Merge pull request #11 from xiegeo/go

Check for sudoku rules using ci and go

.travis.yml

@@ -0,0 +1,6 @@
+language: go
+
+go:
+  - "1.x"
+
+

sudoku_test.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"os"
+	"regexp"
+	"testing"
+)
+
+type Used [9]bool
+
+func (u *Used) Add(n int) error {
+	n-- //change from 1 to 9 in sudoku to 0 to 8 for indexing
+	if u[n] {
+		return errors.New("number is used")
+	}
+	u[n] = true
+	return nil
+}
+
+func TestSudoku(t *testing.T) {
+	f, err := os.Open("README.md")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+	r := bufio.NewReader(f)
+	skipLines(r, 10)
+	var rs, cs, bs [9]Used
+	for i := 0; i < 9; i++ {
+		for j := 0; j < 9; j++ {
+			t.Run(fmt.Sprintf("line %v%v", i+1, j+1), func(t *testing.T) {
+				n, err := nextNumber(r)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if n == 0 {
+					return
+				}
+				err = rs[i].Add(n)
+				if err != nil {
+					t.Fatal(err)
+				}
+				err = cs[j].Add(n)
+				if err != nil {
+					t.Fatal(err)
+				}
+				k := i/3 + (j/3)*3
+				err = bs[k].Add(n)
+				if err != nil {
+					t.Fatal(err)
+				}
+			})
+		}
+		skipLines(r, 1)
+	}
+}
+
+var numberRegexp = regexp.MustCompile(`[1-9]`)
+var spaceRegexp = regexp.MustCompile(`&nbsp;`)
+
+func nextNumber(r *bufio.Reader) (int, error) {
+	line, pre, err := r.ReadLine()
+	if err != nil {
+		return 0, err
+	}
+	if pre {
+		return 0, errors.New("unhandled pre")
+	}
+	numbers := numberRegexp.FindAll(line, -1)
+	if len(numbers) > 1 {
+		return 0, errors.New("too many digits")
+	}
+	if len(numbers) == 1 {
+		return int(numbers[0][0] - '0'), nil
+	}
+	space := spaceRegexp.Find(line)
+	if space == nil {
+		return 0, errors.New("expected space filler for empty cells")
+	}
+	return 0, nil
+}
+
+func skipLines(r *bufio.Reader, n int) error {
+	for i := 0; i < n; i++ {
+		_, pre, err := r.ReadLine()
+		if err != nil {
+			return err
+		}
+		if pre {
+			i--
+		}
+	}
+	return nil
+}