test_speed.py implements list of tests to check speed set on
+    interfaces and correct buffer manager behavior on speed change
+
+    These tests need to be run in prepared environment and with the
+    SONiC version compiled for PLATFORM=vs
+
+    See README.md for details
+"""
+from swsscommon import swsscommon
+import time
+import re
+import json
+import os
+
+class TestSpeedSet(object):
+    num_ports = 32
+    def test_SpeedAndBufferSet(self, dvs):
+        speed_list = ['50000', '25000', '40000', '10000', '100000']
+
+        cdb = swsscommon.DBConnector(4, dvs.redis_sock, 0)
+        adb = swsscommon.DBConnector(1, dvs.redis_sock, 0)
+        cfg_port_table = swsscommon.Table(cdb, "PORT", '|')
+        cfg_buffer_profile_table = swsscommon.Table(cdb, "BUFFER_PROFILE", '|')
+        cfg_buffer_pg_table = swsscommon.Table(cdb, "BUFFER_PG", '|')
+        asic_port_table = swsscommon.Table(adb, "ASIC_STATE:SAI_OBJECT_TYPE_PORT")
+        asic_profile_table = swsscommon.Table(adb, "ASIC_STATE:SAI_OBJECT_TYPE_BUFFER_PROFILE")
+
+        buffer_profiles = cfg_buffer_profile_table.getKeys()
+        expected_buffer_profiles_num = len(buffer_profiles)
+        # buffers.json used for the test defines 7 static profiles:
+        #    "ingress_lossless_profile"
+        #    "ingress_lossy_profile"
+        #    "egress_lossless_profile"
+        #    "egress_lossy_profile"
+        #    "pg_lossy_profile"
+        #    "q_lossless_profile"
+        #    "q_lossy_profile"
+        # check if they get the DB
+        assert expected_buffer_profiles_num == 7
+        # and if they were successfully created on ASIC
+        assert len(asic_profile_table.getKeys()) == expected_buffer_profiles_num
+
+        for speed in speed_list:
+            fvs = swsscommon.FieldValuePairs([("speed", speed)])
+            # set same speed on all ports
+            for i in range(0, self.num_ports):
+                cfg_port_table.set("Ethernet%d" % (i*4), fvs)
+
+            time.sleep(1) # let configuration settle down
+
+            # check the speed was set
+            asic_port_records = asic_port_table.getKeys()
+            assert len(asic_port_records) == (self.num_ports + 1) # +CPU port
+            num_set = 0
+            for k in asic_port_records:
+                (status, fvs) = asic_port_table.get(k)
+                assert status == True
+                for fv in fvs:
+                    if fv[0] == "SAI_PORT_ATTR_SPEED":
+                        assert fv[1] == speed
+                        num_set += 1
+            # make sure speed is set for all "num_ports" ports
+            assert num_set == self.num_ports
+
+            # check number of created profiles
+            expected_buffer_profiles_num += 1  # new speed should add new PG profile
+            current_buffer_profiles = cfg_buffer_profile_table.getKeys()
+            assert len(current_buffer_profiles) == expected_buffer_profiles_num
+            # make sure the same number of profiles are created on ASIC
+            assert len(asic_profile_table.getKeys()) == expected_buffer_profiles_num
+
+            # check new profile name
+            expected_new_profile_name = "pg_lossless_%s_300m_profile" % speed
+            assert current_buffer_profiles.index(expected_new_profile_name) > -1
+
+            # check correct profile is set for all ports
+            pg_tables = cfg_buffer_pg_table.getKeys()
+            for i in range(0, self.num_ports):
+                expected_pg_table = "Ethernet%d|3-4" % (i*4)
+                assert pg_tables.index(expected_pg_table) > -1
+                (status, fvs) = cfg_buffer_pg_table.get(expected_pg_table)
+                for fv in fvs:
+                    if fv[0] == "profile":
+                        assert fv[1] == "[BUFFER_PROFILE|%s]" % expected_new_profile_name