diff --git a/.github/workflows/pull_reqest.yml b/.github/workflows/pull_reqest.yml
index c47817d..df72641 100644
--- a/.github/workflows/pull_reqest.yml
+++ b/.github/workflows/pull_reqest.yml
@@ -12,7 +12,7 @@ jobs:
       - name: Build the stack
         run: docker compose -f "docker-compose.yml" up -d
       - name: Run Tests
-        run: docker compose -f "docker-compose.yml" run web ./bin/ci.sh
+        run: docker compose -f "docker-compose.yml" exec web ./bin/ci.sh
       - name: Stop containers
         if: always()
         run: docker compose -f "docker-compose.yml" down
diff --git a/tests/unit/test_catalogs.py b/tests/unit/test_catalogs.py
index 1cc8e2a..3765ce9 100644
--- a/tests/unit/test_catalogs.py
+++ b/tests/unit/test_catalogs.py
@@ -1,5 +1,6 @@
 """Unit tests for the OAI-PMH DataCite Catalog implementation"""
 
+import pytest
 from viringo import catalogs
 
 def test_set_to_search_query():
@@ -62,9 +63,7 @@ def test_identifier_to_string():
         'type': 'DOI',
         'identifier': "10.5072/1234"
     }
-
     identifier_string = catalogs.identifier_to_string(identifier_type)
-
     assert identifier_string == "doi:10.5072/1234"
 
 def test_numeric_identifier_to_string():
@@ -74,7 +73,28 @@ def test_numeric_identifier_to_string():
         'type': 'ISBN',
         'identifier': 9783851254679
     }
-
     identifier_string = catalogs.identifier_to_string(identifier_type)
-
     assert identifier_string == "isbn:9783851254679"
+
+def test_none_identifier_to_string():
+    """Tests for converting an ISBN numeric identifier to single string"""
+
+    identifier_type = {
+        'type': "ABC",
+        'identifier': None
+    }
+    with pytest.raises(catalogs.InvalidIdentifierException) as exc:
+        identifier_string = catalogs.identifier_to_string(identifier_type)
+    assert exc.type == catalogs.InvalidIdentifierException
+
+def test_none_type_identifier_to_string():
+    """Tests for converting an ISBN numeric identifier to single string"""
+
+    identifier_type = {
+        'type': None,
+        'identifier': 9783851254679
+    }
+    with pytest.raises(catalogs.InvalidIdentifierException) as exc:
+        identifier_string = catalogs.identifier_to_string(identifier_type)
+    assert exc.type == catalogs.InvalidIdentifierException
+
diff --git a/tests/unit/test_service_datacite.py b/tests/unit/test_service_datacite.py
index 74b4ed0..49700bf 100644
--- a/tests/unit/test_service_datacite.py
+++ b/tests/unit/test_service_datacite.py
@@ -13,3 +13,41 @@ def test_strip_uri_prefix():
 
     identifier = datacite.strip_uri_prefix("")
     assert identifier == ""
+
+def test_identifiers():
+    SAMPLE_ATTRIBUTES = {
+        'identifiers': [
+            {
+                'identifierType': 'ISNI',
+                'identifier': 9783851254679
+            },
+        ]
+    }
+
+    assert datacite.identifiers_from_attributes( SAMPLE_ATTRIBUTES ) == [
+        {
+            'type': 'ISNI',
+            'identifier': '9783851254679'
+        }
+    ]
+
+def test_skip_invlaid_identifiers():
+    INVALID_ATTRIBUTES = {
+        'identifiers': [
+            {
+                'identifierType': 'ISBN',
+                'identifier': "XXXXX"
+            },
+            {
+                'identifierType': None,
+                'identifier': 9783851254679
+            },
+        ]
+    }
+
+    assert datacite.identifiers_from_attributes( INVALID_ATTRIBUTES ) == [
+        {
+            'type': 'ISBN',
+            'identifier': 'XXXXX'
+        }
+    ]
diff --git a/viringo/catalogs.py b/viringo/catalogs.py
index 514f032..5afb68f 100644
--- a/viringo/catalogs.py
+++ b/viringo/catalogs.py
@@ -14,6 +14,10 @@
 from .services import datacite
 
 
+class InvalidIdentifierException(Exception):
+    pass
+
+
 class DataCiteOAIServer():
     """Build OAI-PMH data responses for DataCite metadata catalog"""
 
@@ -253,12 +257,15 @@ def build_metadata_map(self, result):
                 rights.append(right['uri'])
 
         identifiers = [
-            identifier_to_string(identifier) for identifier in result.identifiers
+            identifier_to_string(identifier)
+            for identifier in result.identifiers
+            if 'type' in identifier
         ]
 
         relations = [
             identifier_to_string(relation)
             for relation in result.relations
+            if 'type' in relation
         ]
 
         contributors = [
@@ -328,5 +335,9 @@ def set_to_provider_client(unparsed_set):
 def identifier_to_string(identifier):
     """Take an identifier and return in a formatted in single string"""
     _id = identifier.get('identifier')
-    _type = identifier.get('type', '')
+    _type = identifier.get('type','')
+    if not _type:
+        raise InvalidIdentifierException("Missing 'type' information")
+    if not _id:
+        raise InvalidIdentifierException("Missing 'id' information")
     return _type.lower() + ":" + str(_id)
diff --git a/viringo/services/datacite.py b/viringo/services/datacite.py
index 98d4b4e..aa88678 100644
--- a/viringo/services/datacite.py
+++ b/viringo/services/datacite.py
@@ -114,12 +114,10 @@ def build_metadata(data):
         type_ = date.get('dateType')
         value = date.get('date')
         if bool(type_) and bool(value) :
-            result.dates.append(
-                {
-                    'type': type_,
-                    'date': value
-                }
-            )
+            result.dates.append({
+                'type': type_,
+                'date': value
+            })
 
     result.contributors = attributes.get('contributors',[])
     result.funding_references = attributes.get('fundingReferences',[])
@@ -133,37 +131,14 @@ def build_metadata(data):
         if attributes['types'].get('resourceType') is not None else []
 
     result.formats = attributes.get('formats', [])
-
-    result.identifiers = []
-
-    # handle missing identifiers attribute
-    for identifier in attributes.get('identifiers',[]):
-        if identifier['identifier']:
-            # Special handling for the fact the API could return bad identifier
-            # as a list rather than a string
-            if isinstance(identifier['identifier'], list):
-                identifier['identifier'] = ','.join(
-                    identifier['identifier'])
-
-            result.identifiers.append({
-                'type': identifier['identifierType'],
-                'identifier': strip_uri_prefix(identifier['identifier'])
-            })
-
+    result.identifiers = identifiers_from_attributes(attributes)
     result.language = attributes.get('language', '')
-
-    result.relations = []
-    for related in attributes.get('relatedIdentifiers',[]):
-        if 'relatedIdentifier' in related:
-            result.relations.append({
-                'type': related['relatedIdentifierType'],
-                'identifier': related['relatedIdentifier']
-            })
+    result.relations = relations_from_attributes(attributes)
 
     result.rights = [
         {
-            'statement': right.get('rights', None),
-            'uri': right.get('rightsUri', None)
+            'statement': right.get('rights'),
+            'uri': right.get('rightsUri')
         }
         for right in attributes.get('rightsList', [])
     ]
@@ -181,6 +156,33 @@ def build_metadata(data):
 
     return result
 
+def relations_from_attributes(attributes):
+    return identifiers_from_attributes(attributes,
+                                       list_key='relatedIdentifiers',
+                                       type_key='relatedIdentifierType',
+                                       value_key='relatedIdentifier')
+
+def identifiers_from_attributes(attributes,
+                                list_key='identifiers',
+                                type_key='identifierType',
+                                value_key='identifier'):
+    identifiers = []
+    for identifier in attributes.get(list_key,[]):
+        type_ = identifier.get(type_key)
+        value = identifier.get(value_key)
+        if bool(type_) and bool(value) :
+            if isinstance(value, list):
+                value = ','.join( value )
+            if value_key == 'identifier':
+                value = strip_uri_prefix(value)
+            identifiers.append({
+                'type': type_,
+                'identifier': value
+            })
+    return identifiers
+
+
+
 
 def strip_uri_prefix(identifier):
     """Strip common prefixes because OAI doesn't work with those kind of ID's"""