Fix and test timeout parameter bug

main.py

@@ -57,7 +57,7 @@ async def solve_constraint_core(problem: ConstraintModel) -> "SolveResult":
         if problem.timeout:
             result = await instance.solve_async(
                 all_solutions=problem.all_solutions,
-                timeout=datetime.timedelta(seconds=problem.timeout)
+                time_limit=datetime.timedelta(seconds=problem.timeout)
             )
         else:
             result = await instance.solve_async(all_solutions=problem.all_solutions)

tests/test_timeout.py

@@ -1,4 +1,5 @@
 import pytest
+import time
 from main import ConstraintModel, solve_constraint_core
 
 
@@ -12,3 +13,62 @@ async def test_timeout_param_smoke():
     res = await solve_constraint_core(problem)
     assert res.status != "ERROR"
     assert res.num_solutions >= 1
+
+
+@pytest.mark.asyncio
+async def test_timeout_actually_times_out():
+    """Test that timeout parameter actually interrupts long-running computation"""
+    # Create a problem that would take a very long time to solve completely
+    # Finding all solutions to 14-queens would take a VERY long time (minutes/hours)
+    problem = ConstraintModel(
+        model="""
+        include "alldifferent.mzn";
+        int: n = 14;
+        array[1..n] of var 1..n: queens;
+        constraint alldifferent(queens);
+        constraint alldifferent([queens[i] + i | i in 1..n]);
+        constraint alldifferent([queens[i] - i | i in 1..n]);
+        solve satisfy;
+        """,
+        solver="gecode",
+        all_solutions=True,  # This would take HOURS for n=14
+        timeout=2,  # But we'll timeout after 2 seconds
+    )
+
+    start_time = time.time()
+    res = await solve_constraint_core(problem)
+    elapsed_time = time.time() - start_time
+
+    print(f"Result status: {res.status}")
+    print(f"Number of solutions: {res.num_solutions}")
+    print(f"Elapsed time: {elapsed_time:.2f}s")
+    print(f"Error (if any): {res.error}")
+    print(f"Solve time from result: {res.solve_time}")
+
+    # The solver should stop around the timeout duration
+    # Allow some overhead (up to 5 seconds for 2 second timeout)
+    assert elapsed_time < 5, f"Solver ran for {elapsed_time}s, should have timed out around 2s"
+
+    # The elapsed time should be at least close to the timeout
+    # (accounting for some overhead, should be at least 1.5 seconds)
+    assert elapsed_time >= 1.5, f"Solver finished too quickly ({elapsed_time}s), timeout may not be working"
+
+    # Should have some solutions but not all (14-queens has 365,596 solutions)
+    assert res.num_solutions > 0, "Should have found at least some solutions before timeout"
+    assert res.num_solutions < 100000, f"Found {res.num_solutions} solutions - solver may not have timed out properly"
+
+    print(f"Timeout test passed: solver stopped after {elapsed_time:.2f}s (timeout was 2s)")
+
+
+@pytest.mark.asyncio
+async def test_no_timeout_completes():
+    """Test that without timeout, a simple problem completes successfully"""
+    problem = ConstraintModel(
+        model="var 1..10: x; solve satisfy;",
+        solver="gecode",
+        timeout=None,  # No timeout
+    )
+
+    res = await solve_constraint_core(problem)
+    assert res.status != "ERROR"
+    assert res.num_solutions >= 1