Castle Wall Hazard Map (#101)

* castle_wall map

Wall of hazards around the board with dangerous bridges.

- add support for all standard board sizes
- hazard placement for all board sizes

* passage food placement for all board sizes

* 4 snake starting positions for all maps

* only one food can spawn on a bridge

* support 8 snakes for all board sizes

support 12 snakes on XLarge and XXLarge board sizes

* max 2 food sm/med/lg and max 4 food on xlg/xxlg

no food in the first 10 turns

* sort generated hazard positions

* remove 'uninteresting' castle wall map board sizes

* refactor castle wall map to align with #103

* align map castle wall meta Name with ID

* set MinPlayers to 1 for castle wall map

* pass max snake/food and startPosition to priv func

* fix castle wall food placement and refactor tests

* avoid food spawn by snake heads on castle wall map

- fixes forced food spawning infront of snake issue on large & xlarge maps with double walls

maps/castle_wall_internal_test.go

@@ -0,0 +1,67 @@
+package maps
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/BattlesnakeOfficial/rules"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCastleWallMaps(t *testing.T) {
+
+	tests := []struct {
+		gameMap        GameMap
+		startPositions [][]rules.Point
+	}{
+		{
+			gameMap:        CastleWallMediumHazardsMap{},
+			startPositions: castleWallMediumStartPositions,
+		},
+		{
+			gameMap:        CastleWallLargeHazardsMap{},
+			startPositions: castleWallLargeStartPositions,
+		},
+		{
+			gameMap:        CastleWallExtraLargeHazardsMap{},
+			startPositions: castleWallExtraLargeStartPositions,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.gameMap.ID(), func(t *testing.T) {
+			m := test.gameMap
+			settings := rules.Settings{}
+			sizes := test.gameMap.Meta().BoardSizes
+			for _, s := range sizes {
+				initialState := rules.NewBoardState(int(s.Width), int(s.Height))
+				startPositions := test.startPositions
+				for i := 0; i < int(test.gameMap.Meta().MaxPlayers); i++ {
+					initialState.Snakes = append(initialState.Snakes, rules.Snake{ID: fmt.Sprint(i), Body: []rules.Point{}})
+				}
+				nextState := rules.NewBoardState(int(s.Width), int(s.Height))
+				editor := NewBoardStateEditor(nextState)
+				err := m.SetupBoard(initialState, settings, editor)
+				require.NoError(t, err)
+				for _, s := range nextState.Snakes {
+					require.Len(t, s.Body, rules.SnakeStartSize, "Placed snakes should have the right length")
+					require.Equal(t, s.Health, rules.SnakeMaxHealth, "Placed snakes should have the right health")
+					require.NotEmpty(t, s.ID, "Snake ID shouldn't be empty (should get copied when placed)")
+
+					// Check that the snake is placed at one of the specified start positions
+					validStart := false
+					for _, q := range startPositions {
+						for i := 0; i < len(q); i++ {
+							if q[i].X == s.Body[0].X && q[i].Y == s.Body[0].Y {
+								validStart = true
+								break
+							}
+						}
+					}
+					require.True(t, validStart, "Snake must be placed in one of the specified start positions")
+				}
+			}
+		})
+	}
+}