Refactor Sudoku field and solver implementation

logic/solver_test.go

@@ -0,0 +1,71 @@
+package logic_test
+
+import (
+	"errors"
+	"testing"
+
+	"git.kleiax.de/homepage/field"
+	"git.kleiax.de/homepage/logic"
+	"git.kleiax.de/homepage/logic/strategies"
+	"git.kleiax.de/homepage/parser"
+)
+
+const solvedPuzzle = "123456789456789123789123456234567891567891234891234567345678912678912345912345678"
+
+func parsedField(t *testing.T, puzzle string) *field.Field {
+	t.Helper()
+	input := &parser.PuzzleString{}
+	if err := input.Parse([]byte(puzzle)); err != nil {
+		t.Fatal(err)
+	}
+	result, err := input.GetField(0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return result
+}
+
+func TestSolverRunSolvesAndDetectsNoProgress(t *testing.T) {
+	t.Run("solved", func(t *testing.T) {
+		f := parsedField(t, "0"+solvedPuzzle[1:])
+		solver := &logic.Solver{}
+		solver.Add(&strategies.LastDigit{})
+		if err := solver.InitStrategies(f); err != nil {
+			t.Fatal(err)
+		}
+		solved, err := solver.Run(0)
+		if err != nil || !solved || !f.IsSolved() {
+			t.Fatalf("Run() = (%v, %v), field solved = %v", solved, err, f.IsSolved())
+		}
+	})
+
+	t.Run("no progress", func(t *testing.T) {
+		f := parsedField(t, "0"+solvedPuzzle[1:])
+		solver := &logic.Solver{}
+		if err := solver.InitStrategies(f); err != nil {
+			t.Fatal(err)
+		}
+		solved, err := solver.Run(0)
+		if err != nil || solved {
+			t.Fatalf("Run() = (%v, %v), want (false, nil)", solved, err)
+		}
+	})
+}
+
+func TestSolverRejectsInvalidStateAndStrategyIndex(t *testing.T) {
+	solver := &logic.Solver{}
+	if _, err := solver.Run(0); !errors.Is(err, field.ErrInvalidField) {
+		t.Fatalf("Run() before initialization error = %v", err)
+	}
+	if err := solver.InitStrategies(nil); !errors.Is(err, field.ErrInvalidField) {
+		t.Fatalf("InitStrategies(nil) error = %v", err)
+	}
+
+	f := parsedField(t, "0"+solvedPuzzle[1:])
+	if err := solver.InitStrategies(f); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := solver.Run(1); err == nil {
+		t.Fatal("Run() with invalid strategy index error = nil")
+	}
+}