Add boardIsValid checker function

pkg/board/board_test.go

@@ -1,7 +1,6 @@
 package board
 
 import (
-	"fmt"
 	"reflect"
 	"testing"
 )
@@ -56,13 +55,29 @@ func TestFindLowestEntropyTiles(t *testing.T) {
 	}
 }
 
-// TODO
 func TestSolveOneStep(t *testing.T) {
 	board := New()
-	solveOneStep(&board)
-	solveOneStep(&board)
-	solveOneStep(&board)
+	numSolvedAtStart := 1 // TODO change when revisiting board initialisation
+	for i := 0; i < NumValues-numSolvedAtStart; i++ {
+		solveOneStep(&board)
+	}
+
+	isValid, message := boardIsValid(board)
+	if !isValid {
+		t.Errorf("Expected board to be valid, got invalid with message %v", message)
+	}
+}
 
-	// is random /really/ random?
-	fmt.Println(board)
+func TestBoardIsValid(t *testing.T) {
+	board := New()
+	isValid, message := boardIsValid(board)
+	if !isValid {
+		t.Errorf("Expected starting board to be valid, got invalid with message %v", message)
+	}
+
+	board.GetTile(0, 1).value = 1
+	isValid, message = boardIsValid(board)
+	if isValid {
+		t.Errorf("Expected modified board to be invalid, got valid with message %v", message)
+	}
 }

pkg/board/utils.go

@@ -1,30 +1,59 @@
 package board
 
 import (
+	"fmt"
 	"math/rand"
-	"time"
 )
 
-func solveOneStep(board *Board) {
-	// panic("TODO: implement")
-
-	// 1. get slice of lowest entropy tiles
-	// 2. for each tile, get possible values
-	// 3. if only one possible value, set the value
-	// 4. if no possible value, return error
-	// 5. select random tile from lowest entropy tiles
-	// 6. select random value from possible values
-	// 7. set the value
-	// 8. ???
-	// 9. profit
+func boardIsValid(board Board) (isValid bool, message string) {
+	// check columns are unique
+	for x := 0; x < BoardSize; x++ {
+		col := board.GetCol(x)
+		seenColValues := make(map[int]bool)
+
+		for y := 0; y < BoardSize; y++ {
+			val := col[y].value
+			if val == Empty {
+				continue
+			}
+
+			if seenColValues[val] {
+				return false, fmt.Sprint("Val is not unique in col", val)
+			}
+
+			seenColValues[val] = true
+		}
+	}
+
+	// check rows are unique
+	for y := 0; y < BoardSize; y++ {
+		row := board.GetRow(y)
+		seenRowValues := make(map[int]bool)
+
+		for x := 0; x < BoardSize; x++ {
+			val := row[x].value
+			if val == Empty {
+				continue
+			}
 
+			if seenRowValues[val] {
+				return false, fmt.Sprint("Val is not unique in row", val)
+			}
+
+			seenRowValues[val] = true
+		}
+	}
+
+	return true, "Board is valid"
+}
+
+func solveOneStep(board *Board) {
 	lowestEntropyTiles := board.findLowestEntropyTiles()
 
 	if len(lowestEntropyTiles) == 0 {
 		panic("No solution found. TODO backgrack")
 	}
 
-	rand.Seed(time.Now().Unix())
 	randomTileIndex := rand.Intn(len(lowestEntropyTiles))
 	randomTile := lowestEntropyTiles[randomTileIndex]
 	randomValueIndex := rand.Intn(len(randomTile.possibleValues))