diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-acl.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-acl.yang
new file mode 100644
index 000000000000..1aab4d7de0b1
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-acl.yang
@@ -0,0 +1,274 @@
+module sonic-acl {
+
+	yang-version 1.1;
+
+	namespace "http://github.com/Azure/sonic-acl";
+	prefix acl;
+
+	import ietf-yang-types {
+		prefix yang;
+	}
+
+	import ietf-inet-types {
+		prefix inet;
+	}
+
+	import sonic-head {
+		prefix head;
+		revision-date 2019-07-01;
+	}
+
+	import sonic-port {
+		prefix port;
+		revision-date 2019-07-01;
+	}
+
+	import sonic-portchannel {
+		prefix lag;
+		revision-date 2019-07-01;
+	}
+
+	organization "Linkedin Corporation";
+
+	contact "lnos_coders@linkedin.com";
+
+	description "ACL YANG Module for SONiC OS";
+
+	revision 2019-07-01 {
+		description "First Revision";
+	}
+
+	container sonic-acl {
+
+		container ACL_RULE {
+
+			description "ACL_RULE part of config_db.json";
+
+			list ACL_RULE_LIST {
+
+				key "ACL_TABLE_NAME RULE_NAME";
+
+				leaf ACL_TABLE_NAME {
+					type leafref {
+						path "/acl:sonic-acl/acl:ACL_TABLE/acl:ACL_TABLE_LIST/acl:ACL_TABLE_NAME";
+					}
+				}
+
+				leaf RULE_NAME {
+					type string {
+						length 1..255;
+					}
+				}
+
+				leaf PACKET_ACTION {
+					type head:packet_action;
+				}
+
+				leaf IP_TYPE {
+					type head:ip_type;
+				}
+
+				leaf PRIORITY {
+					type uint32 {
+						range 0..999999;
+					}
+				}
+
+				choice ip_prefix {
+
+					case ip4_prefix {
+						when "boolean(IP_TYPE[.='ANY' or .='IP' or .='IPV4' or .='IPV4ANY' or .='ARP'])";
+						leaf SRC_IP {
+							type inet:ipv4-prefix;
+						}
+
+						leaf DST_IP {
+							type inet:ipv4-prefix;
+						}
+					}
+
+					case ip6_prefix {
+						when "boolean(IP_TYPE[.='ANY' or .='IP' or .='IPV6' or .='IPV6ANY'])";
+						leaf SRC_IPV6 {
+							type inet:ipv6-prefix;
+						}
+
+						leaf DST_IPV6 {
+							type inet:ipv6-prefix;
+						}
+					}
+				}
+
+				leaf-list IN_PORTS {
+					/* Values in leaf list are UNIQUE */
+					type uint16;
+				}
+
+				leaf-list OUT_PORTS {
+					/* Values in leaf list are UNIQUE */
+					type uint16;
+				}
+
+				choice src_port {
+					case l4_src_port {
+						leaf L4_SRC_PORT {
+							type uint16;
+						}
+					}
+
+					case l4_src_port_range {
+						leaf L4_SRC_PORT_RANGE {
+							type string {
+								pattern '([0-9]{1,4}|[0-5][0-9]{4}|[6][0-4][0-9]{3}|[6][5][0-2][0-9]{2}|[6][5][3][0-5]{2}|[6][5][3][6][0-5])-([0-9]{1,4}|[0-5][0-9]{4}|[6][0-4][0-9]{3}|[6][5][0-2][0-9]{2}|[6][5][3][0-5]{2}|[6][5][3][6][0-5])';
+							}
+						}
+					}
+				}
+
+				choice dst_port {
+					case l4_dst_port {
+						leaf L4_DST_PORT {
+							type uint16;
+						}
+					}
+
+					case l4_dst_port_range {
+						leaf L4_DST_PORT_RANGE {
+							type string {
+								pattern '([0-9]{1,4}|[0-5][0-9]{4}|[6][0-4][0-9]{3}|[6][5][0-2][0-9]{2}|[6][5][3][0-5]{2}|[6][5][3][6][0-5])-([0-9]{1,4}|[0-5][0-9]{4}|[6][0-4][0-9]{3}|[6][5][0-2][0-9]{2}|[6][5][3][0-5]{2}|[6][5][3][6][0-5])';
+							}
+						}
+					}
+				}
+
+				leaf ETHER_TYPE {
+					type string {
+						pattern "(0x88CC|0x8100|0x8915|0x0806|0x0800|0x86DD|0x8847)";
+					}
+				}
+
+				leaf IP_PROTOCOL {
+					type uint8 {
+						range 1..143;
+					}
+				}
+
+				leaf TCP_FLAGS {
+					type string {
+						pattern '0[x][0-9a-fA-F]{1,2}|0[X][0-9a-fA-F]{1,2}';
+					}
+				}
+
+				leaf DSCP {
+					type uint8;
+				}
+
+				leaf TC {
+					type uint8;
+				}
+
+				choice icmp {
+
+					case icmp4 {
+						when "boolean(IP_TYPE[.='ANY' or .='IP' or .='IPV4' or .='IPV4ANY' or .='ARP'])";
+						leaf ICMP_TYPE {
+							type uint8 {
+								range 1..44;
+							}
+						}
+
+						leaf ICMP_CODE {
+							type uint8 {
+								range 1..16;
+							}
+						}
+					}
+
+					case icmp6 {
+						when "boolean(IP_TYPE[.='ANY' or .='IP' or .='IPV6' or .='IPV6ANY'])";
+						leaf ICMPV6_TYPE {
+							type uint8 {
+								range 1..44;
+							}
+						}
+
+						leaf ICMPV6_CODE {
+							type uint8 {
+								range 1..16;
+							}
+						}
+					}
+				}
+
+				leaf INNER_ETHER_TYPE {
+					type string {
+						pattern "(0x88CC|0x8100|0x8915|0x0806|0x0800|0x86DD|0x8847)";
+					}
+				}
+
+				leaf INNER_IP_PROTOCOL {
+					type uint8 {
+						range 1..143;
+					}
+				}
+
+				leaf INNER_L4_SRC_PORT {
+					type uint16;
+				}
+
+				leaf INNER_L4_DST_PORT {
+					type uint16;
+				}
+			}
+			/* end of ACL_RULE_LIST */
+		}
+		/* end of container ACL_RULE */
+
+		container ACL_TABLE {
+
+			description "ACL_TABLE part of config_db.json";
+
+			list ACL_TABLE_LIST {
+
+				key "ACL_TABLE_NAME";
+
+				leaf ACL_TABLE_NAME {
+					type string;
+				}
+
+				leaf policy_desc {
+					type string {
+						length 1..255;
+					}
+				}
+
+				leaf type {
+					type head:acl_table_type;
+				}
+
+				leaf stage {
+					type enumeration {
+						enum INGRESS;
+						enum EGRESS;
+					}
+				}
+
+				leaf-list ports {
+                    /* union of leafref is allowed in YANG 1.1 */
+					type union {
+						type leafref {
+							path /port:sonic-port/port:PORT/port:PORT_LIST/port:port_name;
+						}
+						type leafref {
+							path /lag:sonic-portchannel/lag:PORTCHANNEL/lag:PORTCHANNEL_LIST/lag:portchannel_name;
+						}
+					}
+				}
+			}
+			/* end of ACL_TABLE_LIST */
+		}
+        /* end of container ACL_TABLE */
+	}
+    /* end of container sonic-acl */
+}
+/* end of module sonic-acl */
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-head.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-head.yang
new file mode 100644
index 000000000000..dd0da92c7152
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-head.yang
@@ -0,0 +1,72 @@
+module sonic-head {
+
+    namespace "http://sonic-head";
+    prefix sonic-head;
+
+    organization "Linkedin Corporation";
+
+    contact "lnos_coders@linkedin.com";
+
+    description "Head yang Module for SONiC OS";
+    
+    revision 2019-07-01 {
+        description "First Revision";
+    }
+    
+    typedef ip-family {
+        type enumeration {
+            enum IPv4;
+            enum IPv6;
+        }
+    }
+
+    typedef admin_status {
+        type enumeration {
+            enum up;
+            enum down;
+        }
+    }
+
+    typedef packet_action{
+        type enumeration {
+            enum DROP;
+            enum FORWARD;
+            enum REDIRECT;
+        }
+    }
+
+    typedef ip_type {
+        type enumeration {
+            enum ANY;
+            enum IP;
+            enum NON_IP;
+            enum IPV4;
+            enum IPV6;
+            enum IPV4ANY;
+            enum NON_IPv4;
+            enum IPV6ANY;
+            enum NON_IPv6;
+            enum ARP;
+        }
+    }
+
+    typedef acl_table_type {
+        type enumeration {
+            enum L2;
+            enum L3;
+            enum L3V6;
+            enum MIRROR;
+            enum MIRRORV6;
+            enum MIRROR_DSCP;
+            enum CTRLPLANE;
+        }
+    }
+
+    typedef vlan_tagging_mode {
+        type enumeration {
+            enum tagged;
+            enum untagged;
+            enum priority_tagged;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-interface.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-interface.yang
new file mode 100644
index 000000000000..dc8bc7389ea1
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-interface.yang
@@ -0,0 +1,78 @@
+module sonic-interface {
+
+	namespace "http://github.com/Azure/sonic-interface";
+	prefix intf;
+
+	import ietf-yang-types {
+		prefix yang;
+	}
+
+	import ietf-inet-types {
+		prefix inet;
+	}
+
+	import sonic-head {
+		prefix head;
+		revision-date 2019-07-01;
+	}
+
+	import sonic-port {
+		prefix port;
+		revision-date 2019-07-01;
+	}
+
+	organization "Linkedin Corporation";
+
+	contact "lnos_coders@linkedin.com";
+
+	description "INTERFACE yang Module for SONiC OS";
+
+	revision 2019-07-01 {
+		description "First Revision";
+	}
+
+	container sonic-interface {
+		container INTERFACE {
+
+			description "INTERFACE part of config_db.json";
+
+			list INTERFACE_LIST {
+
+				key "interface ip-prefix";
+
+				leaf interface {
+					type leafref {
+						path /port:sonic-port/port:PORT/port:PORT_LIST/port:port_name;
+					}
+				}
+
+				leaf ip-prefix {
+					type inet:ip-prefix;
+				}
+
+				leaf scope {
+					type enumeration {
+						enum global;
+						enum local;
+					}
+				}
+
+				leaf family {
+
+					/* family leaf needed for backward compatibility
+					   Both ip4 and ip6 address are string in IETF RFC 6021,
+					   so must statement can check based on : or ., family
+					   should be IPv4 or IPv6 according.
+					 */
+
+					must "(contains(../ip-prefix, ':') and current()='IPv6') or
+						(contains(../ip-prefix, '.') and current()='IPv4')";
+					type head:ip-family;
+				}
+			}
+			/* end of INTERFACE_LIST */
+
+		}
+		/* end of INTERFACE container */
+	}
+}
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-module.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-module.yang
new file mode 100644
index 000000000000..687bb478aacb
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-module.yang
@@ -0,0 +1,144 @@
+module sonic-module {
+  yang-version 1.1;
+  namespace "urn:ietf:params:xml:ns:yang:sonic-module";
+
+  prefix tm;
+
+  import ietf-inet-types {
+    prefix inet;
+  }
+
+  organization "organization";
+  description
+    "example yang module";
+  contact
+    "example@example.org";
+
+   container ports {
+        list port {
+            config true;
+            key "name";
+
+            leaf name {
+                type string;
+            }
+
+            leaf lanes {
+                //choice
+                type uint8;
+            }
+
+/* 
+            leaf fec {
+               type string;
+            }
+
+            leaf mtu {
+                type uint16;
+                description
+                   "Set the max transmission unit size in octets
+                    for the physical interface.  If this is not set, the mtu is
+                    set to the operational default -- e.g., 1514 bytes on an
+                    Ethernet interface.";
+           }
+           leaf admin_status {
+               type enumeration {
+                  enum UP {
+                     description
+                        "Ready to pass packets.";
+                  }
+                  enum DOWN {
+                      description
+                          "Not ready to pass packets and not in some test mode.";
+                  } 
+                  enum TESTING {
+                      //TODO: This is generally not supported as a configured
+                      //admin state, though it's in the standard interfaces MIB.
+                      //Consider removing it.
+                      description
+                         "In some test mode.";
+                   }
+               }
+           }
+*/
+           leaf alias {
+               type string;
+           }
+
+           leaf speed {
+              type string;
+              units "bits/second";
+/*
+              description
+                 "An estimate of the interface's current bandwidth in bits
+                  per second.  For interfaces that do not vary in
+                  bandwidth or for those where no accurate estimation can
+                  be made, this node should contain the nominal bandwidth.
+                  For interfaces that have no concept of bandwidth, this
+                  node is not present.";
+              reference
+                 "RFC 2863: The Interfaces Group MIB -
+                     ifSpeed, ifHighSpeed";
+*/
+           }
+
+        }
+     }
+
+     container vlans {
+        list vlan {
+            config true;
+
+            key "name";
+
+            leaf name {
+                type string;
+            }
+
+            leaf vlanid {
+                type string;
+            }
+
+           leaf admin_status {
+                type string;
+/*
+               type enumeration {
+                  enum UP {
+                     description
+                        "Ready to pass packets.";
+                  }
+                  enum DOWN {
+                      description
+                          "Not ready to pass packets and not in some test mode.";
+                  }
+                  enum TESTING {
+                      //TODO: This is generally not supported as a configured
+                      //admin state, though it's in the standard interfaces MIB.
+                      //Consider removing it.
+                      description
+                         "In some test mode.";
+                   }
+               }
+*/
+           }
+
+           leaf description {
+               type string;
+           }
+
+            leaf mtu {
+                type uint16;
+                description
+                   "Set the max transmission unit size in octets
+                    for the physical interface.  If this is not set, the mtu is
+                    set to the operational default -- e.g., 1514 bytes on an
+                    Ethernet interface.";
+           }
+           leaf-list members {
+                type leafref {
+                     path "../../../ports/port/name";
+                }
+            }
+        }
+    }
+}
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-port.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-port.yang
new file mode 100644
index 000000000000..be04a8aea4bd
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-port.yang
@@ -0,0 +1,84 @@
+module sonic-port{
+
+	namespace "http://github.com/Azure/sonic-port";
+	prefix port;
+
+	import ietf-yang-types {
+		prefix yang;
+	}
+
+	import ietf-inet-types {
+		prefix inet;
+	}
+
+	import sonic-head {
+		prefix head;
+		revision-date 2019-07-01;
+	}
+
+	organization "Linkedin Corporation";
+
+	contact "lnos_coders@linkedin.com";
+
+	description "PORT yang Module for SONiC OS";
+
+	revision 2019-07-01 {
+		description "First Revision";
+	}
+
+	container sonic-port{
+		container PORT {
+
+			description "PORT part of config_db.json";
+
+			list PORT_LIST {
+
+				key "port_name";
+
+				leaf port_name {
+					type string {
+						length 1..128;
+					}
+				}
+
+				leaf alias {
+					type string {
+						length 1..128;
+					}
+				}
+
+				leaf lanes {
+					type string {
+						length 1..128;
+					}
+				}
+
+				leaf description {
+					type string {
+						length 1..255;
+					}
+				}
+
+				leaf speed {
+					type uint32 {
+						range 1..100000;
+					}
+				}
+
+				leaf mtu {
+					type uint16 {
+						range 1..9216;
+					}
+				}
+
+				leaf admin_status {
+					mandatory true;
+					type head:admin_status;
+				}
+			} /* end of list PORT_LIST */
+
+		} /* end of container PORT */
+
+	} /* end of container sonic-port */
+
+} /* end of module sonic-port */
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-portchannel.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-portchannel.yang
new file mode 100644
index 000000000000..656351f4e635
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-portchannel.yang
@@ -0,0 +1,85 @@
+module sonic-portchannel {
+
+	namespace "http://github.com/Azure/sonic-portchannel";
+	prefix lag;
+
+	import ietf-yang-types {
+		prefix yang;
+	}
+
+	import ietf-inet-types {
+		prefix inet;
+	}
+
+	import sonic-head {
+		prefix head;
+		revision-date 2019-07-01;
+	}
+
+	import sonic-port {
+		prefix port;
+		revision-date 2019-07-01;
+	}
+
+	organization "Linkedin Corporation";
+
+	contact "lnos_coders@linkedin.com";
+
+	description "PORTCHANNEL yang Module for SONiC OS";
+
+	revision 2019-07-01 {
+		description "First Revision";
+	}
+
+	container sonic-portchannel {
+		container PORTCHANNEL {
+
+			description "PORTCHANNEL part of config_db.json";
+
+			list PORTCHANNEL_LIST {
+
+				key "portchannel_name";
+
+				leaf portchannel_name {
+					type string {
+						length 1..128;
+						pattern 'PortChannel[0-9]{1,4}';
+					}
+				}
+
+				leaf-list members {
+					/* leaf-list members are unique by default */
+					type leafref {
+						path /port:sonic-port/port:PORT/port:PORT_LIST/port:port_name;
+					}
+				}
+
+				leaf min_links {
+					type uint8 {
+						range 1..128;
+					}
+				}
+
+				leaf description {
+					type string {
+						length 1..255;
+					}
+				}
+
+				leaf mtu {
+					type uint16 {
+						range 1..9216;
+					}
+				}
+
+				leaf admin_status {
+					mandatory true;
+					type head:admin_status;
+				}
+			} /* end of list PORTCHANNEL_LIST */
+
+		} /* end of container PORTCHANNEL */
+
+	} /* end of container sonic-portchannel */
+
+} /* end of module sonic-port */
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-vlan.yang b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-vlan.yang
new file mode 100644
index 000000000000..6058ce3f1bfc
--- /dev/null
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/sonic-vlan.yang
@@ -0,0 +1,158 @@
+module sonic-vlan {
+
+	namespace "http://github.com/Azure/sonic-vlan";
+	prefix vlan;
+
+	import ietf-yang-types {
+		prefix yang;
+	}
+
+	import ietf-inet-types {
+		prefix inet;
+	}
+
+	import sonic-head {
+		prefix head;
+		revision-date 2019-07-01;
+	}
+
+	import sonic-port {
+		prefix port;
+		revision-date 2019-07-01;
+	}
+
+	organization "Linkedin Corporation";
+
+	contact "lnos_coders@linkedin.com";
+
+	description "VLAN yang Module for SONiC OS";
+
+	revision 2019-07-01 {
+		description "First Revision";
+	}
+
+	container sonic-vlan {
+		container VLAN_INTERFACE {
+
+			description "VLAN_INTERFACE part of config_db.json";
+
+			list VLAN_INTERFACE_LIST {
+
+				key "vlanid ip-prefix";
+
+				leaf vlanid {
+					type leafref {
+						path ../../../VLAN/VLAN_LIST/vlanid;
+					}
+				}
+
+				leaf ip-prefix {
+					mandatory true;
+					type inet:ip-prefix;
+				}
+
+				leaf scope {
+					type enumeration {
+						enum global;
+						enum local;
+					}
+				}
+
+				leaf family {
+
+					/* family leaf needed for backward compatibility
+					   Both ip4 and ip6 address are string in IETF RFC 6021,
+					   so must statement can check based on : or ., family
+					   should be IPv4 or IPv6 according.
+					 */
+
+					must "(contains(../ip-prefix, ':') and current()='IPv6') or
+						(contains(../ip-prefix, '.') and current()='IPv4')";
+					type head:ip-family;
+				}
+			}
+			/* end of VLAN_INTERFACE_LIST */
+		}
+		/* end of VLAN_INTERFACE container */
+
+		container VLAN {
+
+			description "VLAN part of config_db.json";
+
+			list VLAN_LIST {
+
+				key "vlanid";
+
+				leaf vlanid {
+					type uint16 {
+						range 1..4094;
+					}
+				}
+
+				leaf description {
+					type string {
+						length 1..255;
+					}
+				}
+
+				leaf-list dhcp_servers {
+					type inet:ip-address;
+				}
+
+				leaf mtu {
+					type uint16 {
+						range 1..9216;
+					}
+				}
+
+				leaf admin_status {
+					mandatory true;
+					type head:admin_status;
+				}
+
+				leaf-list members {
+					/* leaf-list members are unique by default */
+
+					type leafref {
+						path /port:sonic-port/port:PORT/port:PORT_LIST/port:port_name;
+					}
+				}
+			}
+			/* end of VLAN_LIST */
+		}
+		/* end of container VLAN */
+
+		container VLAN_MEMBER {
+
+			description "VLAN_MEMBER part of config_db.json";
+
+			list VLAN_MEMBER_LIST {
+
+				key "vlanid port";
+
+				leaf vlanid {
+					type leafref {
+						path ../../../VLAN/VLAN_LIST/vlanid;
+					}
+				}
+
+				leaf port {
+					/* key elements are mandatory by default */
+					mandatory true;
+					type leafref {
+						path /port:sonic-port/port:PORT/port:PORT_LIST/port:port_name;
+					}
+				}
+
+				leaf tagging_mode {
+					mandatory true;
+					type head:vlan_tagging_mode;
+				}
+			}
+            /* end of list VLAN_MEMBER_LIST */
+		}
+        /* end of container VLAN_MEMBER */
+	}
+    /* end of container sonic-vlan */
+}
+/* end of module sonic-vlan */
diff --git a/src/sonic-yang-mgmt/tests/libyang-python-tests/test_SonicYang.json b/src/sonic-yang-mgmt/tests/libyang-python-tests/test_SonicYang.json
index d7fdff1ac797..fb13168a466c 100644
--- a/src/sonic-yang-mgmt/tests/libyang-python-tests/test_SonicYang.json
+++ b/src/sonic-yang-mgmt/tests/libyang-python-tests/test_SonicYang.json
@@ -1,5 +1,5 @@
 {
-  "yang_dir":"/sonic/src/sonic-yang-mgmt/yang-models/",
+  "yang_dir":"/sonic/src/sonic-yang-mgmt/tests/libyang-python-tests/sample-yang-models/",
   "data_file":"/sonic/src/sonic-yang-mgmt/tests/libyang-python-tests/sonic_config_data.json",
   "data_merge_file":"/sonic/src/sonic-yang-mgmt/tests/libyang-python-tests/sonic_config_data_merge.json",
   "modules":[