(finally!) doing some TDD in Go

conway/go/conway_test.go

@@ -1,16 +1,73 @@
 package conway_test
 
 import (
-    "testing"
+	"testing"
 )
 
 import (
-    . "github.com/meatballhat/box-o-sand/conway/go"
+	. "github.com/meatballhat/box-o-sand/conway/go"
 )
 
-func TestNewGameOfLifeIsNonEmpty(t *testing.T) {
-    game := NewGameOfLife()
-    if game.Height < 1 || game.Width < 1 {
-        t.Fail()
-    }
+var TEST_SIMPLE_INITIAL_STATE = NewGameState(16, 16)
+
+func init() {
+	tsis := TEST_SIMPLE_INITIAL_STATE
+	tsis.Set(0, 0, 1)
+	tsis.Set(1, 0, 1)
+	tsis.Set(0, 1, 1)
+	tsis.Set(1, 1, 1)
+}
+
+func TestNewGameOfLifeHasCorrectDimensions(t *testing.T) {
+	game := NewGameOfLife(16, 16)
+	if game.Height != 16 || game.Width != 16 {
+		t.Fail()
+	}
+}
+
+func TestLiveCellWithFewerThanTwoLiveNeighborsDies(t *testing.T) {
+	state := NewGameState(16, 16)
+	state.ImportState(TEST_SIMPLE_INITIAL_STATE)
+}
+
+func TestNewGameStatesAreAllDead(t *testing.T) {
+	state := NewGameState(4, 4)
+	for x := 0; x < 3; x++ {
+		for y := 0; y < 3; y++ {
+			if state.Rows[y].Cols[x] != 0 {
+				t.Fail()
+			}
+		}
+	}
+}
+
+func TestGameStateCanEnlivenCellsByCoords(t *testing.T) {
+	state := NewGameState(8, 8)
+	if err := state.Enliven(0, 1); err != nil {
+		t.Fail()
+	}
+
+	if state.Rows[1].Cols[0] != 1 {
+		t.Fail()
+	}
+}
+
+func TestGameStateCanDeadenCellsByCoords(t *testing.T) {
+	state := NewGameState(8, 8)
+
+	if err := state.Enliven(0, 1); err != nil {
+		t.Fail()
+	}
+
+	if state.Rows[1].Cols[0] != 1 {
+		t.Fail()
+	}
+
+	if err := state.Deaden(0, 1); err != nil {
+		t.Fail()
+	}
+
+	if state.Rows[1].Cols[0] != 0 {
+		t.Fail()
+	}
 }

conway/go/game_of_life.go

@@ -1,13 +1,91 @@
 package conway
 
+import (
+	"errors"
+)
+
 type GameOfLife struct {
-	Height uint8
-	Width  uint8
+	Height int
+	Width  int
 }
 
-func NewGameOfLife() *GameOfLife {
+type GameGridRow struct {
+	Cols []int
+}
+
+type GameState struct {
+	Rows []*GameGridRow
+}
+
+func NewGameState(height, width int) *GameState {
+	state := &GameState{}
+	for i := 0; i < height; i++ {
+		row := &GameGridRow{}
+		for j := 0; j < width; j++ {
+			row.Cols = append(row.Cols, 0)
+		}
+		state.Rows = append(state.Rows, row)
+	}
+	return state
+}
+
+func (state *GameState) GetRow(y int) (*GameGridRow, error) {
+	if len(state.Rows) < y+1 {
+		return nil, errors.New("y coordinate is out of bounds!")
+	}
+
+	return state.Rows[y], nil
+}
+
+func (state *GameState) Set(x, y, value int) error {
+	row, err := state.GetRow(y)
+	if err != nil {
+		return err
+	}
+
+	if len(row.Cols) < x+1 {
+		return errors.New("x coordinate is out of bounds!")
+	}
+
+	row.Cols[x] = value
+	return nil
+}
+
+func (state *GameState) Get(x, y int) (int, error) {
+	row, err := state.GetRow(y)
+	if err != nil {
+		return -1, err
+	}
+
+	if len(row.Cols) < x+1 {
+		return -1, errors.New("x coordinate is out of bounds!")
+	}
+
+	return row.Cols[x], nil
+}
+
+func (state *GameState) Enliven(x, y int) error {
+	return state.Set(x, y, 1)
+}
+
+func (state *GameState) Deaden(x, y int) error {
+	return state.Set(x, y, 0)
+}
+
+func NewGameOfLife(height, width int) *GameOfLife {
 	return &GameOfLife{
-		Height: 16,
-		Width:  16,
+		Height: height,
+		Width:  width,
 	}
 }
+
+func (state *GameState) ImportState(other *GameState) (err error) {
+	for y, row := range other.Rows {
+		for x, cell := range row.Cols {
+			if err = state.Set(x, y, cell); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}