From 59624d75cb99219c726f10e73bda2bbcae1b3301 Mon Sep 17 00:00:00 2001
From: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>
Date: Tue, 9 Feb 2016 13:00:45 -0400
Subject: [PATCH] Fix GitLab issue #250 "Empty optional lookup metadata trigger
 validation error". Thanks to LeVon Smoker for the find and for the proposed
 fix. Reference:
 https://groups.google.com/forum/#!topic/mayan-edms/VUGRl4xX-1c

---
 mayan/apps/metadata/models.py            |  2 +-
 mayan/apps/metadata/tests/test_models.py | 30 +++++++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/mayan/apps/metadata/models.py b/mayan/apps/metadata/models.py
index 8b4784b27a..619a19aa4a 100644
--- a/mayan/apps/metadata/models.py
+++ b/mayan/apps/metadata/models.py
@@ -126,7 +126,7 @@ class MetadataType(models.Model):
 
         if self.lookup:
             lookup_options = self.get_lookup_values()
-            if value not in lookup_options:
+            if value and value not in lookup_options:
                 raise ValidationError(
                     _('Value is not one of the provided options.')
                 )
diff --git a/mayan/apps/metadata/tests/test_models.py b/mayan/apps/metadata/tests/test_models.py
index 4826a7c64a..3d96286a64 100644
--- a/mayan/apps/metadata/tests/test_models.py
+++ b/mayan/apps/metadata/tests/test_models.py
@@ -63,8 +63,9 @@ class MetadataTestCase(TestCase):
             self.document.metadata_value_of.test, TEST_DEFAULT_VALUE
         )
 
-    def test_lookup(self):
+    def test_lookup_with_incorrect_value(self):
         self.metadata_type.lookup = TEST_LOOKUP_TEMPLATE
+        self.metadata_type.save()
 
         document_metadata = DocumentMetadata(
             document=self.document, metadata_type=self.metadata_type,
@@ -76,8 +77,15 @@ class MetadataTestCase(TestCase):
             document_metadata.full_clean()
             document_metadata.save()
 
-        # Should not return error
-        document_metadata.value = TEST_CORRECT_LOOKUP_VALUE
+    def test_lookup_with_correct_value(self):
+        self.metadata_type.lookup = TEST_LOOKUP_TEMPLATE
+        self.metadata_type.save()
+
+        document_metadata = DocumentMetadata(
+            document=self.document, metadata_type=self.metadata_type,
+            value=TEST_CORRECT_LOOKUP_VALUE
+        )
+
         document_metadata.full_clean()
         document_metadata.save()
 
@@ -85,6 +93,22 @@ class MetadataTestCase(TestCase):
             self.document.metadata_value_of.test, TEST_CORRECT_LOOKUP_VALUE
         )
 
+    def test_empty_optional_lookup(self):
+        """
+        Checks for GitLab issue #250
+        Empty optional lookup metadata trigger validation error
+        """
+
+        self.metadata_type.lookup = TEST_LOOKUP_TEMPLATE
+        self.metadata_type.save()
+
+        document_metadata = DocumentMetadata(
+            document=self.document, metadata_type=self.metadata_type
+        )
+
+        document_metadata.full_clean()
+        document_metadata.save()
+
     def test_validation(self):
         self.metadata_type.validation = TEST_DATE_VALIDATOR