#150: Add tests for filter handler

test/icat/test_filter_order_handler.py

@@ -0,0 +1,69 @@
+import pytest
+
+from datagateway_api.common.filter_order_handler import FilterOrderHandler
+from datagateway_api.common.icat.filters import (
+    PythonICATLimitFilter,
+    PythonICATWhereFilter,
+)
+
+
+class TestFilterOrderHandler:
+    """
+    `merge_python_icat_limit_skip_filters` and`clear_python_icat_order_filters()` are
+    tested while testing the ICAT backend filters, so tests of these functions won't be
+    found here
+    """
+
+    def test_add_filter(self, icat_query):
+        test_handler = FilterOrderHandler()
+        test_filter = PythonICATWhereFilter("id", 2, "eq")
+
+        test_handler.add_filter(test_filter)
+
+        assert test_handler.filters == [test_filter]
+
+    def test_add_filters(self):
+        test_handler = FilterOrderHandler()
+        id_filter = PythonICATWhereFilter("id", 2, "eq")
+        name_filter = PythonICATWhereFilter("name", "New Name", "like")
+        filter_list = [id_filter, name_filter]
+
+        test_handler.add_filters(filter_list)
+
+        assert test_handler.filters == filter_list
+
+    def test_remove_filter(self):
+        test_filter = PythonICATWhereFilter("id", 2, "eq")
+
+        test_handler = FilterOrderHandler()
+        test_handler.add_filter(test_filter)
+        test_handler.remove_filter(test_filter)
+
+        assert test_handler.filters == []
+
+    def test_remove_not_added_filter(self):
+        test_handler = FilterOrderHandler()
+        test_filter = PythonICATWhereFilter("id", 2, "eq")
+
+        with pytest.raises(ValueError):
+            test_handler.remove_filter(test_filter)
+
+    def test_sort_filters(self):
+        limit_filter = PythonICATLimitFilter(10)
+        where_filter = PythonICATWhereFilter("id", 2, "eq")
+
+        test_handler = FilterOrderHandler()
+        test_handler.add_filters([limit_filter, where_filter])
+        test_handler.sort_filters()
+
+        assert test_handler.filters == [where_filter, limit_filter]
+
+    def test_apply_filters(self, icat_query):
+        where_filter = PythonICATWhereFilter("id", 2, "eq")
+        limit_filter = PythonICATLimitFilter(10)
+
+        test_handler = FilterOrderHandler()
+        test_handler.add_filters([where_filter, limit_filter])
+        test_handler.apply_filters(icat_query)
+
+        assert icat_query.conditions == {"id": "= '2'"} and icat_query.limit == (0, 10)