[sonic-cfggen]: Update UT to run yang validation (#9700)

Why I did it
Config db schema generated by minigraph should run yang validation.

How I did it
Modify run_script to add yang validation.

How to verify it
Run sonic-config-engine unit test.

Signed-off-by: Gang Lv ganglv@microsoft.com

src/sonic-config-engine/tests/common_utils.py

@@ -3,10 +3,14 @@
 import os
 import re
 import sys
+import subprocess
+import argparse
+import shlex
 
 PY3x = sys.version_info >= (3, 0)
 PYvX_DIR = "py3" if PY3x else "py2"
 PYTHON_INTERPRETTER = "python3" if PY3x else "python2"
+YANG_MODELS_DIR = "/usr/local/yang-models"
 
 def tuple_to_str(tuplestr):
     """ Convert Python tuple '('elem1', 'elem2')' representation into string on the for "elem1|elem2" """
@@ -33,6 +37,52 @@ def liststr_to_dict(liststr):
 
     return list_obj
 
+class YangWrapper(object):
+    def __init__(self, path=YANG_MODELS_DIR):
+        """
+        sonic_yang only supports python3
+        """
+        if PY3x:
+            import sonic_yang
+            self.yang_parser = sonic_yang.SonicYang(path)
+            self.yang_parser.loadYangModel()
+            self.test_dir = os.path.dirname(os.path.realpath(__file__))
+            self.script_file = PYTHON_INTERPRETTER + ' ' + os.path.join(self.test_dir, '..', 'sonic-cfggen')
+
+    def validate(self, argument):
+        """
+        Raise exception when yang validation failed
+        """
+        if PY3x and "-m" in argument:
+            import sonic_yang
+            parser=argparse.ArgumentParser(description="Render configuration file from minigraph data and jinja2 template.")
+            parser.add_argument("-m", "--minigraph", help="minigraph xml file", nargs='?', const='/etc/sonic/minigraph.xml')
+            parser.add_argument("-k", "--hwsku", help="HwSKU")
+            parser.add_argument("-n", "--namespace", help="namespace name", nargs='?', const=None, default=None)
+            parser.add_argument("-p", "--port-config", help="port config file, used with -m or -k", nargs='?', const=None)
+            parser.add_argument("-S", "--hwsku-config", help="hwsku config file, used with -p and -m or -k", nargs='?', const=None)
+            args, unknown = parser.parse_known_args(shlex.split(argument))
+
+            print('\n    Validating yang schema')
+            cmd = self.script_file + ' -m ' + args.minigraph
+            if args.hwsku is not None:
+                cmd += ' -k ' + args.hwsku
+            if args.hwsku_config is not None:
+                cmd += ' -S ' + args.hwsku_config
+            if args.port_config is not None:
+                cmd += ' -p ' + args.port_config
+            if args.namespace is not None:
+                cmd += ' -n ' + args.namespace
+            cmd += ' --print-data'
+            output = subprocess.check_output(cmd, shell=True).decode()
+            try:
+                self.yang_parser.loadData(configdbJson=json.loads(output))
+                self.yang_parser.validate_data_tree()
+            except sonic_yang.SonicYangException as e:
+                print("yang data generated from %s is not valid: %s"%(args.minigraph, str(e)))
+                return False
+        return True
+
 def cmp(file1, file2):
     """ compare files """
     try:
@@ -43,4 +93,3 @@ def cmp(file1, file2):
         return obj1 == obj2
     except:
         return filecmp.cmp(file1, file2)
-

src/sonic-config-engine/tests/test_cfggen.py

@@ -14,6 +14,7 @@
 class TestCfgGen(TestCase):
 
     def setUp(self):
+        self.yang = utils.YangWrapper()
         self.test_dir = os.path.dirname(os.path.realpath(__file__))
         self.script_file = utils.PYTHON_INTERPRETTER + ' ' + os.path.join(self.test_dir, '..', 'sonic-cfggen')
         self.sample_graph = os.path.join(self.test_dir, 'sample_graph.xml')
@@ -50,6 +51,8 @@ def tearDown(self):
 
     def run_script(self, argument, check_stderr=False, verbose=False):
         print('\n    Running sonic-cfggen ' + argument)
+        self.assertTrue(self.yang.validate(argument))
+
         if check_stderr:
             output = subprocess.check_output(self.script_file + ' ' + argument, stderr=subprocess.STDOUT, shell=True)
         else:

src/sonic-config-engine/tests/test_minigraph_case.py

@@ -14,6 +14,7 @@
 class TestCfgGenCaseInsensitive(TestCase):
 
     def setUp(self):
+        self.yang = utils.YangWrapper()
         self.test_dir = os.path.dirname(os.path.realpath(__file__))
         self.script_file = utils.PYTHON_INTERPRETTER + ' ' + os.path.join(self.test_dir, '..', 'sonic-cfggen')
         self.sample_graph = os.path.join(self.test_dir, 'simple-sample-graph-case.xml')
@@ -24,6 +25,8 @@ def setUp(self):
 
     def run_script(self, argument, check_stderr=False):
         print('\n    Running sonic-cfggen ' + argument)
+        self.assertTrue(self.yang.validate(argument))
+
         if check_stderr:
             output = subprocess.check_output(self.script_file + ' ' + argument, stderr=subprocess.STDOUT, shell=True)
         else:

src/sonic-config-engine/tests/test_multinpu_cfggen.py

@@ -20,6 +20,7 @@
 class TestMultiNpuCfgGen(TestCase):
 
     def setUp(self):
+        self.yang = utils.YangWrapper()
         self.test_dir = os.path.dirname(os.path.realpath(__file__))
         self.test_data_dir = os.path.join(self.test_dir,  'multi_npu_data')
         self.script_file = utils.PYTHON_INTERPRETTER + ' ' + os.path.join(self.test_dir, '..', 'sonic-cfggen')
@@ -34,6 +35,8 @@ def setUp(self):
 
     def run_script(self, argument, check_stderr=False):
         print('\n    Running sonic-cfggen ' + argument)
+        self.assertTrue(self.yang.validate(argument))
+
         if check_stderr:
             output = subprocess.check_output(self.script_file + ' ' + argument, stderr=subprocess.STDOUT, shell=True)
         else: