feat(scala): m01–m06 port with shared fixtures

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

scala/test/M02Model.test.scala

@@ -0,0 +1,54 @@
+package snake
+
+import Fixtures.*
+
+class M02ModelSuite extends munit.FunSuite:
+  cases("m02-delta").foreach { c =>
+    test(s"delta: ${c("name").str}") {
+      assertEquals(Model.delta(direction(c("args")(0))), point(c("expected")))
+    }
+  }
+
+  cases("m02-opposite").foreach { c =>
+    test(s"opposite: ${c("name").str}") {
+      assertEquals(Model.opposite(direction(c("args")(0))), direction(c("expected")))
+    }
+  }
+
+  // pointEquals has no Scala function: case classes already compare structurally with `==`.
+  // The shared fixture is kept so every track checks the same four situations.
+  cases("m02-point-equals").foreach { c =>
+    test(s"pointEquals (case-class ==): ${c("name").str}") {
+      val a = point(c("args")(0))
+      val b = point(c("args")(1))
+      assertEquals(a == b, c("expected").bool)
+    }
+  }
+
+  cases("m02-initial-state").foreach { c =>
+    test(s"initialState: ${c("name").str}") {
+      assertEquals(Model.initialState(c("args")(0).num.toLong), gameState(c("expected")))
+    }
+  }
+
+  test("Point holds its coordinates") {
+    val p = Point(3, 4)
+    assertEquals((p.x, p.y), (3, 4))
+  }
+
+  test("opposite is its own inverse") {
+    Direction.values.foreach(d => assertEquals(Model.opposite(Model.opposite(d)), d))
+  }
+
+  test("Action.Turn carries the direction") {
+    assertEquals(Action.Turn(Direction.Left), Action.Turn(Direction.Left))
+    assertNotEquals(Action.Turn(Direction.Left), Action.Turn(Direction.Right))
+    Action.Turn(Direction.Left) match
+      case Action.Turn(d) => assertEquals(d, Direction.Left)
+      case other          => fail(s"expected Turn, got $other")
+  }
+
+  test("the other Actions are distinct constants") {
+    val all = List(Action.Tick, Action.TogglePause, Action.Restart, Action.Frame)
+    assertEquals(all.distinct.length, 4)
+  }