diff --git a/.gitignore b/.gitignore
index 7e82ee290c..ce92812619 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,9 @@
 ~$*.xlsx
 test/Test*.xlsx
 test/Test*.xlsm
+# generated files
+test/BadEncrypt.xlsx
+test/BadWorkbook.SaveAsEmptyStruct.xlsx
 test/*.png
 *.out
 *.test
diff --git a/cell.go b/cell.go
index c797974764..22adefd454 100644
--- a/cell.go
+++ b/cell.go
@@ -766,11 +766,11 @@ func (f *File) formattedValue(s int, v string) string {
 	if s >= len(styleSheet.CellXfs.Xf) {
 		return v
 	}
-	if styleSheet.CellXfs.Xf[s].NumFmtID == nil {
-		return v
+	var numFmtID int
+	if styleSheet.CellXfs.Xf[s].NumFmtID != nil {
+		numFmtID = *styleSheet.CellXfs.Xf[s].NumFmtID
 	}
 
-	numFmtID := *styleSheet.CellXfs.Xf[s].NumFmtID
 	ok := builtInNumFmtFunc[numFmtID]
 	if ok != nil {
 		return ok(v, builtInNumFmt[numFmtID])
diff --git a/cell_test.go b/cell_test.go
index 23c8474ddb..8d3f77482d 100644
--- a/cell_test.go
+++ b/cell_test.go
@@ -301,7 +301,7 @@ func TestSetCellRichText(t *testing.T) {
 	assert.EqualError(t, f.SetCellRichText("Sheet1", "A", richTextRun), `cannot convert cell "A" to coordinates: invalid cell name "A"`)
 }
 
-func TestFormattedValue(t *testing.T) {
+func TestFormattedValue2(t *testing.T) {
 	f := NewFile()
 	v := f.formattedValue(0, "43528")
 	assert.Equal(t, "43528", v)
@@ -320,7 +320,6 @@ func TestFormattedValue(t *testing.T) {
 	assert.Equal(t, "03/04/2019", v)
 
 	// formatted value with no built-in number format ID
-	assert.NoError(t, err)
 	numFmtID := 5
 	f.Styles.CellXfs.Xf = append(f.Styles.CellXfs.Xf, xlsxXf{
 		NumFmtID: &numFmtID,
@@ -329,31 +328,16 @@ func TestFormattedValue(t *testing.T) {
 	assert.Equal(t, "43528", v)
 
 	// formatted value with invalid number format ID
-	assert.NoError(t, err)
 	f.Styles.CellXfs.Xf = append(f.Styles.CellXfs.Xf, xlsxXf{
 		NumFmtID: nil,
 	})
 	v = f.formattedValue(3, "43528")
-	assert.Equal(t, "43528", v)
-}
-func TestInvalidNumberFormatsLoad(t *testing.T) {
-	f, err := OpenFile(filepath.Join("test", "Items.xlsx"))
-	assert.NoError(t, err)
-
-	rows, err := f.Rows("Sheet 1")
-	assert.NoError(t, err)
-
-	var rowCount int
-	for rows.Next() {
-		rowCount++
-		row, err := rows.Columns()
-		assert.NoError(t, err)
 
-		if rowCount > 1 {
-			assert.Equal(t, "0.5", row[13])
-			assert.Equal(t, "12/08/2020", row[14])
-		}
-	}
-
-	assert.Equal(t, 20, rowCount)
+	// formatted value with empty number format
+	f.Styles.NumFmts = nil
+	f.Styles.CellXfs.Xf = append(f.Styles.CellXfs.Xf, xlsxXf{
+		NumFmtID: &numFmtID,
+	})
+	v = f.formattedValue(1, "43528")
+	assert.Equal(t, "43528", v)
 }
diff --git a/crypt_test.go b/crypt_test.go
index d98b97b577..6f712c1944 100644
--- a/crypt_test.go
+++ b/crypt_test.go
@@ -19,7 +19,7 @@ import (
 func TestEncrypt(t *testing.T) {
 	f, err := OpenFile(filepath.Join("test", "encryptSHA1.xlsx"), Options{Password: "password"})
 	assert.NoError(t, err)
-	assert.EqualError(t, f.SaveAs(filepath.Join("test", "TestBadEncrypt.xlsx"), Options{Password: "password"}), "not support encryption currently")
+	assert.EqualError(t, f.SaveAs(filepath.Join("test", "BadEncrypt.xlsx"), Options{Password: "password"}), "not support encryption currently")
 }
 
 func TestEncryptionMechanism(t *testing.T) {
diff --git a/excelize_test.go b/excelize_test.go
index 89e3749a6f..1b4887275b 100644
--- a/excelize_test.go
+++ b/excelize_test.go
@@ -257,7 +257,7 @@ func TestBrokenFile(t *testing.T) {
 
 	t.Run("SaveAsEmptyStruct", func(t *testing.T) {
 		// Test write file with broken file struct with given path.
-		assert.NoError(t, f.SaveAs(filepath.Join("test", "TestBadWorkbook.SaveAsEmptyStruct.xlsx")))
+		assert.NoError(t, f.SaveAs(filepath.Join("test", "BadWorkbook.SaveAsEmptyStruct.xlsx")))
 	})
 
 	t.Run("OpenBadWorkbook", func(t *testing.T) {
diff --git a/test/Items.xlsx b/test/Items.xlsx
deleted file mode 100644
index e2b233fb6d..0000000000
Binary files a/test/Items.xlsx and /dev/null differ