Add dtype tests

Author: FBumann

test/test_dtypes.py

@@ -0,0 +1,56 @@
+"""Tests for int32 default label dtype."""
+
+import numpy as np
+import pytest
+
+from linopy import Model
+from linopy.constants import DEFAULT_LABEL_DTYPE
+
+
+def test_default_label_dtype_is_int32():
+    assert DEFAULT_LABEL_DTYPE == np.int32
+
+
+def test_variable_labels_are_int32():
+    m = Model()
+    x = m.add_variables(lower=0, upper=10, coords=[range(5)], name="x")
+    assert x.labels.dtype == np.int32
+
+
+def test_constraint_labels_are_int32():
+    m = Model()
+    x = m.add_variables(lower=0, upper=10, coords=[range(5)], name="x")
+    m.add_constraints(x >= 1, name="c")
+    assert m.constraints["c"].labels.dtype == np.int32
+
+
+def test_expression_vars_are_int32():
+    m = Model()
+    x = m.add_variables(lower=0, upper=10, coords=[range(5)], name="x")
+    expr = 2 * x + 1
+    assert expr.vars.dtype == np.int32
+
+
+def test_solve_with_int32_labels():
+    m = Model()
+    x = m.add_variables(lower=0, upper=10, name="x")
+    y = m.add_variables(lower=0, upper=10, name="y")
+    m.add_constraints(x + y <= 15, name="c1")
+    m.add_objective(x + 2 * y, sense="max")
+    m.solve("highs")
+    assert m.objective.value == pytest.approx(25.0)
+
+
+def test_overflow_guard_variables():
+    m = Model()
+    m._xCounter = np.iinfo(np.int32).max - 1
+    with pytest.raises(ValueError, match="exceeds the maximum"):
+        m.add_variables(lower=0, upper=1, coords=[range(5)], name="x")
+
+
+def test_overflow_guard_constraints():
+    m = Model()
+    x = m.add_variables(lower=0, upper=1, coords=[range(5)], name="x")
+    m._cCounter = np.iinfo(np.int32).max - 1
+    with pytest.raises(ValueError, match="exceeds the maximum"):
+        m.add_constraints(x >= 0, name="c")