arrow_csv/

writer.rs

// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! CSV Writing: [`Writer`] and [`WriterBuilder`]
//!
//! This CSV writer allows Arrow data (in record batches) to be written as CSV files.
//! The writer does not support writing `ListArray` and `StructArray`.
//!
//! # Example
//! ```
//! # use arrow_array::*;
//! # use arrow_array::types::*;
//! # use arrow_csv::Writer;
//! # use arrow_schema::*;
//! # use std::sync::Arc;
//!
//! let schema = Schema::new(vec![
//!     Field::new("c1", DataType::Utf8, false),
//!     Field::new("c2", DataType::Float64, true),
//!     Field::new("c3", DataType::UInt32, false),
//!     Field::new("c4", DataType::Boolean, true),
//! ]);
//! let c1 = StringArray::from(vec![
//!     "Lorem ipsum dolor sit amet",
//!     "consectetur adipiscing elit",
//!     "sed do eiusmod tempor",
//! ]);
//! let c2 = PrimitiveArray::<Float64Type>::from(vec![
//!     Some(123.564532),
//!     None,
//!     Some(-556132.25),
//! ]);
//! let c3 = PrimitiveArray::<UInt32Type>::from(vec![3, 2, 1]);
//! let c4 = BooleanArray::from(vec![Some(true), Some(false), None]);
//!
//! let batch = RecordBatch::try_new(
//!     Arc::new(schema),
//!     vec![Arc::new(c1), Arc::new(c2), Arc::new(c3), Arc::new(c4)],
//! )
//! .unwrap();
//!
//! let mut output = Vec::with_capacity(1024);
//!
//! let mut writer = Writer::new(&mut output);
//! let batches = vec![&batch, &batch];
//! for batch in batches {
//!     writer.write(batch).unwrap();
//! }
//! ```
//!
//! # Whitespace Handling
//!
//! The writer supports trimming leading and trailing whitespace from string values,
//! compatible with Apache Spark's CSV options `ignoreLeadingWhiteSpace` and
//! `ignoreTrailingWhiteSpace`. This is useful when working with data that may have
//! unwanted padding.
//!
//! Whitespace trimming is applied to all string data types:
//! - `DataType::Utf8`
//! - `DataType::LargeUtf8`
//! - `DataType::Utf8View`
//!
//! ## Example: Use [`WriterBuilder`] to control whitespace handling
//!
//! ```
//! # use arrow_array::*;
//! # use arrow_csv::WriterBuilder;
//! # use arrow_schema::*;
//! # use std::sync::Arc;
//! let schema = Schema::new(vec![
//!     Field::new("name", DataType::Utf8, false),
//!     Field::new("comment", DataType::Utf8, false),
//! ]);
//!
//! let name = StringArray::from(vec![
//!     "  Alice  ",   // Leading and trailing spaces
//!     "Bob",         // No spaces
//!     "  Charlie",   // Leading spaces only
//! ]);
//! let comment = StringArray::from(vec![
//!     "  Great job!  ",
//!     "Well done",
//!     "Excellent  ",
//! ]);
//!
//! let batch = RecordBatch::try_new(
//!     Arc::new(schema),
//!     vec![Arc::new(name), Arc::new(comment)],
//! )
//! .unwrap();
//!
//! // Trim both leading and trailing whitespace
//! let mut output = Vec::new();
//! WriterBuilder::new()
//!     .with_ignore_leading_whitespace(true)
//!     .with_ignore_trailing_whitespace(true)
//!     .build(&mut output)
//!     .write(&batch)
//!     .unwrap();
//! assert_eq!(
//!     String::from_utf8(output).unwrap(),
//!     "\
//! name,comment\n\
//! Alice,Great job!\n\
//! Bob,Well done\n\
//! Charlie,Excellent\n"
//! );
//! ```
//!
//! # Quoting Styles
//!
//! The writer supports different quoting styles for fields, compatible with Apache Spark's
//! CSV options like `quoteAll`. You can control when fields are quoted using the
//! [`QuoteStyle`] enum.
//!
//! ## Example
//!
//! ```
//! # use arrow_array::*;
//! # use arrow_csv::{WriterBuilder, QuoteStyle};
//! # use arrow_schema::*;
//! # use std::sync::Arc;
//!
//! let schema = Schema::new(vec![
//!     Field::new("product", DataType::Utf8, false),
//!     Field::new("price", DataType::Float64, false),
//! ]);
//!
//! let product = StringArray::from(vec!["apple", "banana,organic", "cherry"]);
//! let price = Float64Array::from(vec![1.50, 2.25, 3.00]);
//!
//! let batch = RecordBatch::try_new(
//!     Arc::new(schema),
//!     vec![Arc::new(product), Arc::new(price)],
//! )
//! .unwrap();
//!
//! // Default behavior (QuoteStyle::Necessary)
//! let mut output = Vec::new();
//! WriterBuilder::new()
//!     .build(&mut output)
//!     .write(&batch)
//!     .unwrap();
//! assert_eq!(
//!     String::from_utf8(output).unwrap(),
//!     "product,price\napple,1.5\n\"banana,organic\",2.25\ncherry,3.0\n"
//! );
//!
//! // Quote all fields (Spark's quoteAll=true)
//! let mut output = Vec::new();
//! WriterBuilder::new()
//!     .with_quote_style(QuoteStyle::Always)
//!     .build(&mut output)
//!     .write(&batch)
//!     .unwrap();
//! assert_eq!(
//!     String::from_utf8(output).unwrap(),
//!     "\"product\",\"price\"\n\"apple\",\"1.5\"\n\"banana,organic\",\"2.25\"\n\"cherry\",\"3.0\"\n"
//! );
//! ```

use arrow_array::*;
use arrow_cast::display::*;
use arrow_schema::*;
use csv::ByteRecord;
use std::io::Write;

use crate::map_csv_error;
const DEFAULT_NULL_VALUE: &str = "";

/// The quoting style to use when writing CSV files.
///
/// This type is re-exported from the `csv` crate and supports different
/// strategies for quoting fields. It is compatible with Apache Spark's
/// CSV options like `quoteAll`.
///
/// # Example
///
/// ```
/// use arrow_csv::{WriterBuilder, QuoteStyle};
///
/// let builder = WriterBuilder::new()
///     .with_quote_style(QuoteStyle::Always); // Equivalent to Spark's quoteAll=true
/// ```
pub use csv::QuoteStyle;

/// A CSV writer
///
/// See the [module documentation](crate::writer) for examples.
#[derive(Debug)]
pub struct Writer<W: Write> {
    /// The object to write to
    writer: csv::Writer<W>,
    /// Whether file should be written with headers, defaults to `true`
    has_headers: bool,
    /// The date format for date arrays, defaults to RFC3339
    date_format: Option<String>,
    /// The datetime format for datetime arrays, defaults to RFC3339
    datetime_format: Option<String>,
    /// The timestamp format for timestamp arrays, defaults to RFC3339
    timestamp_format: Option<String>,
    /// The timestamp format for timestamp (with timezone) arrays, defaults to RFC3339
    timestamp_tz_format: Option<String>,
    /// The time format for time arrays, defaults to RFC3339
    time_format: Option<String>,
    /// Is the beginning-of-writer
    beginning: bool,
    /// The value to represent null entries, defaults to [`DEFAULT_NULL_VALUE`]
    null_value: Option<String>,
    /// Whether to ignore leading whitespace in string values
    ignore_leading_whitespace: bool,
    /// Whether to ignore trailing whitespace in string values
    ignore_trailing_whitespace: bool,
}

impl<W: Write> Writer<W> {
    /// Create a new CsvWriter from a writable object, with default options
    ///
    /// See [`WriterBuilder`] for configure options, and the [module
    /// documentation](crate::writer) for examples.
    pub fn new(writer: W) -> Self {
        let delimiter = b',';
        WriterBuilder::new().with_delimiter(delimiter).build(writer)
    }

    /// Write a RecordBatch to the underlying writer
    pub fn write(&mut self, batch: &RecordBatch) -> Result<(), ArrowError> {
        let num_columns = batch.num_columns();
        if self.beginning {
            if self.has_headers {
                let mut headers: Vec<String> = Vec::with_capacity(num_columns);
                batch
                    .schema()
                    .fields()
                    .iter()
                    .for_each(|field| headers.push(field.name().to_string()));
                self.writer
                    .write_record(&headers[..])
                    .map_err(map_csv_error)?;
            }
            self.beginning = false;
        }

        let options = FormatOptions::default()
            .with_null(self.null_value.as_deref().unwrap_or(DEFAULT_NULL_VALUE))
            .with_date_format(self.date_format.as_deref())
            .with_datetime_format(self.datetime_format.as_deref())
            .with_timestamp_format(self.timestamp_format.as_deref())
            .with_timestamp_tz_format(self.timestamp_tz_format.as_deref())
            .with_time_format(self.time_format.as_deref());

        let converters = batch
            .columns()
            .iter()
            .map(|a| {
                if a.data_type().is_nested() {
                    Err(ArrowError::CsvError(format!(
                        "Nested type {} is not supported in CSV",
                        a.data_type()
                    )))
                } else {
                    ArrayFormatter::try_new(a.as_ref(), &options)
                }
            })
            .collect::<Result<Vec<_>, ArrowError>>()?;

        let mut buffer = String::with_capacity(1024);
        let mut byte_record = ByteRecord::with_capacity(1024, converters.len());

        for row_idx in 0..batch.num_rows() {
            byte_record.clear();
            for (col_idx, converter) in converters.iter().enumerate() {
                buffer.clear();
                converter.value(row_idx).write(&mut buffer).map_err(|e| {
                    ArrowError::CsvError(format!(
                        "Error processing row {}, col {}: {e}",
                        row_idx + 1,
                        col_idx + 1
                    ))
                })?;

                let field_bytes =
                    self.get_trimmed_field_bytes(&buffer, batch.column(col_idx).data_type());
                byte_record.push_field(field_bytes);
            }

            self.writer
                .write_byte_record(&byte_record)
                .map_err(map_csv_error)?;
        }
        self.writer.flush()?;

        Ok(())
    }

    /// Returns the bytes for a field, applying whitespace trimming if configured and applicable
    fn get_trimmed_field_bytes<'a>(&self, buffer: &'a str, data_type: &DataType) -> &'a [u8] {
        // Only trim string types when trimming is enabled
        let should_trim = (self.ignore_leading_whitespace || self.ignore_trailing_whitespace)
            && matches!(
                data_type,
                DataType::Utf8 | DataType::LargeUtf8 | DataType::Utf8View
            );

        if !should_trim {
            return buffer.as_bytes();
        }

        let mut trimmed = buffer;
        if self.ignore_leading_whitespace {
            trimmed = trimmed.trim_start();
        }
        if self.ignore_trailing_whitespace {
            trimmed = trimmed.trim_end();
        }
        trimmed.as_bytes()
    }

    /// Unwraps this `Writer<W>`, returning the underlying writer.
    pub fn into_inner(self) -> W {
        // Safe to call `unwrap` since `write` always flushes the writer.
        self.writer.into_inner().unwrap()
    }
}

impl<W: Write> RecordBatchWriter for Writer<W> {
    fn write(&mut self, batch: &RecordBatch) -> Result<(), ArrowError> {
        self.write(batch)
    }

    fn close(self) -> Result<(), ArrowError> {
        Ok(())
    }
}

/// A CSV writer builder
#[derive(Clone, Debug)]
pub struct WriterBuilder {
    /// Optional column delimiter. Defaults to `b','`
    delimiter: u8,
    /// Whether to write column names as file headers. Defaults to `true`
    has_header: bool,
    /// Optional quote character. Defaults to `b'"'`
    quote: u8,
    /// Optional escape character. Defaults to `b'\\'`
    escape: u8,
    /// Optional line terminator. Defaults to `LF` (`\n`)
    terminator: Terminator,
    /// Enable double quote escapes. Defaults to `true`
    double_quote: bool,
    /// Optional date format for date arrays
    date_format: Option<String>,
    /// Optional datetime format for datetime arrays
    datetime_format: Option<String>,
    /// Optional timestamp format for timestamp arrays
    timestamp_format: Option<String>,
    /// Optional timestamp format for timestamp with timezone arrays
    timestamp_tz_format: Option<String>,
    /// Optional time format for time arrays
    time_format: Option<String>,
    /// Optional value to represent null
    null_value: Option<String>,
    /// Whether to ignore leading whitespace in string values. Defaults to `false`
    ignore_leading_whitespace: bool,
    /// Whether to ignore trailing whitespace in string values. Defaults to `false`
    ignore_trailing_whitespace: bool,
    /// The quoting style to use. Defaults to `QuoteStyle::Necessary`
    quote_style: QuoteStyle,
}

/// The line terminator to use when writing CSV files.
#[derive(Clone, Debug)]
pub enum Terminator {
    /// Use CRLF (`\r\n`) as the line terminator
    CRLF,
    /// Use the specified byte character as the line terminator
    Any(u8),
}

impl Default for WriterBuilder {
    fn default() -> Self {
        WriterBuilder {
            delimiter: b',',
            has_header: true,
            quote: b'"',
            escape: b'\\',
            terminator: Terminator::Any(b'\n'),
            double_quote: true,
            date_format: None,
            datetime_format: None,
            timestamp_format: None,
            timestamp_tz_format: None,
            time_format: None,
            null_value: None,
            ignore_leading_whitespace: false,
            ignore_trailing_whitespace: false,
            quote_style: QuoteStyle::default(),
        }
    }
}

impl WriterBuilder {
    /// Create a new builder for configuring CSV [`Writer`] options.
    ///
    /// To convert a builder into a writer, call [`WriterBuilder::build`]. See
    /// the [module documentation](crate::writer) for more examples.
    ///
    /// # Example
    ///
    /// ```
    /// # use arrow_csv::{Writer, WriterBuilder};
    /// # use std::fs::File;
    ///
    /// fn example() -> Writer<File> {
    ///     let file = File::create("target/out.csv").unwrap();
    ///
    ///     // create a builder that doesn't write headers
    ///     let builder = WriterBuilder::new().with_header(false);
    ///     let writer = builder.build(file);
    ///
    ///     writer
    /// }
    /// ```
    pub fn new() -> Self {
        Self::default()
    }

    /// Set whether to write the CSV file with a header
    pub fn with_header(mut self, header: bool) -> Self {
        self.has_header = header;
        self
    }

    /// Returns `true` if this writer is configured to write a header
    pub fn header(&self) -> bool {
        self.has_header
    }

    /// Set the CSV file's column delimiter as a byte character
    pub fn with_delimiter(mut self, delimiter: u8) -> Self {
        self.delimiter = delimiter;
        self
    }

    /// Get the CSV file's column delimiter as a byte character
    pub fn delimiter(&self) -> u8 {
        self.delimiter
    }

    /// Set the CSV file's quote character as a byte character
    pub fn with_quote(mut self, quote: u8) -> Self {
        self.quote = quote;
        self
    }

    /// Get the CSV file's quote character as a byte character
    pub fn quote(&self) -> u8 {
        self.quote
    }

    /// Set the CSV file's escape character as a byte character
    ///
    /// In some variants of CSV, quotes are escaped using a special escape
    /// character like `\` (instead of escaping quotes by doubling them).
    ///
    /// By default, writing these idiosyncratic escapes is disabled, and is
    /// only used when `double_quote` is disabled.
    pub fn with_escape(mut self, escape: u8) -> Self {
        self.escape = escape;
        self
    }

    /// Get the CSV file's escape character as a byte character
    pub fn escape(&self) -> u8 {
        self.escape
    }

    /// Set whether to enable double quote escapes
    ///
    /// When enabled (which is the default), quotes are escaped by doubling
    /// them. e.g., `"` escapes to `""`.
    ///
    /// When disabled, quotes are escaped with the escape character (which
    /// is `\\` by default).
    pub fn with_double_quote(mut self, double_quote: bool) -> Self {
        self.double_quote = double_quote;
        self
    }

    /// Get whether double quote escapes are enabled
    pub fn double_quote(&self) -> bool {
        self.double_quote
    }

    /// Set the CSV file's date format
    pub fn with_date_format(mut self, format: String) -> Self {
        self.date_format = Some(format);
        self
    }

    /// Get the CSV file's date format if set, defaults to RFC3339
    pub fn date_format(&self) -> Option<&str> {
        self.date_format.as_deref()
    }

    /// Set the CSV file's datetime format
    pub fn with_datetime_format(mut self, format: String) -> Self {
        self.datetime_format = Some(format);
        self
    }

    /// Get the CSV file's datetime format if set, defaults to RFC3339
    pub fn datetime_format(&self) -> Option<&str> {
        self.datetime_format.as_deref()
    }

    /// Set the CSV file's time format
    pub fn with_time_format(mut self, format: String) -> Self {
        self.time_format = Some(format);
        self
    }

    /// Get the CSV file's datetime time if set, defaults to RFC3339
    pub fn time_format(&self) -> Option<&str> {
        self.time_format.as_deref()
    }

    /// Set the CSV file's timestamp format
    pub fn with_timestamp_format(mut self, format: String) -> Self {
        self.timestamp_format = Some(format);
        self
    }

    /// Get the CSV file's timestamp format if set, defaults to RFC3339
    pub fn timestamp_format(&self) -> Option<&str> {
        self.timestamp_format.as_deref()
    }

    /// Set the CSV file's timestamp tz format
    pub fn with_timestamp_tz_format(mut self, tz_format: String) -> Self {
        self.timestamp_tz_format = Some(tz_format);
        self
    }

    /// Get the CSV file's timestamp tz format if set, defaults to RFC3339
    pub fn timestamp_tz_format(&self) -> Option<&str> {
        self.timestamp_tz_format.as_deref()
    }

    /// Set the value to represent null in output
    pub fn with_null(mut self, null_value: String) -> Self {
        self.null_value = Some(null_value);
        self
    }

    /// Get the value to represent null in output
    pub fn null(&self) -> &str {
        self.null_value.as_deref().unwrap_or(DEFAULT_NULL_VALUE)
    }

    /// Set whether to ignore leading whitespace in string values
    /// For example, a string value such as "   foo" will be written as "foo"
    pub fn with_ignore_leading_whitespace(mut self, ignore: bool) -> Self {
        self.ignore_leading_whitespace = ignore;
        self
    }

    /// Get whether to ignore leading whitespace in string values
    pub fn ignore_leading_whitespace(&self) -> bool {
        self.ignore_leading_whitespace
    }

    /// Set whether to ignore trailing whitespace in string values
    /// For example, a string value such as "foo    " will be written as "foo"
    pub fn with_ignore_trailing_whitespace(mut self, ignore: bool) -> Self {
        self.ignore_trailing_whitespace = ignore;
        self
    }

    /// Get whether to ignore trailing whitespace in string values
    pub fn ignore_trailing_whitespace(&self) -> bool {
        self.ignore_trailing_whitespace
    }

    /// Set the quoting style for writing CSV files
    ///
    /// # Example
    ///
    /// ```
    /// use arrow_csv::{WriterBuilder, QuoteStyle};
    ///
    /// // Quote all fields (equivalent to Spark's quoteAll=true)
    /// let builder = WriterBuilder::new()
    ///     .with_quote_style(QuoteStyle::Always);
    ///
    /// // Only quote when necessary (default)
    /// let builder = WriterBuilder::new()
    ///     .with_quote_style(QuoteStyle::Necessary);
    /// ```
    pub fn with_quote_style(mut self, quote_style: QuoteStyle) -> Self {
        self.quote_style = quote_style;
        self
    }

    /// Get the configured quoting style
    pub fn quote_style(&self) -> QuoteStyle {
        self.quote_style
    }

    /// Set the CSV file's line terminator
    pub fn with_line_terminator(mut self, terminator: Terminator) -> Self {
        self.terminator = terminator;
        self
    }

    /// Get the CSV file's line terminator, defaults to `LF` (`\n`)
    pub fn line_terminator(&self) -> &Terminator {
        &self.terminator
    }

    /// Create a new `Writer`
    pub fn build<W: Write>(self, writer: W) -> Writer<W> {
        let mut builder = csv::WriterBuilder::new();

        let terminator = match self.terminator {
            Terminator::CRLF => csv::Terminator::CRLF,
            Terminator::Any(byte) => csv::Terminator::Any(byte),
        };

        let writer = builder
            .delimiter(self.delimiter)
            .quote(self.quote)
            .quote_style(self.quote_style)
            .double_quote(self.double_quote)
            .escape(self.escape)
            .terminator(terminator)
            .from_writer(writer);
        Writer {
            writer,
            beginning: true,
            has_headers: self.has_header,
            date_format: self.date_format,
            datetime_format: self.datetime_format,
            time_format: self.time_format,
            timestamp_format: self.timestamp_format,
            timestamp_tz_format: self.timestamp_tz_format,
            null_value: self.null_value,
            ignore_leading_whitespace: self.ignore_leading_whitespace,
            ignore_trailing_whitespace: self.ignore_trailing_whitespace,
        }
    }
}

#[cfg(test)]
#[expect(
    clippy::verbose_file_reads,
    reason = "`tempfile::tempfile()` has no path, so the contents can only be read back through the handle"
)]
mod tests {
    use super::*;

    use crate::ReaderBuilder;
    use arrow_array::builder::{
        BinaryBuilder, Decimal32Builder, Decimal64Builder, Decimal128Builder, Decimal256Builder,
        FixedSizeBinaryBuilder, LargeBinaryBuilder,
    };
    use arrow_array::types::*;
    use arrow_buffer::i256;
    use core::str;
    use std::io::{Cursor, Read, Seek};
    use std::sync::Arc;

    #[test]
    fn test_write_csv() {
        let schema = Schema::new(vec![
            Field::new("c1", DataType::Utf8, false),
            Field::new("c2", DataType::Float64, true),
            Field::new("c3", DataType::UInt32, false),
            Field::new("c4", DataType::Boolean, true),
            Field::new("c5", DataType::Timestamp(TimeUnit::Millisecond, None), true),
            Field::new("c6", DataType::Time32(TimeUnit::Second), false),
            Field::new_dictionary("c7", DataType::Int32, DataType::Utf8, false),
        ]);

        let c1 = StringArray::from(vec![
            "Lorem ipsum dolor sit amet",
            "consectetur adipiscing elit",
            "sed do eiusmod tempor",
        ]);
        let c2 =
            PrimitiveArray::<Float64Type>::from(vec![Some(123.564532), None, Some(-556132.25)]);
        let c3 = PrimitiveArray::<UInt32Type>::from(vec![3, 2, 1]);
        let c4 = BooleanArray::from(vec![Some(true), Some(false), None]);
        let c5 =
            TimestampMillisecondArray::from(vec![None, Some(1555584887378), Some(1555555555555)]);
        let c6 = Time32SecondArray::from(vec![1234, 24680, 85563]);
        let c7: DictionaryArray<Int32Type> =
            vec!["cupcakes", "cupcakes", "foo"].into_iter().collect();

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![
                Arc::new(c1),
                Arc::new(c2),
                Arc::new(c3),
                Arc::new(c4),
                Arc::new(c5),
                Arc::new(c6),
                Arc::new(c7),
            ],
        )
        .unwrap();

        let mut file = tempfile::tempfile().unwrap();

        let mut writer = Writer::new(&mut file);
        let batches = vec![&batch, &batch];
        for batch in batches {
            writer.write(batch).unwrap();
        }
        drop(writer);

        // check that file was written successfully
        file.rewind().unwrap();
        let mut buffer: Vec<u8> = vec![];
        file.read_to_end(&mut buffer).unwrap();

        let expected = r"c1,c2,c3,c4,c5,c6,c7
Lorem ipsum dolor sit amet,123.564532,3,true,,00:20:34,cupcakes
consectetur adipiscing elit,,2,false,2019-04-18T10:54:47.378,06:51:20,cupcakes
sed do eiusmod tempor,-556132.25,1,,2019-04-18T02:45:55.555,23:46:03,foo
Lorem ipsum dolor sit amet,123.564532,3,true,,00:20:34,cupcakes
consectetur adipiscing elit,,2,false,2019-04-18T10:54:47.378,06:51:20,cupcakes
sed do eiusmod tempor,-556132.25,1,,2019-04-18T02:45:55.555,23:46:03,foo
";
        assert_eq!(expected, str::from_utf8(&buffer).unwrap());
    }

    #[test]
    fn test_write_csv_decimal() {
        let schema = Schema::new(vec![
            Field::new("c1", DataType::Decimal32(9, 6), true),
            Field::new("c2", DataType::Decimal64(17, 6), true),
            Field::new("c3", DataType::Decimal128(38, 6), true),
            Field::new("c4", DataType::Decimal256(76, 6), true),
        ]);

        let mut c1_builder = Decimal32Builder::new().with_data_type(DataType::Decimal32(9, 6));
        c1_builder.extend(vec![Some(-3335724), Some(2179404), None, Some(290472)]);
        let c1 = c1_builder.finish();

        let mut c2_builder = Decimal64Builder::new().with_data_type(DataType::Decimal64(17, 6));
        c2_builder.extend(vec![Some(-3335724), Some(2179404), None, Some(290472)]);
        let c2 = c2_builder.finish();

        let mut c3_builder = Decimal128Builder::new().with_data_type(DataType::Decimal128(38, 6));
        c3_builder.extend(vec![Some(-3335724), Some(2179404), None, Some(290472)]);
        let c3 = c3_builder.finish();

        let mut c4_builder = Decimal256Builder::new().with_data_type(DataType::Decimal256(76, 6));
        c4_builder.extend(vec![
            Some(i256::from_i128(-3335724)),
            Some(i256::from_i128(2179404)),
            None,
            Some(i256::from_i128(290472)),
        ]);
        let c4 = c4_builder.finish();

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![Arc::new(c1), Arc::new(c2), Arc::new(c3), Arc::new(c4)],
        )
        .unwrap();

        let mut file = tempfile::tempfile().unwrap();

        let mut writer = Writer::new(&mut file);
        let batches = vec![&batch, &batch];
        for batch in batches {
            writer.write(batch).unwrap();
        }
        drop(writer);

        // check that file was written successfully
        file.rewind().unwrap();
        let mut buffer: Vec<u8> = vec![];
        file.read_to_end(&mut buffer).unwrap();

        let expected = r"c1,c2,c3,c4
-3.335724,-3.335724,-3.335724,-3.335724
2.179404,2.179404,2.179404,2.179404
,,,
0.290472,0.290472,0.290472,0.290472
-3.335724,-3.335724,-3.335724,-3.335724
2.179404,2.179404,2.179404,2.179404
,,,
0.290472,0.290472,0.290472,0.290472
";
        assert_eq!(expected, str::from_utf8(&buffer).unwrap());
    }

    #[test]
    fn test_write_csv_custom_options() {
        let schema = Schema::new(vec![
            Field::new("c1", DataType::Utf8, false),
            Field::new("c2", DataType::Float64, true),
            Field::new("c3", DataType::UInt32, false),
            Field::new("c4", DataType::Boolean, true),
            Field::new("c6", DataType::Time32(TimeUnit::Second), false),
        ]);

        let c1 = StringArray::from(vec![
            "Lorem ipsum \ndolor sit amet",
            "consectetur \"adipiscing\" elit",
            "sed do eiusmod tempor",
        ]);
        let c2 =
            PrimitiveArray::<Float64Type>::from(vec![Some(123.564532), None, Some(-556132.25)]);
        let c3 = PrimitiveArray::<UInt32Type>::from(vec![3, 2, 1]);
        let c4 = BooleanArray::from(vec![Some(true), Some(false), None]);
        let c6 = Time32SecondArray::from(vec![1234, 24680, 85563]);

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![
                Arc::new(c1),
                Arc::new(c2),
                Arc::new(c3),
                Arc::new(c4),
                Arc::new(c6),
            ],
        )
        .unwrap();

        let mut file = tempfile::tempfile().unwrap();

        let builder = WriterBuilder::new()
            .with_header(false)
            .with_delimiter(b'|')
            .with_quote(b'\'')
            .with_null("NULL".to_string())
            .with_time_format("%r".to_string());
        let mut writer = builder.build(&mut file);
        let batches = vec![&batch];
        for batch in batches {
            writer.write(batch).unwrap();
        }
        drop(writer);

        // check that file was written successfully
        file.rewind().unwrap();
        let mut buffer: Vec<u8> = vec![];
        file.read_to_end(&mut buffer).unwrap();

        assert_eq!(
            "'Lorem ipsum \ndolor sit amet'|123.564532|3|true|12:20:34 AM\nconsectetur \"adipiscing\" elit|NULL|2|false|06:51:20 AM\nsed do eiusmod tempor|-556132.25|1|NULL|11:46:03 PM\n"
            .to_string(),
            String::from_utf8(buffer).unwrap()
        );

        let mut file = tempfile::tempfile().unwrap();

        let builder = WriterBuilder::new()
            .with_header(true)
            .with_double_quote(false)
            .with_escape(b'$');
        let mut writer = builder.build(&mut file);
        let batches = vec![&batch];
        for batch in batches {
            writer.write(batch).unwrap();
        }
        drop(writer);

        file.rewind().unwrap();
        let mut buffer: Vec<u8> = vec![];
        file.read_to_end(&mut buffer).unwrap();

        assert_eq!(
            "c1,c2,c3,c4,c6\n\"Lorem ipsum \ndolor sit amet\",123.564532,3,true,00:20:34\n\"consectetur $\"adipiscing$\" elit\",,2,false,06:51:20\nsed do eiusmod tempor,-556132.25,1,,23:46:03\n"
            .to_string(),
            String::from_utf8(buffer).unwrap()
        );
    }

    #[test]
    fn test_conversion_consistency() {
        // test if we can serialize and deserialize whilst retaining the same type information/ precision

        let schema = Schema::new(vec![
            Field::new("c1", DataType::Date32, false),
            Field::new("c2", DataType::Date64, false),
            Field::new("c3", DataType::Timestamp(TimeUnit::Nanosecond, None), false),
        ]);

        let nanoseconds = vec![
            1599566300000000000,
            1599566200000000000,
            1599566100000000000,
        ];
        let c1 = Date32Array::from(vec![3, 2, 1]);
        let c2 = Date64Array::from(vec![3, 2, 1]);
        let c3 = TimestampNanosecondArray::from(nanoseconds.clone());

        let batch = RecordBatch::try_new(
            Arc::new(schema.clone()),
            vec![Arc::new(c1), Arc::new(c2), Arc::new(c3)],
        )
        .unwrap();

        let builder = WriterBuilder::new().with_header(false);

        let mut buf: Cursor<Vec<u8>> = Default::default();
        // drop the writer early to release the borrow.
        {
            let mut writer = builder.build(&mut buf);
            writer.write(&batch).unwrap();
        }
        buf.set_position(0);

        let mut reader = ReaderBuilder::new(Arc::new(schema))
            .with_batch_size(3)
            .build_buffered(buf)
            .unwrap();

        let rb = reader.next().unwrap().unwrap();
        let c1 = rb.column(0).as_any().downcast_ref::<Date32Array>().unwrap();
        let c2 = rb.column(1).as_any().downcast_ref::<Date64Array>().unwrap();
        let c3 = rb
            .column(2)
            .as_any()
            .downcast_ref::<TimestampNanosecondArray>()
            .unwrap();

        let actual = c1.into_iter().collect::<Vec<_>>();
        let expected = vec![Some(3), Some(2), Some(1)];
        assert_eq!(actual, expected);
        let actual = c2.into_iter().collect::<Vec<_>>();
        let expected = vec![Some(3), Some(2), Some(1)];
        assert_eq!(actual, expected);
        let actual = c3.into_iter().collect::<Vec<_>>();
        let expected = nanoseconds.into_iter().map(Some).collect::<Vec<_>>();
        assert_eq!(actual, expected);
    }

    #[test]
    fn test_write_csv_invalid_cast() {
        let schema = Schema::new(vec![
            Field::new("c0", DataType::UInt32, false),
            Field::new("c1", DataType::Date64, false),
        ]);

        let c0 = UInt32Array::from(vec![Some(123), Some(234)]);
        let c1 = Date64Array::from(vec![Some(1926632005177), Some(1926632005177685347)]);
        let batch =
            RecordBatch::try_new(Arc::new(schema), vec![Arc::new(c0), Arc::new(c1)]).unwrap();

        let mut file = tempfile::tempfile().unwrap();
        let mut writer = Writer::new(&mut file);
        let batches = vec![&batch, &batch];

        for batch in batches {
            let err = writer.write(batch).unwrap_err().to_string();
            assert_eq!(
                err,
                "Csv error: Error processing row 2, col 2: Cast error: Failed to convert 1926632005177685347 to temporal for Date64"
            )
        }
        drop(writer);
    }

    #[test]
    fn test_write_csv_using_rfc3339() {
        let schema = Schema::new(vec![
            Field::new(
                "c1",
                DataType::Timestamp(TimeUnit::Millisecond, Some("+00:00".into())),
                true,
            ),
            Field::new("c2", DataType::Timestamp(TimeUnit::Millisecond, None), true),
            Field::new("c3", DataType::Date32, false),
            Field::new("c4", DataType::Time32(TimeUnit::Second), false),
        ]);

        let c1 = TimestampMillisecondArray::from(vec![Some(1555584887378), Some(1635577147000)])
            .with_timezone("+00:00".to_string());
        let c2 = TimestampMillisecondArray::from(vec![Some(1555584887378), Some(1635577147000)]);
        let c3 = Date32Array::from(vec![3, 2]);
        let c4 = Time32SecondArray::from(vec![1234, 24680]);

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![Arc::new(c1), Arc::new(c2), Arc::new(c3), Arc::new(c4)],
        )
        .unwrap();

        let mut file = tempfile::tempfile().unwrap();

        let builder = WriterBuilder::new();
        let mut writer = builder.build(&mut file);
        let batches = vec![&batch];
        for batch in batches {
            writer.write(batch).unwrap();
        }
        drop(writer);

        file.rewind().unwrap();
        let mut buffer: Vec<u8> = vec![];
        file.read_to_end(&mut buffer).unwrap();

        assert_eq!(
            "c1,c2,c3,c4
2019-04-18T10:54:47.378Z,2019-04-18T10:54:47.378,1970-01-04,00:20:34
2021-10-30T06:59:07Z,2021-10-30T06:59:07,1970-01-03,06:51:20\n",
            String::from_utf8(buffer).unwrap()
        );
    }

    #[test]
    fn test_write_csv_tz_format() {
        let schema = Schema::new(vec![
            Field::new(
                "c1",
                DataType::Timestamp(TimeUnit::Millisecond, Some("+02:00".into())),
                true,
            ),
            Field::new(
                "c2",
                DataType::Timestamp(TimeUnit::Second, Some("+04:00".into())),
                true,
            ),
        ]);
        let c1 = TimestampMillisecondArray::from(vec![Some(1_000), Some(2_000)])
            .with_timezone("+02:00".to_string());
        let c2 = TimestampSecondArray::from(vec![Some(1_000_000), None])
            .with_timezone("+04:00".to_string());
        let batch =
            RecordBatch::try_new(Arc::new(schema), vec![Arc::new(c1), Arc::new(c2)]).unwrap();

        let mut file = tempfile::tempfile().unwrap();
        let mut writer = WriterBuilder::new()
            .with_timestamp_tz_format("%M:%H".to_string())
            .build(&mut file);
        writer.write(&batch).unwrap();

        drop(writer);
        file.rewind().unwrap();
        let mut buffer: Vec<u8> = vec![];
        file.read_to_end(&mut buffer).unwrap();

        let output = String::from_utf8(buffer).unwrap();
        assert_eq!(output, "c1,c2\n00:02,46:17\n00:02,\n");
    }

    #[test]
    fn test_write_csv_with_lf_terminator() {
        let output = write_batch_with_terminator(Terminator::Any(b'\n'));
        assert_eq!(output, "c1,c2\nhello,1\nworld,2\n");
    }

    #[test]
    fn test_write_csv_with_crlf_terminator() {
        let output = write_batch_with_terminator(Terminator::CRLF);
        assert_eq!(output, "c1,c2\r\nhello,1\r\nworld,2\r\n");
    }

    #[test]
    fn test_write_csv_with_any_terminator() {
        let output = write_batch_with_terminator(Terminator::Any(b'|'));
        assert_eq!(output, "c1,c2|hello,1|world,2|");
    }

    fn write_batch_with_terminator(terminator: Terminator) -> String {
        let schema = Schema::new(vec![
            Field::new("c1", DataType::Utf8, false),
            Field::new("c2", DataType::UInt32, false),
        ]);

        let c1 = StringArray::from(vec!["hello", "world"]);
        let c2 = PrimitiveArray::<UInt32Type>::from(vec![1, 2]);

        let batch =
            RecordBatch::try_new(Arc::new(schema), vec![Arc::new(c1), Arc::new(c2)]).unwrap();

        let mut buf = Vec::new();
        let mut writer = WriterBuilder::new()
            .with_line_terminator(terminator)
            .build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);

        String::from_utf8(buf).unwrap()
    }

    #[test]
    fn test_write_csv_binary() {
        let fixed_size = 8;
        let schema = SchemaRef::new(Schema::new(vec![
            Field::new("c1", DataType::Binary, true),
            Field::new("c2", DataType::FixedSizeBinary(fixed_size), true),
            Field::new("c3", DataType::LargeBinary, true),
        ]));
        let mut c1_builder = BinaryBuilder::new();
        c1_builder.append_value(b"Homer");
        c1_builder.append_value(b"Bart");
        c1_builder.append_null();
        c1_builder.append_value(b"Ned");
        let mut c2_builder = FixedSizeBinaryBuilder::new(fixed_size);
        c2_builder.append_value(b"Simpson ").unwrap();
        c2_builder.append_value(b"Simpson ").unwrap();
        c2_builder.append_null();
        c2_builder.append_value(b"Flanders").unwrap();
        let mut c3_builder = LargeBinaryBuilder::new();
        c3_builder.append_null();
        c3_builder.append_null();
        c3_builder.append_value(b"Comic Book Guy");
        c3_builder.append_null();

        let batch = RecordBatch::try_new(
            schema,
            vec![
                Arc::new(c1_builder.finish()) as ArrayRef,
                Arc::new(c2_builder.finish()) as ArrayRef,
                Arc::new(c3_builder.finish()) as ArrayRef,
            ],
        )
        .unwrap();

        let mut buf = Vec::new();
        let builder = WriterBuilder::new();
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "\
            c1,c2,c3\n\
            486f6d6572,53696d70736f6e20,\n\
            42617274,53696d70736f6e20,\n\
            ,,436f6d696320426f6f6b20477579\n\
            4e6564,466c616e64657273,\n\
            ",
            String::from_utf8(buf).unwrap()
        );
    }

    #[test]
    fn test_write_csv_whitespace_handling() {
        let schema = Schema::new(vec![
            Field::new("c1", DataType::Utf8, false),
            Field::new("c2", DataType::Float64, true),
            Field::new("c3", DataType::Utf8, true),
        ]);

        let c1 = StringArray::from(vec![
            "  leading space",
            "trailing space  ",
            "  both spaces  ",
            "no spaces",
        ]);
        let c2 = PrimitiveArray::<Float64Type>::from(vec![
            Some(123.45),
            Some(678.90),
            None,
            Some(111.22),
        ]);
        let c3 = StringArray::from(vec![
            Some("  test  "),
            Some("value  "),
            None,
            Some("  another"),
        ]);

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![Arc::new(c1), Arc::new(c2), Arc::new(c3)],
        )
        .unwrap();

        // Test with no whitespace handling (default)
        let mut buf = Vec::new();
        let builder = WriterBuilder::new();
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "c1,c2,c3\n  leading space,123.45,  test  \ntrailing space  ,678.9,value  \n  both spaces  ,,\nno spaces,111.22,  another\n",
            String::from_utf8(buf).unwrap()
        );

        // Test with ignore leading whitespace only
        let mut buf = Vec::new();
        let builder = WriterBuilder::new().with_ignore_leading_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "c1,c2,c3\nleading space,123.45,test  \ntrailing space  ,678.9,value  \nboth spaces  ,,\nno spaces,111.22,another\n",
            String::from_utf8(buf).unwrap()
        );

        // Test with ignore trailing whitespace only
        let mut buf = Vec::new();
        let builder = WriterBuilder::new().with_ignore_trailing_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "c1,c2,c3\n  leading space,123.45,  test\ntrailing space,678.9,value\n  both spaces,,\nno spaces,111.22,  another\n",
            String::from_utf8(buf).unwrap()
        );

        // Test with both ignore leading and trailing whitespace
        let mut buf = Vec::new();
        let builder = WriterBuilder::new()
            .with_ignore_leading_whitespace(true)
            .with_ignore_trailing_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "c1,c2,c3\nleading space,123.45,test\ntrailing space,678.9,value\nboth spaces,,\nno spaces,111.22,another\n",
            String::from_utf8(buf).unwrap()
        );
    }

    #[test]
    fn test_write_csv_whitespace_with_special_chars() {
        let schema = Schema::new(vec![Field::new("c1", DataType::Utf8, false)]);

        let c1 = StringArray::from(vec![
            "  quoted \"value\"  ",
            "  new\nline  ",
            "  comma,value  ",
            "\ttab\tvalue\t",
        ]);

        let batch = RecordBatch::try_new(Arc::new(schema), vec![Arc::new(c1)]).unwrap();

        // Test with both ignore leading and trailing whitespace
        let mut buf = Vec::new();
        let builder = WriterBuilder::new()
            .with_ignore_leading_whitespace(true)
            .with_ignore_trailing_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);

        // Note: tabs are trimmed as they are whitespace characters
        assert_eq!(
            "c1\n\"quoted \"\"value\"\"\"\n\"new\nline\"\n\"comma,value\"\ntab\tvalue\n",
            String::from_utf8(buf).unwrap()
        );
    }

    #[test]
    fn test_write_csv_whitespace_all_string_types() {
        use arrow_array::{LargeStringArray, StringViewArray};

        let schema = Schema::new(vec![
            Field::new("utf8", DataType::Utf8, false),
            Field::new("large_utf8", DataType::LargeUtf8, false),
            Field::new("utf8_view", DataType::Utf8View, false),
        ]);

        let utf8 = StringArray::from(vec!["  leading", "trailing  ", "  both  ", "no_spaces"]);

        let large_utf8 =
            LargeStringArray::from(vec!["  leading", "trailing  ", "  both  ", "no_spaces"]);

        let utf8_view =
            StringViewArray::from(vec!["  leading", "trailing  ", "  both  ", "no_spaces"]);

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![Arc::new(utf8), Arc::new(large_utf8), Arc::new(utf8_view)],
        )
        .unwrap();

        // Test with no whitespace handling (default)
        let mut buf = Vec::new();
        let builder = WriterBuilder::new();
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "utf8,large_utf8,utf8_view\n  leading,  leading,  leading\ntrailing  ,trailing  ,trailing  \n  both  ,  both  ,  both  \nno_spaces,no_spaces,no_spaces\n",
            String::from_utf8(buf).unwrap()
        );

        // Test with both ignore leading and trailing whitespace
        let mut buf = Vec::new();
        let builder = WriterBuilder::new()
            .with_ignore_leading_whitespace(true)
            .with_ignore_trailing_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "utf8,large_utf8,utf8_view\nleading,leading,leading\ntrailing,trailing,trailing\nboth,both,both\nno_spaces,no_spaces,no_spaces\n",
            String::from_utf8(buf).unwrap()
        );

        // Test with only leading whitespace trimming
        let mut buf = Vec::new();
        let builder = WriterBuilder::new().with_ignore_leading_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "utf8,large_utf8,utf8_view\nleading,leading,leading\ntrailing  ,trailing  ,trailing  \nboth  ,both  ,both  \nno_spaces,no_spaces,no_spaces\n",
            String::from_utf8(buf).unwrap()
        );

        // Test with only trailing whitespace trimming
        let mut buf = Vec::new();
        let builder = WriterBuilder::new().with_ignore_trailing_whitespace(true);
        let mut writer = builder.build(&mut buf);
        writer.write(&batch).unwrap();
        drop(writer);
        assert_eq!(
            "utf8,large_utf8,utf8_view\n  leading,  leading,  leading\ntrailing,trailing,trailing\n  both,  both,  both\nno_spaces,no_spaces,no_spaces\n",
            String::from_utf8(buf).unwrap()
        );
    }

    fn write_quote_style(batch: &RecordBatch, quote_style: QuoteStyle) -> String {
        let mut buf = Vec::new();
        let mut writer = WriterBuilder::new()
            .with_quote_style(quote_style)
            .build(&mut buf);
        writer.write(batch).unwrap();
        drop(writer);
        String::from_utf8(buf).unwrap()
    }

    fn write_quote_style_with_null(
        batch: &RecordBatch,
        quote_style: QuoteStyle,
        null_value: &str,
    ) -> String {
        let mut buf = Vec::new();
        let mut writer = WriterBuilder::new()
            .with_quote_style(quote_style)
            .with_null(null_value.to_string())
            .build(&mut buf);
        writer.write(batch).unwrap();
        drop(writer);
        String::from_utf8(buf).unwrap()
    }

    #[test]
    fn test_write_csv_quote_style() {
        let schema = Schema::new(vec![
            Field::new("text", DataType::Utf8, false),
            Field::new("number", DataType::Int32, false),
            Field::new("float", DataType::Float64, false),
        ]);

        let text = StringArray::from(vec!["hello", "world", "comma,value", "quote\"test"]);
        let number = Int32Array::from(vec![1, 2, 3, 4]);
        let float = Float64Array::from(vec![1.1, 2.2, 3.3, 4.4]);

        let batch = RecordBatch::try_new(
            Arc::new(schema),
            vec![Arc::new(text), Arc::new(number), Arc::new(float)],
        )
        .unwrap();

        // Test with QuoteStyle::Necessary (default)
        assert_eq!(
            "text,number,float\nhello,1,1.1\nworld,2,2.2\n\"comma,value\",3,3.3\n\"quote\"\"test\",4,4.4\n",
            write_quote_style(&batch, QuoteStyle::Necessary)
        );

        // Test with QuoteStyle::Always (equivalent to Spark's quoteAll=true)
        assert_eq!(
            "\"text\",\"number\",\"float\"\n\"hello\",\"1\",\"1.1\"\n\"world\",\"2\",\"2.2\"\n\"comma,value\",\"3\",\"3.3\"\n\"quote\"\"test\",\"4\",\"4.4\"\n",
            write_quote_style(&batch, QuoteStyle::Always)
        );

        // Test with QuoteStyle::NonNumeric
        assert_eq!(
            "\"text\",\"number\",\"float\"\n\"hello\",1,1.1\n\"world\",2,2.2\n\"comma,value\",3,3.3\n\"quote\"\"test\",4,4.4\n",
            write_quote_style(&batch, QuoteStyle::NonNumeric)
        );

        // Test with QuoteStyle::Never (warning: can produce invalid CSV)
        // Note: This produces invalid CSV for fields with commas or quotes
        assert_eq!(
            "text,number,float\nhello,1,1.1\nworld,2,2.2\ncomma,value,3,3.3\nquote\"test,4,4.4\n",
            write_quote_style(&batch, QuoteStyle::Never)
        );
    }

    #[test]
    fn test_write_csv_quote_style_with_nulls() {
        let schema = Schema::new(vec![
            Field::new("text", DataType::Utf8, true),
            Field::new("number", DataType::Int32, true),
        ]);

        let text = StringArray::from(vec![Some("hello"), None, Some("world")]);
        let number = Int32Array::from(vec![Some(1), Some(2), None]);

        let batch =
            RecordBatch::try_new(Arc::new(schema), vec![Arc::new(text), Arc::new(number)]).unwrap();

        // Test with QuoteStyle::Always
        assert_eq!(
            "\"text\",\"number\"\n\"hello\",\"1\"\n\"\",\"2\"\n\"world\",\"\"\n",
            write_quote_style(&batch, QuoteStyle::Always)
        );

        // Test with QuoteStyle::Always and custom null value
        assert_eq!(
            "\"text\",\"number\"\n\"hello\",\"1\"\n\"NULL\",\"2\"\n\"world\",\"NULL\"\n",
            write_quote_style_with_null(&batch, QuoteStyle::Always, "NULL")
        );
    }
}