diff --git a/main.go b/main.go
index 415f834..d003709 100644
--- a/main.go
+++ b/main.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"errors"
 	"flag"
 	"io"
@@ -9,6 +10,8 @@ import (
 )
 
 var (
+	stdin            io.Reader = os.Stdin
+	stdout           io.Writer = os.Stdout
 	columnDelimiter  string
 	pageDelimiter    string
 	minimumInstances int
@@ -19,20 +22,26 @@ func main() {
 	flag.StringVar(&columnDelimiter, "d", " ", "column delimiter character")
 	flag.IntVar(&minimumInstances, "m", 2, "minimum non-leading instances of delimiter to break a column")
 	flag.Parse()
+	if err := _main(); err != nil {
+		panic(err)
+	}
+}
 
-	r := bufio.NewReader(os.Stdin)
+func _main() error {
+	r := bufio.NewReader(stdin)
 	for {
 		b, err := readPage(r)
 		if err != nil && err != io.EOF {
-			panic(err)
+			return err
 		}
 		if err := putPage(b); err != nil {
-			panic(err)
+			return err
 		}
 		if err == io.EOF {
 			break
 		}
 	}
+	return nil
 }
 
 func readPage(r *bufio.Reader) ([]byte, error) {
@@ -48,5 +57,16 @@ func _readPage(d byte, r *bufio.Reader) ([]byte, error) {
 }
 
 func putPage(b []byte) error {
+	return _putPage(stdout, b)
+}
+
+func _putPage(w io.Writer, b []byte) error {
+	for _, line := range lines(b) {
+		_ = line
+	}
 	return errors.New("not impl")
 }
+
+func lines(b []byte) [][]byte {
+	return bytes.Split(b, []byte{'\n'})
+}
diff --git a/main_test.go b/main_test.go
index 830ee27..2eadc87 100644
--- a/main_test.go
+++ b/main_test.go
@@ -2,12 +2,25 @@ package main
 
 import (
 	"bufio"
+	"bytes"
 	"fmt"
 	"io"
 	"strings"
 	"testing"
 )
 
+func Test_Main(t *testing.T) {
+	stdin = strings.NewReader("\ta a a\t\tb b b\na a\t\tb b\fc c\td d\nc c\td.")
+	stdout = bytes.NewBuffer(nil)
+	columnDelimiter = "\t"
+	pageDelimiter = "\f"
+	minimumInstances = 1
+	if err := _main(); err != nil {
+		t.Error(err)
+	}
+	t.Errorf("%s", stdout.(*bytes.Buffer).Bytes())
+}
+
 func TestReadPage(t *testing.T) {
 	cases := map[string]struct {
 		input string