Merge commit '81396a5322a7a48764fcf254d5d933ba1e57bdc5' as 'kiwi'

kiwi/py/tests/test_constraint.py

@@ -0,0 +1,84 @@
+# --------------------------------------------------------------------------------------
+# Copyright (c) 2014-2021, Nucleic Development Team.
+#
+# Distributed under the terms of the Modified BSD License.
+#
+# The full license is in the file LICENSE, distributed with this software.
+# --------------------------------------------------------------------------------------
+import gc
+import re
+
+import pytest
+
+from kiwisolver import Constraint, Variable, strength
+
+
+@pytest.mark.parametrize("op", ("==", "<=", ">="))
+def test_constraint_creation(op) -> None:
+    """Test constraints creation and methods."""
+    v = Variable("foo")
+    c = Constraint(v + 1, op)
+
+    assert c.strength() == strength.required and c.op() == op
+    e = c.expression()
+    t = e.terms()
+    assert (
+        e.constant() == 1
+        and len(t) == 1
+        and t[0].variable() is v
+        and t[0].coefficient() == 1
+    )
+
+    constraint_format = r"1 \* foo \+ 1 %s 0 | strength = 1.001e\+[0]+9" % op
+    assert re.match(constraint_format, str(c))
+
+    for s in ("weak", "medium", "strong", "required"):
+        # Not an exact literal...
+        c = Constraint(v + 1, op, s)  # type: ignore
+        assert c.strength() == getattr(strength, s)
+
+    # Ensure we test garbage collection.
+    del c
+    gc.collect()
+
+
+def test_constraint_creation2() -> None:
+    """Test for errors in Constraints creation."""
+    v = Variable("foo")
+
+    with pytest.raises(TypeError) as excinfo:
+        Constraint(1, "==")  # type: ignore
+    assert "Expression" in excinfo.exconly()
+
+    with pytest.raises(TypeError) as excinfo:
+        Constraint(v + 1, 1)  # type: ignore
+    assert "str" in excinfo.exconly()
+
+    with pytest.raises(ValueError) as excinfo2:
+        Constraint(v + 1, "!=")  # type: ignore
+    assert "relational operator" in excinfo2.exconly()
+
+
+@pytest.mark.parametrize("op", ("==", "<=", ">="))
+def test_constraint_repr(op) -> None:
+    """Test the repr method of a constraint object."""
+    v = Variable("foo")
+    c = Constraint(v + 1, op)
+
+    assert op in repr(c)
+
+
+def test_constraint_or_operator() -> None:
+    """Test modifying a constraint strength using the | operator."""
+    v = Variable("foo")
+    c = Constraint(v + 1, "==")
+
+    for s in ("weak", "medium", "strong", "required", strength.create(1, 1, 0)):
+        c2 = c | s  # type: ignore
+        if isinstance(s, str):
+            assert c2.strength() == getattr(strength, s)
+        else:
+            assert c2.strength() == s
+
+    with pytest.raises(ValueError):
+        c | "unknown"  # type: ignore