Coverage for tests/test_projection.py: 21%
57 statements
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« prev ^ index » next coverage.py v6.5.0, created at 2023-04-13 09:32 +0000
1# This file is part of daf_relation.
2#
3# Developed for the LSST Data Management System.
4# This product includes software developed by the LSST Project
5# (http://www.lsst.org).
6# See the COPYRIGHT file at the top-level directory of this distribution
7# for details of code ownership.
8#
9# This program is free software: you can redistribute it and/or modify
10# it under the terms of the GNU General Public License as published by
11# the Free Software Foundation, either version 3 of the License, or
12# (at your option) any later version.
13#
14# This program is distributed in the hope that it will be useful,
15# but WITHOUT ANY WARRANTY; without even the implied warranty of
16# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17# GNU General Public License for more details.
18#
19# You should have received a copy of the GNU General Public License
20# along with this program. If not, see <http://www.gnu.org/licenses/>.
22from __future__ import annotations
24import unittest
26from lsst.daf.relation import (
27 ColumnError,
28 ColumnExpression,
29 EngineError,
30 Projection,
31 SortTerm,
32 UnaryOperationRelation,
33 iteration,
34 tests,
35)
38class ProjectionTestCase(tests.RelationTestCase):
39 """Tests for the Projection operation and relations based on it."""
41 def setUp(self) -> None:
42 self.a = tests.ColumnTag("a")
43 self.b = tests.ColumnTag("b")
44 self.c = tests.ColumnTag("c")
45 self.engine = iteration.Engine(name="preferred")
46 self.leaf = self.engine.make_leaf(
47 {self.a, self.b, self.c},
48 payload=iteration.RowSequence(
49 [{self.a: 1, self.b: 4}, {self.a: 0, self.b: 5}, {self.a: 1, self.b: 6}]
50 ),
51 name="leaf",
52 )
54 def test_attributes(self) -> None:
55 """Check that all UnaryOperation and Relation attributes have the
56 expected values.
57 """
58 relation = self.leaf.with_only_columns({self.a})
59 assert isinstance(relation, UnaryOperationRelation)
60 self.assertEqual(relation.columns, {self.a})
61 self.assertEqual(relation.engine, self.engine)
62 self.assertEqual(relation.min_rows, self.leaf.min_rows)
63 self.assertEqual(relation.max_rows, self.leaf.max_rows)
64 operation = relation.operation
65 assert isinstance(operation, Projection)
66 self.assertEqual(operation.columns, {self.a})
67 self.assertEqual(operation.columns_required, {self.a})
68 self.assertTrue(operation.is_empty_invariant)
69 self.assertTrue(operation.is_count_invariant)
70 self.assertFalse(operation.is_order_dependent)
71 self.assertFalse(operation.is_count_dependent)
73 def test_apply_failures(self) -> None:
74 """Test failure modes of constructing and applying Projections."""
75 # Required columns must be present.
76 with self.assertRaises(ColumnError):
77 self.leaf.with_only_columns({self.a, tests.ColumnTag("d")})
79 def test_backtracking_apply(self) -> None:
80 """Test apply logic that involves reordering operations in the existing
81 tree to perform the new operation in a preferred engine.
82 """
83 new_engine = iteration.Engine(name="downstream")
84 d = tests.ColumnTag("d")
85 predicate = ColumnExpression.reference(self.a).lt(ColumnExpression.literal(2))
86 expression = ColumnExpression.function(
87 "__add__", ColumnExpression.reference(self.a), ColumnExpression.literal(5)
88 )
89 sort_terms = [SortTerm(ColumnExpression.reference(self.a))]
90 # Apply a bunch of operations in a new engine that a Projection should
91 # commute with.
92 target = (
93 self.leaf.transferred_to(new_engine)
94 .with_calculated_column(d, expression)
95 .with_rows_satisfying(predicate)
96 .without_duplicates()
97 .sorted(sort_terms)
98 )[:2]
99 # Apply a Projection to just {self.a} and check that it:
100 # - appears before the transfer
101 # - results in the Calculation being dropped (since that now does
102 # nothing).
103 self.assert_relations_equal(
104 target.with_only_columns({self.a}, preferred_engine=self.engine, require_preferred_engine=True),
105 (
106 self.leaf.with_only_columns({self.a})
107 .transferred_to(new_engine)
108 .with_rows_satisfying(predicate)
109 .without_duplicates()
110 .sorted(sort_terms)
111 )[:2],
112 )
113 # Apply a Projection to {self.b}, which cannot be moved past the
114 # calculation or selection in its entirety, since they all depend on
115 # {self.a}. We should move as much of the projection as possible as
116 # far upstream as possible, and leave the rest to be applied in the
117 # non-preferred engine.
118 self.assert_relations_equal(
119 target.with_only_columns({self.b}, preferred_engine=self.engine),
120 (
121 self.leaf.with_only_columns({self.a, self.b})
122 .transferred_to(new_engine)
123 .with_rows_satisfying(predicate)
124 .without_duplicates()
125 .sorted(sort_terms)
126 )[:2].with_only_columns({self.b}),
127 )
128 # Similar attempt with Projection to {self.c}, this time with a
129 # transfer request.
130 self.assert_relations_equal(
131 target.with_only_columns({self.c}, preferred_engine=self.engine, transfer=True),
132 (
133 self.leaf.with_only_columns({self.a, self.c})
134 .transferred_to(new_engine)
135 .with_rows_satisfying(predicate)
136 .without_duplicates()
137 .sorted(sort_terms)
138 )[:2]
139 .transferred_to(self.engine)
140 .with_only_columns({self.c}),
141 )
142 # Test that a projection that does nothing is simplified away.
143 self.assert_relations_equal(self.leaf.with_only_columns(self.leaf.columns), self.leaf)
144 # Test that back-to-back projections and do-nothing calculations are
145 # simplified away, regardless of whether they are before or after the
146 # preferred-engine transfer.
147 target = self.leaf.with_calculated_column(d, expression).transferred_to(new_engine)
148 self.assert_relations_equal(
149 target.with_only_columns({self.a, d}, preferred_engine=self.engine).with_only_columns(
150 {self.a}, preferred_engine=self.engine
151 ),
152 target.with_only_columns({self.a}, preferred_engine=self.engine),
153 )
154 self.assert_relations_equal(
155 target.with_only_columns({self.a, d}).with_only_columns({self.a}, preferred_engine=self.engine),
156 target.with_only_columns({self.a}, preferred_engine=self.engine),
157 )
159 def test_no_backtracking(self) -> None:
160 """Test apply logic that handles preferred engines without reordering
161 operations in the existing tree.
162 """
163 new_engine = iteration.Engine(name="downstream")
164 # Construct a relation tree we can't reorder when inserting a
165 # Projection, because there is a locked Materialization in the way.
166 target = self.leaf.transferred_to(new_engine).materialized("lock")
167 # Preferred engine is ignored if we can't backtrack and don't enable
168 # anything else.
169 self.assert_relations_equal(
170 target.with_only_columns({self.a}, preferred_engine=self.engine),
171 target.with_only_columns({self.a}),
172 )
173 # We can force this to be an error.
174 with self.assertRaises(EngineError):
175 target.with_only_columns({self.a}, preferred_engine=self.engine, require_preferred_engine=True)
176 # We can also automatically transfer (back) to the preferred engine.
177 self.assert_relations_equal(
178 target.with_only_columns({self.a}, preferred_engine=self.engine, transfer=True),
179 target.transferred_to(self.engine).with_only_columns({self.a}),
180 )
182 def test_iteration(self) -> None:
183 """Test Projection execution in the iteration engine."""
184 relation = self.leaf.with_only_columns({self.a})
185 self.assertEqual(
186 list(self.engine.execute(relation)),
187 [{self.a: 1}, {self.a: 0}, {self.a: 1}],
188 )
190 def test_str(self) -> None:
191 """Test str(Projection) and
192 str(UnaryOperationRelation[Projection]).
193 """
194 relation = self.leaf.with_only_columns({self.a})
195 self.assertEqual(str(relation), "Π[a](leaf)")
198if __name__ == "__main__": 198 ↛ 199line 198 didn't jump to line 199, because the condition on line 198 was never true
199 unittest.main()