From cf2fc3b0151863d520a1437da4396b88fc7091e0 Mon Sep 17 00:00:00 2001
From: George Xie <george@xiegeo.com>
Date: Sat, 14 Apr 2018 16:17:03 -0700
Subject: [PATCH 1/3] write the tests

---
 sudoku_test.go | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 sudoku_test.go

diff --git a/sudoku_test.go b/sudoku_test.go
new file mode 100644
index 0000000..3871503
--- /dev/null
+++ b/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 numbers")
+	}
+	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
+}

From c2a445258c0505901ad6ec42f3da32ad80871449 Mon Sep 17 00:00:00 2001
From: George Xie <george@xiegeo.com>
Date: Sat, 14 Apr 2018 16:24:02 -0700
Subject: [PATCH 2/3] clarify error message

---
 sudoku_test.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sudoku_test.go b/sudoku_test.go
index 3871503..bb5e0a9 100644
--- a/sudoku_test.go
+++ b/sudoku_test.go
@@ -71,7 +71,7 @@ func nextNumber(r *bufio.Reader) (int, error) {
 	}
 	numbers := numberRegexp.FindAll(line, -1)
 	if len(numbers) > 1 {
-		return 0, errors.New("too many numbers")
+		return 0, errors.New("too many digits")
 	}
 	if len(numbers) == 1 {
 		return int(numbers[0][0] - '0'), nil

From bafa32076db8339ac70172b95cbbeb4d5a43e46a Mon Sep 17 00:00:00 2001
From: George Xie <george@xiegeo.com>
Date: Sat, 14 Apr 2018 16:30:21 -0700
Subject: [PATCH 3/3] add travis ci

---
 .travis.yml | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 .travis.yml

diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..9046ef8
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,6 @@
+language: go
+
+go:
+  - "1.x"
+
+  
\ No newline at end of file