Refactor Sudoku field and solver implementation

logic/strategies/strategies_test.go

@@ -0,0 +1,82 @@
+package strategies
+
+import (
+	"strings"
+	"testing"
+
+	"git.kleiax.de/homepage/field"
+)
+
+const solvedGrid = "123456789456789123789123456234567891567891234891234567345678912678912345912345678"
+
+func strategyField(t *testing.T, digits string) *field.Field {
+	t.Helper()
+	props := field.Properties{Rows: 9, Columns: 9, BlockRows: 3, BlockColumns: 3, BlockSizeRow: 3, BlockSizeColumn: 3}
+	cells := make([][]field.Cell, 9)
+	for row := range cells {
+		cells[row] = make([]field.Cell, 9)
+		for column := range cells[row] {
+			pos := field.NewPosition(row, column, row/3, column/3, row%3, column%3)
+			cells[row][column] = *field.NewCell(int(digits[row*9+column]-'0'), pos)
+		}
+	}
+	result, err := field.New(props, cells)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return result
+}
+
+func TestLastDigitDeduplicatesOverlappingParts(t *testing.T) {
+	f := strategyField(t, "0"+solvedGrid[1:])
+	strategy := &LastDigit{}
+	strategy.Init(f)
+	if got := strategy.SearchProgressableCells(); got != 1 {
+		t.Fatalf("SearchProgressableCells() = %d, want 1", got)
+	}
+	changes, err := strategy.ApplyAll()
+	if err != nil {
+		t.Fatalf("ApplyAll() error = %v", err)
+	}
+	if len(changes) != 1 || !f.IsSolved() {
+		t.Fatalf("changes = %d, solved = %v", len(changes), f.IsSolved())
+	}
+}
+
+func TestHiddenSingleUsesCandidateValuesNotSliceIndexes(t *testing.T) {
+	f := strategyField(t, strings.Repeat("0", 81))
+	first, _ := f.GetCell(0, 0)
+	second, _ := f.GetCell(0, 1)
+	third, _ := f.GetCell(0, 2)
+	for _, setup := range []struct {
+		cell *field.Cell
+		note int
+	}{{first, 9}, {second, 8}, {third, 8}} {
+		if err := setup.cell.GetNotes().Add(f, setup.cell, setup.note, "test", nil); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	strategy := &HiddenSingle{}
+	strategy.Init(f)
+	strategy.SearchProgressableCells()
+	found := false
+	for _, change := range strategy.changes {
+		if change.Cell == first && change.Value == 9 {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatal("hidden single for candidate value 9 was not found")
+	}
+}
+
+func TestIntersection3IsSorted(t *testing.T) {
+	got := intersection3([]int{9, 1, 5}, []int{5, 9, 1}, []int{9, 5, 1})
+	want := []int{1, 5, 9}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Fatalf("intersection3() = %v, want %v", got, want)
+		}
+	}
+}