fix: zero option

lib/shred/shred.go

@@ -43,25 +43,31 @@ func (s *Shredder) Write(pathName string) error {
 	// Stat the file for the file length
 	fstat, err := os.Stat(pathName)
 	if err != nil {
-		return fmt.Errorf("shredding failed: %w", err)
+		return fmt.Errorf("file stat failed: %w", err)
 	}
 
 	// Open the file
 	file, err := os.OpenFile(pathName, os.O_WRONLY, fstat.Mode())
 	if err != nil {
-		return fmt.Errorf("shredding failed: %w", err)
+		return fmt.Errorf("file opening failed: %w", err)
 	}
+	defer file.Close()
 
 	err = s.shred(fstat, file)
 	if err != nil {
 		return fmt.Errorf("shredding failed: %w", err)
 	}
 
+	if s.options.Zero {
+		if err := os.Truncate(pathName, 0); err != nil {
+			return fmt.Errorf("truncate failed: %w", err)
+		}
+	}
+
 	return nil
 }
 
 func (s *Shredder) shred(fstat FileInfo, file File) error {
-	defer file.Close()
 	fSize := fstat.Size()
 
 	// Avoid shredding if the file is already empty
@@ -102,12 +108,5 @@ func (s *Shredder) shred(fstat FileInfo, file File) error {
 		}
 	}
 
-	if s.options.Zero {
-		_, err := file.Write([]byte{})
-		if err != nil {
-			return err
-		}
-	}
-
 	return nil
 }

lib/shred/shred_test.go

@@ -18,12 +18,12 @@ func TestShredder_Write(t *testing.T) {
 		{
 			name:      "test with non-existing file",
 			input:     "testdata/fake.log",
-			wantError: errors.New("shredding failed: stat testdata/fake.log: no such file or directory"),
+			wantError: errors.New("file stat failed: stat testdata/fake.log: no such file or directory"),
 		},
 		{
 			name:      "test with non-file path",
 			input:     "testdata/",
-			wantError: errors.New("shredding failed: open testdata/: is a directory"),
+			wantError: errors.New("file opening failed: open testdata/: is a directory"),
 		},
 	}
 
@@ -57,7 +57,6 @@ func TestShredder_shred(t *testing.T) {
 			},
 			mocks: func(fakeFileInfo *mocks.FileInfo, fakeFile *mocks.File) {
 				fakeFileInfo.On("Size").Return(int64(0)).Times(1)
-				fakeFile.On("Close").Return(nil).Times(1)
 			},
 		},
 		{
@@ -71,7 +70,6 @@ func TestShredder_shred(t *testing.T) {
 				fakeFileInfo.On("Size").Return(int64(64)).Times(4)
 
 				fakeFile.On("Seek", int64(0), 0).Return(int64(0), nil).Times(3)
-				fakeFile.On("Close").Return(nil).Times(1)
 				fakeFile.On("Sync").Return(nil).Times(3)
 				fakeFile.On("Write", mock.MatchedBy(func(b []byte) bool {
 					return len(b) != 0
@@ -89,7 +87,6 @@ func TestShredder_shred(t *testing.T) {
 				fakeFileInfo.On("Size").Return(int64(2000000)).Times(11)
 
 				fakeFile.On("Seek", int64(0), 0).Return(int64(0), nil).Times(10)
-				fakeFile.On("Close").Return(nil).Times(1)
 				fakeFile.On("Sync").Return(nil).Times(10)
 				fakeFile.On("Write", mock.MatchedBy(func(b []byte) bool {
 					return len(b) != 0
@@ -107,34 +104,12 @@ func TestShredder_shred(t *testing.T) {
 				fakeFileInfo.On("Size").Return(int64(2000)).Times(2)
 
 				fakeFile.On("Seek", int64(0), 0).Return(int64(0), nil).Times(1)
-				fakeFile.On("Close").Return(nil).Times(1)
 				fakeFile.On("Write", mock.MatchedBy(func(b []byte) bool {
 					return len(b) != 0
 				})).Return(0, errors.New("dummy error"))
 			},
 			wantError: errors.New("dummy error"),
 		},
-		{
-			name: "test writing a 2Kb file with zero option",
-			options: ShredderOptions{
-				Zero:       true,
-				Iterations: 5,
-				Unlink:     false,
-			},
-			mocks: func(fakeFileInfo *mocks.FileInfo, fakeFile *mocks.File) {
-				fakeFileInfo.On("Size").Return(int64(2000)).Times(6)
-
-				fakeFile.On("Close").Return(nil).Times(1)
-				fakeFile.On("Seek", int64(0), 0).Return(int64(0), nil).Times(5)
-				fakeFile.On("Sync").Return(nil).Times(5)
-				fakeFile.On("Write", mock.MatchedBy(func(b []byte) bool {
-					return len(b) > 0
-				})).Return(0, nil)
-				fakeFile.On("Write", mock.MatchedBy(func(b []byte) bool {
-					return len(b) == 0
-				})).Return(0, nil).Once()
-			},
-		},
 	}
 
 	for _, tt := range cases {