validation NEW duplicate instances

Also trees structure removed, some
refactoring included.
diff --git a/tests/modules/yang/ietf-netconf-with-defaults@2011-06-01.yang b/tests/modules/yang/ietf-netconf-with-defaults@2011-06-01.yang
new file mode 100644
index 0000000..e19d2b3
--- /dev/null
+++ b/tests/modules/yang/ietf-netconf-with-defaults@2011-06-01.yang
@@ -0,0 +1,140 @@
+module ietf-netconf-with-defaults {
+
+   namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults";
+
+   prefix ncwd;
+
+   import ietf-netconf { prefix nc; }
+
+   organization
+    "IETF NETCONF (Network Configuration Protocol) Working Group";
+
+   contact
+    "WG Web:   <http://tools.ietf.org/wg/netconf/>
+
+     WG List:  <netconf@ietf.org>
+
+     WG Chair: Bert Wijnen
+               <bertietf@bwijnen.net>
+
+     WG Chair: Mehmet Ersue
+               <mehmet.ersue@nsn.com>
+
+     Editor: Andy Bierman
+             <andy.bierman@brocade.com>
+
+     Editor: Balazs Lengyel
+             <balazs.lengyel@ericsson.com>";
+
+   description
+    "This module defines an extension to the NETCONF protocol
+     that allows the NETCONF client to control how default
+     values are handled by the server in particular NETCONF
+     operations.
+
+     Copyright (c) 2011 IETF Trust and the persons identified as
+     the document authors.  All rights reserved.
+
+     Redistribution and use in source and binary forms, with or
+     without modification, is permitted pursuant to, and subject
+     to the license terms contained in, the Simplified BSD License
+     set forth in Section 4.c of the IETF Trust's Legal Provisions
+     Relating to IETF Documents
+     (http://trustee.ietf.org/license-info).
+
+     This version of this YANG module is part of RFC 6243; see
+     the RFC itself for full legal notices.";
+
+   revision 2011-06-01 {
+     description
+       "Initial version.";
+     reference
+      "RFC 6243: With-defaults Capability for NETCONF";
+   }
+
+   typedef with-defaults-mode {
+      description
+        "Possible modes to report default data.";
+      reference
+         "RFC 6243; Section 3.";
+      type enumeration {
+         enum report-all {
+             description
+               "All default data is reported.";
+             reference
+               "RFC 6243; Section 3.1";
+         }
+         enum report-all-tagged {
+             description
+               "All default data is reported.
+                Any nodes considered to be default data
+                will contain a 'default' XML attribute,
+                set to 'true' or '1'.";
+             reference
+               "RFC 6243; Section 3.4";
+         }
+         enum trim {
+             description
+               "Values are not reported if they contain the default.";
+             reference
+               "RFC 6243; Section 3.2";
+         }
+         enum explicit {
+             description
+               "Report values that contain the definition of
+                explicitly set data.";
+             reference
+               "RFC 6243; Section 3.3";
+         }
+     }
+   }
+
+   grouping with-defaults-parameters {
+     description
+       "Contains the <with-defaults> parameter for control
+        of defaults in NETCONF retrieval operations.";
+
+     leaf with-defaults {
+       description
+         "The explicit defaults processing mode requested.";
+       reference
+         "RFC 6243; Section 4.5.1";
+
+       type with-defaults-mode;
+     }
+   }
+
+   // extending the get-config operation
+   augment /nc:get-config/nc:input {
+       description
+         "Adds the <with-defaults> parameter to the
+          input of the NETCONF <get-config> operation.";
+       reference
+         "RFC 6243; Section 4.5.1";
+
+       uses with-defaults-parameters;
+   }
+
+   // extending the get operation
+   augment /nc:get/nc:input {
+       description
+         "Adds the <with-defaults> parameter to
+          the input of the NETCONF <get> operation.";
+       reference
+         "RFC 6243; Section 4.5.1";
+
+       uses with-defaults-parameters;
+   }
+
+   // extending the copy-config operation
+   augment /nc:copy-config/nc:input {
+       description
+         "Adds the <with-defaults> parameter to
+          the input of the NETCONF <copy-config> operation.";
+       reference
+         "RFC 6243; Section 4.5.1";
+
+       uses with-defaults-parameters;
+   }
+
+}
diff --git a/tests/modules/yang/ietf-netconf@2011-06-01.yang b/tests/modules/yang/ietf-netconf@2011-06-01.yang
new file mode 100644
index 0000000..6449421
--- /dev/null
+++ b/tests/modules/yang/ietf-netconf@2011-06-01.yang
@@ -0,0 +1,934 @@
+module ietf-netconf {
+
+  // the namespace for NETCONF XML definitions is unchanged
+  // from RFC 4741, which this document replaces
+  namespace "urn:ietf:params:xml:ns:netconf:base:1.0";
+
+  prefix nc;
+
+  import ietf-inet-types {
+    prefix inet;
+  }
+
+  import ietf-netconf-acm { prefix nacm; }
+
+  organization
+    "IETF NETCONF (Network Configuration) Working Group";
+
+  contact
+    "WG Web:   <http://tools.ietf.org/wg/netconf/>
+     WG List:  <netconf@ietf.org>
+
+     WG Chair: Bert Wijnen
+               <bertietf@bwijnen.net>
+
+     WG Chair: Mehmet Ersue
+               <mehmet.ersue@nsn.com>
+
+     Editor:   Martin Bjorklund
+               <mbj@tail-f.com>
+
+     Editor:   Juergen Schoenwaelder
+               <j.schoenwaelder@jacobs-university.de>
+
+     Editor:   Andy Bierman
+               <andy.bierman@brocade.com>";
+  description
+    "NETCONF Protocol Data Types and Protocol Operations.
+
+     Copyright (c) 2011 IETF Trust and the persons identified as
+     the document authors.  All rights reserved.
+
+     Redistribution and use in source and binary forms, with or
+     without modification, is permitted pursuant to, and subject
+     to the license terms contained in, the Simplified BSD License
+     set forth in Section 4.c of the IETF Trust's Legal Provisions
+     Relating to IETF Documents
+     (http://trustee.ietf.org/license-info).
+
+     This version of this YANG module is part of RFC 6241; see
+     the RFC itself for full legal notices.";
+
+  revision 2011-06-01 {
+    description
+      "Initial revision;
+       2013-09-29: Updated to include NACM attributes, 
+       as specified in RFC 6536: sec 3.2.5 and 3.2.8";
+    reference
+      "RFC 6241: Network Configuration Protocol";
+  }
+
+  extension get-filter-element-attributes {
+    description
+      "If this extension is present within an 'anyxml'
+       statement named 'filter', which must be conceptually
+       defined within the RPC input section for the <get>
+       and <get-config> protocol operations, then the
+       following unqualified XML attribute is supported
+       within the <filter> element, within a <get> or
+       <get-config> protocol operation:
+
+         type : optional attribute with allowed
+                value strings 'subtree' and 'xpath'.
+                If missing, the default value is 'subtree'.
+
+       If the 'xpath' feature is supported, then the
+       following unqualified XML attribute is
+       also supported:
+
+         select: optional attribute containing a
+                 string representing an XPath expression.
+                 The 'type' attribute must be equal to 'xpath'
+                 if this attribute is present.";
+  }
+
+  // NETCONF capabilities defined as features
+  feature writable-running {
+    description
+      "NETCONF :writable-running capability;
+       If the server advertises the :writable-running
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.2";
+  }
+
+  feature candidate {
+    description
+      "NETCONF :candidate capability;
+       If the server advertises the :candidate
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.3";
+  }
+
+  feature confirmed-commit {
+    if-feature candidate;
+    description
+      "NETCONF :confirmed-commit:1.1 capability;
+       If the server advertises the :confirmed-commit:1.1
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+
+    reference "RFC 6241, Section 8.4";
+  }
+
+  feature rollback-on-error {
+    description
+      "NETCONF :rollback-on-error capability;
+       If the server advertises the :rollback-on-error
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.5";
+  }
+
+  feature validate {
+    description
+      "NETCONF :validate:1.1 capability;
+       If the server advertises the :validate:1.1
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.6";
+  }
+
+  feature startup {
+    description
+      "NETCONF :startup capability;
+       If the server advertises the :startup
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.7";
+  }
+
+  feature url {
+    description
+      "NETCONF :url capability;
+       If the server advertises the :url
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.8";
+  }
+
+  feature xpath {
+    description
+      "NETCONF :xpath capability;
+       If the server advertises the :xpath
+       capability for a session, then this feature must
+       also be enabled for that session.  Otherwise,
+       this feature must not be enabled.";
+    reference "RFC 6241, Section 8.9";
+  }
+
+  // NETCONF Simple Types
+
+  typedef session-id-type {
+    type uint32 {
+      range "1..max";
+    }
+    description
+      "NETCONF Session Id";
+  }
+
+  typedef session-id-or-zero-type {
+    type uint32;
+    description
+      "NETCONF Session Id or Zero to indicate none";
+  }
+  typedef error-tag-type {
+    type enumeration {
+       enum in-use {
+         description
+           "The request requires a resource that
+            already is in use.";
+       }
+       enum invalid-value {
+         description
+           "The request specifies an unacceptable value for one
+            or more parameters.";
+       }
+       enum too-big {
+         description
+           "The request or response (that would be generated) is
+            too large for the implementation to handle.";
+       }
+       enum missing-attribute {
+         description
+           "An expected attribute is missing.";
+       }
+       enum bad-attribute {
+         description
+           "An attribute value is not correct; e.g., wrong type,
+            out of range, pattern mismatch.";
+       }
+       enum unknown-attribute {
+         description
+           "An unexpected attribute is present.";
+       }
+       enum missing-element {
+         description
+           "An expected element is missing.";
+       }
+       enum bad-element {
+         description
+           "An element value is not correct; e.g., wrong type,
+            out of range, pattern mismatch.";
+       }
+       enum unknown-element {
+         description
+           "An unexpected element is present.";
+       }
+       enum unknown-namespace {
+         description
+           "An unexpected namespace is present.";
+       }
+       enum access-denied {
+         description
+           "Access to the requested protocol operation or
+            data model is denied because authorization failed.";
+       }
+       enum lock-denied {
+         description
+           "Access to the requested lock is denied because the
+            lock is currently held by another entity.";
+       }
+       enum resource-denied {
+         description
+           "Request could not be completed because of
+            insufficient resources.";
+       }
+       enum rollback-failed {
+         description
+           "Request to roll back some configuration change (via
+            rollback-on-error or <discard-changes> operations)
+            was not completed for some reason.";
+
+       }
+       enum data-exists {
+         description
+           "Request could not be completed because the relevant
+            data model content already exists.  For example,
+            a 'create' operation was attempted on data that
+            already exists.";
+       }
+       enum data-missing {
+         description
+           "Request could not be completed because the relevant
+            data model content does not exist.  For example,
+            a 'delete' operation was attempted on
+            data that does not exist.";
+       }
+       enum operation-not-supported {
+         description
+           "Request could not be completed because the requested
+            operation is not supported by this implementation.";
+       }
+       enum operation-failed {
+         description
+           "Request could not be completed because the requested
+            operation failed for some reason not covered by
+            any other error condition.";
+       }
+       enum partial-operation {
+         description
+           "This error-tag is obsolete, and SHOULD NOT be sent
+            by servers conforming to this document.";
+       }
+       enum malformed-message {
+         description
+           "A message could not be handled because it failed to
+            be parsed correctly.  For example, the message is not
+            well-formed XML or it uses an invalid character set.";
+       }
+     }
+     description "NETCONF Error Tag";
+     reference "RFC 6241, Appendix A";
+  }
+
+  typedef error-severity-type {
+    type enumeration {
+      enum error {
+        description "Error severity";
+      }
+      enum warning {
+        description "Warning severity";
+      }
+    }
+    description "NETCONF Error Severity";
+    reference "RFC 6241, Section 4.3";
+  }
+
+  typedef edit-operation-type {
+    type enumeration {
+      enum merge {
+        description
+          "The configuration data identified by the
+           element containing this attribute is merged
+           with the configuration at the corresponding
+           level in the configuration datastore identified
+           by the target parameter.";
+      }
+      enum replace {
+        description
+          "The configuration data identified by the element
+           containing this attribute replaces any related
+           configuration in the configuration datastore
+           identified by the target parameter.  If no such
+           configuration data exists in the configuration
+           datastore, it is created.  Unlike a
+           <copy-config> operation, which replaces the
+           entire target configuration, only the configuration
+           actually present in the config parameter is affected.";
+      }
+      enum create {
+        description
+          "The configuration data identified by the element
+           containing this attribute is added to the
+           configuration if and only if the configuration
+           data does not already exist in the configuration
+           datastore.  If the configuration data exists, an
+           <rpc-error> element is returned with an
+           <error-tag> value of 'data-exists'.";
+      }
+      enum delete {
+        description
+          "The configuration data identified by the element
+           containing this attribute is deleted from the
+           configuration if and only if the configuration
+           data currently exists in the configuration
+           datastore.  If the configuration data does not
+           exist, an <rpc-error> element is returned with
+           an <error-tag> value of 'data-missing'.";
+      }
+      enum remove {
+        description
+          "The configuration data identified by the element
+           containing this attribute is deleted from the
+           configuration if the configuration
+           data currently exists in the configuration
+           datastore.  If the configuration data does not
+           exist, the 'remove' operation is silently ignored
+           by the server.";
+      }
+    }
+    default "merge";
+    description "NETCONF 'operation' attribute values";
+    reference "RFC 6241, Section 7.2";
+  }
+
+  // NETCONF Standard Protocol Operations
+
+  rpc get-config {
+    description
+      "Retrieve all or part of a specified configuration.";
+
+    reference "RFC 6241, Section 7.1";
+
+    input {
+      container source {
+        description
+          "Particular configuration to retrieve.";
+
+        choice config-source {
+          mandatory true;
+          description
+            "The configuration to retrieve.";
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config source.";
+          }
+          leaf running {
+            type empty;
+            description
+              "The running configuration is the config source.";
+          }
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config source.
+               This is optional-to-implement on the server because
+               not all servers will support filtering for this
+               datastore.";
+          }
+        }
+      }
+
+      anyxml filter {
+        description
+          "Subtree or XPath filter to use.";
+        nc:get-filter-element-attributes;
+      }
+    }
+
+    output {
+      anyxml data {
+        description
+          "Copy of the source datastore subset that matched
+           the filter criteria (if any).  An empty data container
+           indicates that the request did not produce any results.";
+      }
+    }
+  }
+
+  rpc edit-config {
+    description
+      "The <edit-config> operation loads all or part of a specified
+       configuration to the specified target configuration.";
+
+    reference "RFC 6241, Section 7.2";
+
+    input {
+      container target {
+        description
+          "Particular configuration to edit.";
+
+        choice config-target {
+          mandatory true;
+          description
+            "The configuration target.";
+
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config target.";
+          }
+          leaf running {
+            if-feature writable-running;
+            type empty;
+            description
+              "The running configuration is the config source.";
+          }
+        }
+      }
+
+      leaf default-operation {
+        type enumeration {
+          enum merge {
+            description
+              "The default operation is merge.";
+          }
+          enum replace {
+            description
+              "The default operation is replace.";
+          }
+          enum none {
+            description
+              "There is no default operation.";
+          }
+        }
+        default "merge";
+        description
+          "The default operation to use.";
+      }
+
+      leaf test-option {
+        if-feature validate;
+        type enumeration {
+          enum test-then-set {
+            description
+              "The server will test and then set if no errors.";
+          }
+          enum set {
+            description
+              "The server will set without a test first.";
+          }
+
+          enum test-only {
+            description
+              "The server will only test and not set, even
+               if there are no errors.";
+          }
+        }
+        default "test-then-set";
+        description
+          "The test option to use.";
+      }
+
+      leaf error-option {
+        type enumeration {
+          enum stop-on-error {
+            description
+              "The server will stop on errors.";
+          }
+          enum continue-on-error {
+            description
+              "The server may continue on errors.";
+          }
+          enum rollback-on-error {
+            description
+              "The server will roll back on errors.
+               This value can only be used if the 'rollback-on-error'
+               feature is supported.";
+          }
+        }
+        default "stop-on-error";
+        description
+          "The error option to use.";
+      }
+
+      choice edit-content {
+        mandatory true;
+        description
+          "The content for the edit operation.";
+
+        anyxml config {
+          description
+            "Inline Config content.";
+        }
+        leaf url {
+          if-feature url;
+          type inet:uri;
+          description
+            "URL-based config content.";
+        }
+      }
+    }
+  }
+
+  rpc copy-config {
+    description
+      "Create or replace an entire configuration datastore with the
+       contents of another complete configuration datastore.";
+
+    reference "RFC 6241, Section 7.3";
+
+    input {
+      container target {
+        description
+          "Particular configuration to copy to.";
+
+        choice config-target {
+          mandatory true;
+          description
+            "The configuration target of the copy operation.";
+
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config target.";
+          }
+          leaf running {
+            if-feature writable-running;
+            type empty;
+            description
+              "The running configuration is the config target.
+               This is optional-to-implement on the server.";
+          }
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config target.";
+          }
+          leaf url {
+            if-feature url;
+            type inet:uri;
+            description
+              "The URL-based configuration is the config target.";
+          }
+        }
+      }
+
+      container source {
+        description
+          "Particular configuration to copy from.";
+
+        choice config-source {
+          mandatory true;
+          description
+            "The configuration source for the copy operation.";
+
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config source.";
+          }
+          leaf running {
+            type empty;
+            description
+              "The running configuration is the config source.";
+          }
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config source.";
+          }
+          leaf url {
+            if-feature url;
+            type inet:uri;
+            description
+              "The URL-based configuration is the config source.";
+          }
+          anyxml config {
+            description
+              "Inline Config content: <config> element.  Represents
+               an entire configuration datastore, not
+               a subset of the running datastore.";
+          }
+        }
+      }
+    }
+  }
+
+  rpc delete-config {
+    nacm:default-deny-all;
+    description
+      "Delete a configuration datastore.";
+
+    reference "RFC 6241, Section 7.4";
+
+    input {
+      container target {
+        description
+          "Particular configuration to delete.";
+
+        choice config-target {
+          mandatory true;
+          description
+            "The configuration target to delete.";
+
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config target.";
+          }
+          leaf url {
+            if-feature url;
+            type inet:uri;
+            description
+              "The URL-based configuration is the config target.";
+          }
+        }
+      }
+    }
+  }
+
+  rpc lock {
+    description
+      "The lock operation allows the client to lock the configuration
+       system of a device.";
+
+    reference "RFC 6241, Section 7.5";
+
+    input {
+      container target {
+        description
+          "Particular configuration to lock.";
+
+        choice config-target {
+          mandatory true;
+          description
+            "The configuration target to lock.";
+
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config target.";
+          }
+          leaf running {
+            type empty;
+            description
+              "The running configuration is the config target.";
+          }
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config target.";
+          }
+        }
+      }
+    }
+  }
+
+  rpc unlock {
+    description
+      "The unlock operation is used to release a configuration lock,
+       previously obtained with the 'lock' operation.";
+
+    reference "RFC 6241, Section 7.6";
+
+    input {
+      container target {
+        description
+          "Particular configuration to unlock.";
+
+        choice config-target {
+          mandatory true;
+          description
+            "The configuration target to unlock.";
+
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config target.";
+          }
+          leaf running {
+            type empty;
+            description
+              "The running configuration is the config target.";
+          }
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config target.";
+          }
+        }
+      }
+    }
+  }
+
+  rpc get {
+    description
+      "Retrieve running configuration and device state information.";
+
+    reference "RFC 6241, Section 7.7";
+
+    input {
+      anyxml filter {
+        description
+          "This parameter specifies the portion of the system
+           configuration and state data to retrieve.";
+        nc:get-filter-element-attributes;
+      }
+    }
+
+    output {
+      anyxml data {
+        description
+          "Copy of the running datastore subset and/or state
+           data that matched the filter criteria (if any).
+           An empty data container indicates that the request did not
+           produce any results.";
+      }
+    }
+  }
+
+  rpc close-session {
+    description
+      "Request graceful termination of a NETCONF session.";
+
+    reference "RFC 6241, Section 7.8";
+  }
+
+  rpc kill-session {
+    nacm:default-deny-all;
+    description
+      "Force the termination of a NETCONF session.";
+
+    reference "RFC 6241, Section 7.9";
+
+    input {
+      leaf session-id {
+        type session-id-type;
+        mandatory true;
+        description
+          "Particular session to kill.";
+      }
+    }
+  }
+
+  rpc commit {
+    if-feature candidate;
+
+    description
+      "Commit the candidate configuration as the device's new
+       current configuration.";
+
+    reference "RFC 6241, Section 8.3.4.1";
+
+    input {
+      leaf confirmed {
+        if-feature confirmed-commit;
+        type empty;
+        description
+          "Requests a confirmed commit.";
+        reference "RFC 6241, Section 8.3.4.1";
+      }
+
+      leaf confirm-timeout {
+        if-feature confirmed-commit;
+        type uint32 {
+          range "1..max";
+        }
+        units "seconds";
+        default "600";   // 10 minutes
+        description
+          "The timeout interval for a confirmed commit.";
+        reference "RFC 6241, Section 8.3.4.1";
+      }
+
+      leaf persist {
+        if-feature confirmed-commit;
+        type string;
+        description
+          "This parameter is used to make a confirmed commit
+           persistent.  A persistent confirmed commit is not aborted
+           if the NETCONF session terminates.  The only way to abort
+           a persistent confirmed commit is to let the timer expire,
+           or to use the <cancel-commit> operation.
+
+           The value of this parameter is a token that must be given
+           in the 'persist-id' parameter of <commit> or
+           <cancel-commit> operations in order to confirm or cancel
+           the persistent confirmed commit.
+
+           The token should be a random string.";
+        reference "RFC 6241, Section 8.3.4.1";
+      }
+
+      leaf persist-id {
+        if-feature confirmed-commit;
+        type string;
+        description
+          "This parameter is given in order to commit a persistent
+           confirmed commit.  The value must be equal to the value
+           given in the 'persist' parameter to the <commit> operation.
+           If it does not match, the operation fails with an
+          'invalid-value' error.";
+        reference "RFC 6241, Section 8.3.4.1";
+      }
+
+    }
+  }
+
+  rpc discard-changes {
+    if-feature candidate;
+
+    description
+      "Revert the candidate configuration to the current
+       running configuration.";
+    reference "RFC 6241, Section 8.3.4.2";
+  }
+
+  rpc cancel-commit {
+    if-feature confirmed-commit;
+    description
+      "This operation is used to cancel an ongoing confirmed commit.
+       If the confirmed commit is persistent, the parameter
+       'persist-id' must be given, and it must match the value of the
+       'persist' parameter.";
+    reference "RFC 6241, Section 8.4.4.1";
+
+    input {
+      leaf persist-id {
+        type string;
+        description
+          "This parameter is given in order to cancel a persistent
+           confirmed commit.  The value must be equal to the value
+           given in the 'persist' parameter to the <commit> operation.
+           If it does not match, the operation fails with an
+          'invalid-value' error.";
+      }
+    }
+  }
+
+  rpc validate {
+    if-feature validate;
+
+    description
+      "Validates the contents of the specified configuration.";
+
+    reference "RFC 6241, Section 8.6.4.1";
+
+    input {
+      container source {
+        description
+          "Particular configuration to validate.";
+
+        choice config-source {
+          mandatory true;
+          description
+            "The configuration source to validate.";
+
+          leaf candidate {
+            if-feature candidate;
+            type empty;
+            description
+              "The candidate configuration is the config source.";
+          }
+          leaf running {
+            type empty;
+            description
+              "The running configuration is the config source.";
+          }
+          leaf startup {
+            if-feature startup;
+            type empty;
+            description
+              "The startup configuration is the config source.";
+          }
+          leaf url {
+            if-feature url;
+            type inet:uri;
+            description
+              "The URL-based configuration is the config source.";
+          }
+          anyxml config {
+            description
+              "Inline Config content: <config> element.  Represents
+               an entire configuration datastore, not
+               a subset of the running datastore.";
+          }
+        }
+      }
+    }
+  }
+
+}