[Tests] Add comprehensive tests for objective functions and penalties

Author: Pabloo22

tests/metaheuristics/test_objective_functions.py

@@ -0,0 +1,108 @@
+# pylint: disable=missing-function-docstring, redefined-outer-name
+import pytest
+
+from job_shop_lib import (
+    JobShopInstance,
+    Operation,
+    Schedule,
+    ScheduledOperation,
+)
+from job_shop_lib.metaheuristics import (
+    get_makespan_with_penalties_objective,
+    compute_penalty_for_deadlines,
+    compute_penalty_for_due_dates,
+)
+
+
+@pytest.fixture
+def schedule_no_penalties() -> Schedule:
+    # Two machines; set due_date/deadline None
+    jobs = [[Operation(0, 2)], [Operation(1, 3)]]
+    instance = JobShopInstance(jobs, name="NoPenalties")
+    # Build schedule manually: M0: job0@t0..2; M1: job1@t0..3
+    s0 = ScheduledOperation(instance.jobs[0][0], start_time=0, machine_id=0)
+    s1 = ScheduledOperation(instance.jobs[1][0], start_time=0, machine_id=1)
+    schedule = Schedule(instance, [[s0], [s1]])
+    return schedule
+
+
+@pytest.fixture
+def schedule_with_deadlines() -> Schedule:
+    # Single machine sequence; second op violates deadline
+    jobs = [
+        [Operation(0, 2, deadline=1)],  # ends at 2 -> violation
+        [Operation(0, 3, deadline=5)],  # ends at 5 -> boundary, no violation
+    ]
+    instance = JobShopInstance(jobs, name="Deadlines")
+    s0 = ScheduledOperation(instance.jobs[0][0], start_time=0, machine_id=0)
+    s1 = ScheduledOperation(instance.jobs[1][0], start_time=2, machine_id=0)
+    schedule = Schedule(instance, [[s0, s1]])
+    return schedule
+
+
+@pytest.fixture
+def schedule_with_due_dates() -> Schedule:
+    # Single machine sequence; first op OK, second violates due date
+    jobs = [
+        [Operation(0, 1, due_date=1)],  # ends at 1 -> equal, OK
+        [Operation(0, 4, due_date=3)],  # ends at 5 -> violation
+    ]
+    instance = JobShopInstance(jobs, name="DueDates")
+    s0 = ScheduledOperation(instance.jobs[0][0], start_time=0, machine_id=0)
+    s1 = ScheduledOperation(instance.jobs[1][0], start_time=1, machine_id=0)
+    schedule = Schedule(instance, [[s0, s1]])
+    return schedule
+
+
+@pytest.fixture
+def schedule_with_both() -> Schedule:
+    # Mixed: first violates deadline, second violates due date
+    jobs = [
+        [Operation(0, 3, deadline=2, due_date=10)],  # deadline violation
+        [Operation(0, 4, deadline=10, due_date=6)],  # due date violation
+    ]
+    instance = JobShopInstance(jobs, name="Both")
+    s0 = ScheduledOperation(instance.jobs[0][0], start_time=0, machine_id=0)
+    s1 = ScheduledOperation(instance.jobs[1][0], start_time=3, machine_id=0)
+    schedule = Schedule(instance, [[s0, s1]])
+    return schedule
+
+
+def test_compute_penalty_for_deadlines_none(schedule_no_penalties: Schedule):
+    assert compute_penalty_for_deadlines(schedule_no_penalties, 1000) == 0.0
+
+
+def test_compute_penalty_for_due_dates_none(schedule_no_penalties: Schedule):
+    assert compute_penalty_for_due_dates(schedule_no_penalties, 100) == 0.0
+
+
+def test_compute_penalty_for_deadlines(schedule_with_deadlines: Schedule):
+    # Only first op violates -> 1 penalty
+    assert compute_penalty_for_deadlines(schedule_with_deadlines, 7.5) == 7.5
+
+
+def test_compute_penalty_for_due_dates(schedule_with_due_dates: Schedule):
+    # Only second op violates -> 1 penalty
+    assert compute_penalty_for_due_dates(schedule_with_due_dates, 3.0) == 3.0
+
+
+def test_objective_makespan_only_when_zero_factors(
+    schedule_with_both: Schedule,
+):
+    objective = get_makespan_with_penalties_objective(
+        deadline_penalty_factor=0, due_date_penalty_factor=0
+    )
+    assert objective(schedule_with_both) == schedule_with_both.makespan()
+
+
+def test_objective_with_penalties(schedule_with_both: Schedule):
+    # s0: 0..3 (violates deadline=2) -> +d_factor
+    # s1: 3..7 (violates due_date=6) -> +dd_factor
+    d_factor = 123.0
+    dd_factor = 4.0
+    objective = get_makespan_with_penalties_objective(
+        deadline_penalty_factor=d_factor,
+        due_date_penalty_factor=dd_factor,
+    )
+    expected = schedule_with_both.makespan() + d_factor + dd_factor
+    assert objective(schedule_with_both) == expected