proejct commit

tests/helpers.py

@@ -0,0 +1,81 @@
+"""Hilfsfunktionen für die Physik-Tests (Szenen aufbauen, simulieren, Erhaltungsgrößen)."""
+
+from __future__ import annotations
+
+from dataclasses import replace
+
+from sandbox.config import PHYSICS, TIME_STEP
+from sandbox.physics import Body, Material, Vector2, World
+
+WORLD_WIDTH = 1000.0
+WORLD_HEIGHT = 700.0
+
+
+def make_world(
+    width: float = WORLD_WIDTH, height: float = WORLD_HEIGHT, **overrides: object
+) -> World:
+    """Welt mit Standardkonfiguration; einzelne Parameter lassen sich überschreiben."""
+    return World(width, height, replace(PHYSICS, **overrides))
+
+
+def material(density: float = 1.0, restitution: float = 0.5, friction: float = 0.5) -> Material:
+    """Material mit gut lesbaren Standardwerten."""
+    return Material(density=density, restitution=restitution, friction=friction)
+
+
+def add_circle(
+    world: World,
+    x: float,
+    y: float,
+    radius: float,
+    *,
+    velocity: tuple[float, float] = (0.0, 0.0),
+    angular_velocity: float = 0.0,
+    **material_values: float,
+) -> Body:
+    """Fügt einen Kreis hinzu."""
+    body = Body.circle(
+        Vector2(x, y), radius, material(**material_values), velocity=Vector2(*velocity)
+    )
+    body.angular_velocity = angular_velocity
+    return world.add_body(body)
+
+
+def add_box(
+    world: World,
+    x: float,
+    y: float,
+    half_width: float,
+    half_height: float,
+    *,
+    velocity: tuple[float, float] = (0.0, 0.0),
+    **material_values: float,
+) -> Body:
+    """Fügt ein achsenparalleles Rechteck hinzu."""
+    body = Body.box(
+        Vector2(x, y),
+        half_width,
+        half_height,
+        material(**material_values),
+        velocity=Vector2(*velocity),
+    )
+    return world.add_body(body)
+
+
+def simulate(world: World, seconds: float, dt: float = TIME_STEP) -> None:
+    """Führt so viele feste Schritte aus, wie in ``seconds`` passen."""
+    for _ in range(round(seconds / dt)):
+        world.step(dt)
+
+
+def total_momentum(bodies: list[Body]) -> Vector2:
+    """Summe der Impulse m·v."""
+    total = Vector2()
+    for body in bodies:
+        total = total + body.momentum()
+    return total
+
+
+def total_kinetic_energy(bodies: list[Body]) -> float:
+    """Summe der Bewegungsenergien (translatorisch + rotatorisch)."""
+    return sum(body.kinetic_energy() for body in bodies)