3 files changed, 24 insertions, 12 deletions
diff --git a/excelize_test.go b/excelize_test.go
index 8ee8051..f839136 100644
--- a/excelize_test.go
+++ b/excelize_test.go
@@ -220,6 +220,22 @@ func TestOpenReader(t *testing.T) {
 
 	_, err = OpenReader(r)
 	assert.EqualError(t, err, "unexpected EOF")
+
+	_, err = OpenReader(bytes.NewReader([]byte{
+		0x50, 0x4b, 0x03, 0x04, 0x0a, 0x00, 0x09, 0x00, 0x63, 0x00, 0x47, 0xa3, 0xb6, 0x50, 0x00, 0x00,
+		0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x0b, 0x00, 0x70, 0x61,
+		0x73, 0x73, 0x77, 0x6f, 0x72, 0x64, 0x01, 0x99, 0x07, 0x00, 0x02, 0x00, 0x41, 0x45, 0x03, 0x00,
+		0x00, 0x21, 0x06, 0x59, 0xc0, 0x12, 0xf3, 0x19, 0xc7, 0x51, 0xd1, 0xc9, 0x31, 0xcb, 0xcc, 0x8a,
+		0xe1, 0x44, 0xe1, 0x56, 0x20, 0x24, 0x1f, 0xba, 0x09, 0xda, 0x53, 0xd5, 0xef, 0x50, 0x4b, 0x07,
+		0x08, 0x00, 0x00, 0x00, 0x00, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x50, 0x4b, 0x01,
+		0x02, 0x1f, 0x00, 0x0a, 0x00, 0x09, 0x00, 0x63, 0x00, 0x47, 0xa3, 0xb6, 0x50, 0x00, 0x00, 0x00,
+		0x00, 0x1c, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x0b, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x70, 0x61, 0x73, 0x73, 0x77,
+		0x6f, 0x72, 0x64, 0x01, 0x99, 0x07, 0x00, 0x02, 0x00, 0x41, 0x45, 0x03, 0x00, 0x00, 0x50, 0x4b,
+		0x05, 0x06, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x41, 0x00, 0x00, 0x00, 0x5d, 0x00,
+		0x00, 0x00, 0x00, 0x00,
+	}))
+	assert.EqualError(t, err, "zip: unsupported compression algorithm")
 }
 
 func TestBrokenFile(t *testing.T) {
diff --git a/lib.go b/lib.go
index 5b7e6d0..91b3635 100644
--- a/lib.go
+++ b/lib.go
@@ -15,7 +15,6 @@ import (
 	"container/list"
 	"fmt"
 	"io"
-	"log"
 	"strconv"
 	"strings"
 	"unsafe"
@@ -59,7 +58,6 @@ func (f *File) saveFileList(name string, content []byte) {
 func readFile(file *zip.File) ([]byte, error) {
 	rc, err := file.Open()
 	if err != nil {
-		log.Println(err)
 		return nil, err
 	}
 	dat := make([]byte, 0, file.FileInfo().Size())
@@ -176,11 +174,7 @@ func CellNameToCoordinates(cell string) (int, int, error) {
 	}
 
 	col, err := ColumnNameToNumber(colname)
-	if err != nil {
-		return -1, -1, fmt.Errorf(msg, cell, err)
-	}
-
-	return col, row, nil
+	return col, row, err
 }
 
 // CoordinatesToCellName converts [X, Y] coordinates to alpha-numeric cell
@@ -195,11 +189,7 @@ func CoordinatesToCellName(col, row int) (string, error) {
 		return "", fmt.Errorf("invalid cell coordinates [%d, %d]", col, row)
 	}
 	colname, err := ColumnNumberToName(col)
-	if err != nil {
-		// Error should never happens here.
-		return "", fmt.Errorf("invalid cell coordinates [%d, %d]: %v", col, row, err)
-	}
-	return fmt.Sprintf("%s%d", colname, row), nil
+	return fmt.Sprintf("%s%d", colname, row), err
 }
 
 // boolPtr returns a pointer to a bool with the given value.
diff --git a/lib_test.go b/lib_test.go
index 4605e70..0e717b2 100644
--- a/lib_test.go
+++ b/lib_test.go
@@ -208,3 +208,9 @@ func TestBytesReplace(t *testing.T) {
 	s := []byte{0x01}
 	assert.EqualValues(t, s, bytesReplace(s, []byte{}, []byte{}, 0))
 }
+
+func TestStack(t *testing.T) {
+	s := NewStack()
+	assert.Equal(t, s.Peek(), nil)
+	assert.Equal(t, s.Pop(), nil)
+}