Add fuzz testing for waypoint solvers.

This fuzz test generates random inputs for waypoint solvers to check if
they can find a solution. If they can't, the debug info for the solver
is dumped to the testcases directory. Another test loads those test
cases, creates a solver from them, and checks that a solution is found.
Obviously it won't be immediately, but it's a starting point for fixing
the bug and serves as a regression test afterward.

tests/flightplan/test_waypointsolverloader.py

@@ -0,0 +1,54 @@
+import json
+from pathlib import Path
+
+import pytest
+
+from game.flightplan.ipsolver import IpSolver
+from game.flightplan.waypointsolverloader import WaypointSolverLoader
+
+
+def test_waypointsolverloader(tmp_path: Path) -> None:
+    debug_info_path = tmp_path / "solver.json"
+    debug_info_path.write_text(
+        json.dumps(
+            {
+                "type": "FeatureCollection",
+                "metadata": {
+                    "name": "IpSolver",
+                    "terrain": "Falklands",
+                    "doctrine": "coldwar",
+                },
+                "features": [
+                    {
+                        "type": "Feature",
+                        "properties": {"description": "departure"},
+                        "geometry": {
+                            "type": "Point",
+                            "coordinates": [-59.17351849883801, -52.46892777233296],
+                        },
+                    },
+                    {
+                        "type": "Feature",
+                        "properties": {"description": "target"},
+                        "geometry": {
+                            "type": "Point",
+                            "coordinates": [-59.12970828579045, -52.51860490233211],
+                        },
+                    },
+                    {
+                        "type": "Feature",
+                        "properties": {"description": "threat_zones"},
+                        "geometry": {"type": "MultiPolygon", "coordinates": []},
+                    },
+                ],
+            }
+        )
+    )
+    solver = WaypointSolverLoader(debug_info_path).load()
+    assert isinstance(solver, IpSolver)
+    assert solver.doctrine.name == "coldwar"
+    assert solver.threat_zones.is_empty
+    assert solver.departure.x == pytest.approx(0, abs=1e-8)
+    assert solver.departure.y == pytest.approx(0, abs=1e-8)
+    assert solver.target.x == pytest.approx(-5436.058, abs=0.001)
+    assert solver.target.y == pytest.approx(3138.51, abs=0.001)