add phys.apply

asteroids/test_phys.lua

@@ -0,0 +1,33 @@
+t = require('luaunit')
+local phys = require('phys')
+
+function TestUpdate()
+    local actor = { x = 0, y = 0, speed = 1, angle = math.pi }
+    phys.update(actor, 0.1)
+    t.assertAlmostEquals(
+        actor,
+        { x = -0.1, y = 0, speed = 1, angle = math.pi })
+end
+
+function TestApply()
+    local actor = { x = 0, y = 0, speed = 1, angle = math.pi }
+
+    phys.apply(actor, { speed = 1, angle = 0 })
+    t.assertAlmostEquals(
+        { x = actor.x, y = actor.y, speed = actor.speed },
+        { x = 0, y = 0, speed = 0 })
+
+    phys.apply(actor, { speed = 1, angle = math.pi })
+    t.assertAlmostEquals(
+        actor,
+        { x = 0, y = 0, speed = 1, angle = math.pi }
+    )
+
+    phys.apply(actor, { speed = 1, angle = math.pi / 2 })
+    t.assertAlmostEquals(
+        actor,
+        { x = 0, y = 0, speed = math.sqrt(2), angle = math.pi * 3 / 4 }
+    )
+end
+
+os.exit(t.LuaUnit.run())