From 25409b2099c8c56771aeaa82b3ae9abb08989a27 Mon Sep 17 00:00:00 2001
From: Greg Back <gback@mitre.org>
Date: Thu, 5 Jul 2018 11:25:48 -0500
Subject: [PATCH] GH-188: Update error message for invalid IDs.

---
 stix2/properties.py           |  8 ++++++--
 stix2/test/test_properties.py | 15 ++++++++-------
 stix2/test/test_report.py     |  4 ++--
 3 files changed, 16 insertions(+), 11 deletions(-)

diff --git a/stix2/properties.py b/stix2/properties.py
index 871e8fd..1fc0e7c 100644
--- a/stix2/properties.py
+++ b/stix2/properties.py
@@ -25,6 +25,10 @@ ID_REGEX = re.compile("^[a-z0-9][a-z0-9-]+[a-z0-9]--"  # object type
                       "[89abAB][0-9a-fA-F]{3}-"
                       "[0-9a-fA-F]{12}$")
 
+ERROR_INVALID_ID = (
+    "not a valid STIX identifier, must match <object-type>--<UUIDv4>"
+)
+
 
 class Property(object):
     """Represent a property of STIX data type.
@@ -183,7 +187,7 @@ class IDProperty(Property):
         if not value.startswith(self.required_prefix):
             raise ValueError("must start with '{0}'.".format(self.required_prefix))
         if not ID_REGEX.match(value):
-            raise ValueError("must have a valid UUID after the prefix.")
+            raise ValueError(ERROR_INVALID_ID)
         return value
 
     def default(self):
@@ -331,7 +335,7 @@ class ReferenceProperty(Property):
             if not value.startswith(self.type):
                 raise ValueError("must start with '{0}'.".format(self.type))
         if not ID_REGEX.match(value):
-            raise ValueError("must match <object-type>--<guid>.")
+            raise ValueError(ERROR_INVALID_ID)
         return value
 
 
diff --git a/stix2/test/test_properties.py b/stix2/test/test_properties.py
index 6280c57..1106bcb 100644
--- a/stix2/test/test_properties.py
+++ b/stix2/test/test_properties.py
@@ -4,12 +4,13 @@ import pytest
 
 from stix2 import CustomObject, EmailMIMEComponent, ExtensionsProperty, TCPExt
 from stix2.exceptions import AtLeastOnePropertyError, DictionaryKeyError
-from stix2.properties import (BinaryProperty, BooleanProperty,
-                              DictionaryProperty, EmbeddedObjectProperty,
-                              EnumProperty, FloatProperty, HashesProperty,
-                              HexProperty, IDProperty, IntegerProperty,
-                              ListProperty, Property, ReferenceProperty,
-                              StringProperty, TimestampProperty, TypeProperty)
+from stix2.properties import (ERROR_INVALID_ID, BinaryProperty,
+                              BooleanProperty, DictionaryProperty,
+                              EmbeddedObjectProperty, EnumProperty,
+                              FloatProperty, HashesProperty, HexProperty,
+                              IDProperty, IntegerProperty, ListProperty,
+                              Property, ReferenceProperty, StringProperty,
+                              TimestampProperty, TypeProperty)
 
 from . import constants
 
@@ -143,7 +144,7 @@ def test_id_property_wrong_type():
 def test_id_property_not_a_valid_hex_uuid(value):
     with pytest.raises(ValueError) as excinfo:
         ID_PROP.clean(value)
-    assert str(excinfo.value) == "must have a valid UUID after the prefix."
+    assert str(excinfo.value) == ERROR_INVALID_ID
 
 
 def test_id_property_default():
diff --git a/stix2/test/test_report.py b/stix2/test/test_report.py
index b38ab40..9999877 100644
--- a/stix2/test/test_report.py
+++ b/stix2/test/test_report.py
@@ -87,8 +87,8 @@ def test_report_example_objects_in_object_refs_with_bad_id():
 
     assert excinfo.value.cls == stix2.Report
     assert excinfo.value.prop_name == "object_refs"
-    assert excinfo.value.reason == "must match <object-type>--<guid>."
-    assert str(excinfo.value) == "Invalid value for Report 'object_refs': must match <object-type>--<guid>."
+    assert excinfo.value.reason == stix2.properties.ERROR_INVALID_ID
+    assert str(excinfo.value) == "Invalid value for Report 'object_refs': " + stix2.properties.ERROR_INVALID_ID
 
 
 @pytest.mark.parametrize("data", [