[test] Fix and replace failing mock-related tests

Author: chris-evolvedbinary

exist-core/src/test/java/org/exist/xquery/ExceptTest.java

@@ -105,7 +105,7 @@ private static PreorderedValueSequence mockPreorderedValueSequence(final int siz
             expect(mockNode.getNodeId()).andReturn(null);
             expect(mockNode.getNodeType()).andReturn(Node.ELEMENT_NODE);
             expect(mockNode.getInternalAddress()).andReturn(-1l);
-            expect(mockNode.getExpression()).times(1);
+            expect(mockNode.getExpression()).andReturn(null).times(1);
             mockNode.addContextNode(anyInt(), anyObject());
             replay(mockNode);
             valueSequence.add(mockNode);