More tests for almasru (multiple, unique, not_unique)

sru/tests/test_almasru.py

 import pytest
 import sru.almasru as almasru
 
-retriever = almasru.RecordRetriever('obv-at-oenb', '43ACC_ONB', 'marcxml')
+RETRIEVER = almasru.RecordRetriever('obv-at-oenb', '43ACC_ONB', 'marcxml')
 
 
 class TestRecordRetriever:
 
     def test_erroneous_xml(self):
         with pytest.raises(almasru.SruException):
-            retriever.by_mms_id('MMS-ID')
+            RETRIEVER.by_mms_id('MMS-ID')
 
+    def test_get_multiple(self):
+        query = "alma.local_control_field_009=AC13320616 OR alma.local_control_field_009=AC13320328"
+        RETRIEVER.get_multiple(query)
+        assert True
+
+    def test_get_unique(self):
+        query = "alma.local_control_field_009=AC13320616"
+        RETRIEVER.get_unique(query)
+        assert True
+
+    def test_not_unique(self):
+        query = "alma.local_control_field_009=AC13320616 OR alma.local_control_field_009=AC13320328"
+        with pytest.raises(almasru.NotUnique):
+            RETRIEVER.get_unique(query)