nautilus_serialization/arrow/
depth.rs

1// -------------------------------------------------------------------------------------------------
2//  Copyright (C) 2015-2025 Nautech Systems Pty Ltd. All rights reserved.
3//  https://nautechsystems.io
4//
5//  Licensed under the GNU Lesser General Public License Version 3.0 (the "License");
6//  You may not use this file except in compliance with the License.
7//  You may obtain a copy of the License at https://www.gnu.org/licenses/lgpl-3.0.en.html
8//
9//  Unless required by applicable law or agreed to in writing, software
10//  distributed under the License is distributed on an "AS IS" BASIS,
11//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12//  See the License for the specific language governing permissions and
13//  limitations under the License.
14// -------------------------------------------------------------------------------------------------
15
16use std::{collections::HashMap, str::FromStr, sync::Arc};
17
18use arrow::{
19    array::{
20        Array, FixedSizeBinaryArray, FixedSizeBinaryBuilder, UInt8Array, UInt32Array, UInt64Array,
21    },
22    datatypes::{DataType, Field, Schema},
23    error::ArrowError,
24    record_batch::RecordBatch,
25};
26use nautilus_model::{
27    data::{
28        depth::{DEPTH10_LEN, OrderBookDepth10},
29        order::BookOrder,
30    },
31    enums::OrderSide,
32    identifiers::InstrumentId,
33    types::{Price, Quantity, fixed::PRECISION_BYTES},
34};
35
36use super::{
37    DecodeDataFromRecordBatch, EncodingError, KEY_INSTRUMENT_ID, KEY_PRICE_PRECISION,
38    KEY_SIZE_PRECISION, extract_column,
39};
40use crate::arrow::{
41    ArrowSchemaProvider, Data, DecodeFromRecordBatch, EncodeToRecordBatch, get_raw_price,
42    get_raw_quantity,
43};
44
45fn get_field_data() -> Vec<(&'static str, DataType)> {
46    vec![
47        ("bid_price", DataType::FixedSizeBinary(PRECISION_BYTES)),
48        ("ask_price", DataType::FixedSizeBinary(PRECISION_BYTES)),
49        ("bid_size", DataType::FixedSizeBinary(PRECISION_BYTES)),
50        ("ask_size", DataType::FixedSizeBinary(PRECISION_BYTES)),
51        ("bid_count", DataType::UInt32),
52        ("ask_count", DataType::UInt32),
53    ]
54}
55
56impl ArrowSchemaProvider for OrderBookDepth10 {
57    fn get_schema(metadata: Option<HashMap<String, String>>) -> Schema {
58        let mut fields = Vec::new();
59        let field_data = get_field_data();
60
61        // Schema is of the form:
62        // bid_price_0, bid_price_1, ..., bid_price_9, ask_price_0, ask_price_1
63        for (name, data_type) in field_data {
64            for i in 0..DEPTH10_LEN {
65                fields.push(Field::new(format!("{name}_{i}"), data_type.clone(), false));
66            }
67        }
68
69        fields.push(Field::new("flags", DataType::UInt8, false));
70        fields.push(Field::new("sequence", DataType::UInt64, false));
71        fields.push(Field::new("ts_event", DataType::UInt64, false));
72        fields.push(Field::new("ts_init", DataType::UInt64, false));
73
74        match metadata {
75            Some(metadata) => Schema::new_with_metadata(fields, metadata),
76            None => Schema::new(fields),
77        }
78    }
79}
80
81fn parse_metadata(
82    metadata: &HashMap<String, String>,
83) -> Result<(InstrumentId, u8, u8), EncodingError> {
84    let instrument_id_str = metadata
85        .get(KEY_INSTRUMENT_ID)
86        .ok_or_else(|| EncodingError::MissingMetadata(KEY_INSTRUMENT_ID))?;
87    let instrument_id = InstrumentId::from_str(instrument_id_str)
88        .map_err(|e| EncodingError::ParseError(KEY_INSTRUMENT_ID, e.to_string()))?;
89
90    let price_precision = metadata
91        .get(KEY_PRICE_PRECISION)
92        .ok_or_else(|| EncodingError::MissingMetadata(KEY_PRICE_PRECISION))?
93        .parse::<u8>()
94        .map_err(|e| EncodingError::ParseError(KEY_PRICE_PRECISION, e.to_string()))?;
95
96    let size_precision = metadata
97        .get(KEY_SIZE_PRECISION)
98        .ok_or_else(|| EncodingError::MissingMetadata(KEY_SIZE_PRECISION))?
99        .parse::<u8>()
100        .map_err(|e| EncodingError::ParseError(KEY_SIZE_PRECISION, e.to_string()))?;
101
102    Ok((instrument_id, price_precision, size_precision))
103}
104
105impl EncodeToRecordBatch for OrderBookDepth10 {
106    fn encode_batch(
107        metadata: &HashMap<String, String>,
108        data: &[Self],
109    ) -> Result<RecordBatch, ArrowError> {
110        let mut bid_price_builders = Vec::with_capacity(DEPTH10_LEN);
111        let mut ask_price_builders = Vec::with_capacity(DEPTH10_LEN);
112        let mut bid_size_builders = Vec::with_capacity(DEPTH10_LEN);
113        let mut ask_size_builders = Vec::with_capacity(DEPTH10_LEN);
114        let mut bid_count_builders = Vec::with_capacity(DEPTH10_LEN);
115        let mut ask_count_builders = Vec::with_capacity(DEPTH10_LEN);
116
117        for _ in 0..DEPTH10_LEN {
118            bid_price_builders.push(FixedSizeBinaryBuilder::with_capacity(
119                data.len(),
120                PRECISION_BYTES,
121            ));
122            ask_price_builders.push(FixedSizeBinaryBuilder::with_capacity(
123                data.len(),
124                PRECISION_BYTES,
125            ));
126            bid_size_builders.push(FixedSizeBinaryBuilder::with_capacity(
127                data.len(),
128                PRECISION_BYTES,
129            ));
130            ask_size_builders.push(FixedSizeBinaryBuilder::with_capacity(
131                data.len(),
132                PRECISION_BYTES,
133            ));
134            bid_count_builders.push(UInt32Array::builder(data.len()));
135            ask_count_builders.push(UInt32Array::builder(data.len()));
136        }
137
138        let mut flags_builder = UInt8Array::builder(data.len());
139        let mut sequence_builder = UInt64Array::builder(data.len());
140        let mut ts_event_builder = UInt64Array::builder(data.len());
141        let mut ts_init_builder = UInt64Array::builder(data.len());
142
143        for depth in data {
144            for i in 0..DEPTH10_LEN {
145                bid_price_builders[i]
146                    .append_value(depth.bids[i].price.raw.to_le_bytes())
147                    .unwrap();
148                ask_price_builders[i]
149                    .append_value(depth.asks[i].price.raw.to_le_bytes())
150                    .unwrap();
151                bid_size_builders[i]
152                    .append_value(depth.bids[i].size.raw.to_le_bytes())
153                    .unwrap();
154                ask_size_builders[i]
155                    .append_value(depth.asks[i].size.raw.to_le_bytes())
156                    .unwrap();
157                bid_count_builders[i].append_value(depth.bid_counts[i]);
158                ask_count_builders[i].append_value(depth.ask_counts[i]);
159            }
160
161            flags_builder.append_value(depth.flags);
162            sequence_builder.append_value(depth.sequence);
163            ts_event_builder.append_value(depth.ts_event.as_u64());
164            ts_init_builder.append_value(depth.ts_init.as_u64());
165        }
166
167        let bid_price_arrays = bid_price_builders
168            .into_iter()
169            .map(|mut b| Arc::new(b.finish()) as Arc<dyn Array>)
170            .collect::<Vec<_>>();
171        let ask_price_arrays = ask_price_builders
172            .into_iter()
173            .map(|mut b| Arc::new(b.finish()) as Arc<dyn Array>)
174            .collect::<Vec<_>>();
175        let bid_size_arrays = bid_size_builders
176            .into_iter()
177            .map(|mut b| Arc::new(b.finish()) as Arc<dyn Array>)
178            .collect::<Vec<_>>();
179        let ask_size_arrays = ask_size_builders
180            .into_iter()
181            .map(|mut b| Arc::new(b.finish()) as Arc<dyn Array>)
182            .collect::<Vec<_>>();
183        let bid_count_arrays = bid_count_builders
184            .into_iter()
185            .map(|mut b| Arc::new(b.finish()) as Arc<dyn Array>)
186            .collect::<Vec<_>>();
187        let ask_count_arrays = ask_count_builders
188            .into_iter()
189            .map(|mut b| Arc::new(b.finish()) as Arc<dyn Array>)
190            .collect::<Vec<_>>();
191
192        let flags_array = Arc::new(flags_builder.finish()) as Arc<dyn Array>;
193        let sequence_array = Arc::new(sequence_builder.finish()) as Arc<dyn Array>;
194        let ts_event_array = Arc::new(ts_event_builder.finish()) as Arc<dyn Array>;
195        let ts_init_array = Arc::new(ts_init_builder.finish()) as Arc<dyn Array>;
196
197        let mut columns = Vec::new();
198        columns.extend(bid_price_arrays);
199        columns.extend(ask_price_arrays);
200        columns.extend(bid_size_arrays);
201        columns.extend(ask_size_arrays);
202        columns.extend(bid_count_arrays);
203        columns.extend(ask_count_arrays);
204        columns.push(flags_array);
205        columns.push(sequence_array);
206        columns.push(ts_event_array);
207        columns.push(ts_init_array);
208
209        RecordBatch::try_new(Self::get_schema(Some(metadata.clone())).into(), columns)
210    }
211
212    fn metadata(&self) -> HashMap<String, String> {
213        OrderBookDepth10::get_metadata(
214            &self.instrument_id,
215            self.bids[0].price.precision,
216            self.bids[0].size.precision,
217        )
218    }
219}
220
221impl DecodeFromRecordBatch for OrderBookDepth10 {
222    fn decode_batch(
223        metadata: &HashMap<String, String>,
224        record_batch: RecordBatch,
225    ) -> Result<Vec<Self>, EncodingError> {
226        let (instrument_id, price_precision, size_precision) = parse_metadata(metadata)?;
227        let cols = record_batch.columns();
228
229        let mut bid_prices = Vec::with_capacity(DEPTH10_LEN);
230        let mut ask_prices = Vec::with_capacity(DEPTH10_LEN);
231        let mut bid_sizes = Vec::with_capacity(DEPTH10_LEN);
232        let mut ask_sizes = Vec::with_capacity(DEPTH10_LEN);
233        let mut bid_counts = Vec::with_capacity(DEPTH10_LEN);
234        let mut ask_counts = Vec::with_capacity(DEPTH10_LEN);
235
236        macro_rules! extract_depth_column {
237            ($array:ty, $name:literal, $i:expr, $offset:expr, $type:expr) => {
238                extract_column::<$array>(cols, concat!($name, "_", stringify!($i)), $offset, $type)?
239            };
240        }
241
242        for i in 0..DEPTH10_LEN {
243            bid_prices.push(extract_depth_column!(
244                FixedSizeBinaryArray,
245                "bid_price",
246                i,
247                i,
248                DataType::FixedSizeBinary(PRECISION_BYTES)
249            ));
250            ask_prices.push(extract_depth_column!(
251                FixedSizeBinaryArray,
252                "ask_price",
253                i,
254                DEPTH10_LEN + i,
255                DataType::FixedSizeBinary(PRECISION_BYTES)
256            ));
257            bid_sizes.push(extract_depth_column!(
258                FixedSizeBinaryArray,
259                "bid_size",
260                i,
261                2 * DEPTH10_LEN + i,
262                DataType::FixedSizeBinary(PRECISION_BYTES)
263            ));
264            ask_sizes.push(extract_depth_column!(
265                FixedSizeBinaryArray,
266                "ask_size",
267                i,
268                3 * DEPTH10_LEN + i,
269                DataType::FixedSizeBinary(PRECISION_BYTES)
270            ));
271            bid_counts.push(extract_depth_column!(
272                UInt32Array,
273                "bid_count",
274                i,
275                4 * DEPTH10_LEN + i,
276                DataType::UInt32
277            ));
278            ask_counts.push(extract_depth_column!(
279                UInt32Array,
280                "ask_count",
281                i,
282                5 * DEPTH10_LEN + i,
283                DataType::UInt32
284            ));
285        }
286
287        for i in 0..DEPTH10_LEN {
288            assert_eq!(
289                bid_prices[i].value_length(),
290                PRECISION_BYTES,
291                "Price precision uses {PRECISION_BYTES} byte value"
292            );
293            assert_eq!(
294                ask_prices[i].value_length(),
295                PRECISION_BYTES,
296                "Price precision uses {PRECISION_BYTES} byte value"
297            );
298            assert_eq!(
299                bid_sizes[i].value_length(),
300                PRECISION_BYTES,
301                "Size precision uses {PRECISION_BYTES} byte value"
302            );
303            assert_eq!(
304                ask_sizes[i].value_length(),
305                PRECISION_BYTES,
306                "Size precision uses {PRECISION_BYTES} byte value"
307            );
308        }
309
310        let flags = extract_column::<UInt8Array>(cols, "flags", 6 * DEPTH10_LEN, DataType::UInt8)?;
311        let sequence =
312            extract_column::<UInt64Array>(cols, "sequence", 6 * DEPTH10_LEN + 1, DataType::UInt64)?;
313        let ts_event =
314            extract_column::<UInt64Array>(cols, "ts_event", 6 * DEPTH10_LEN + 2, DataType::UInt64)?;
315        let ts_init =
316            extract_column::<UInt64Array>(cols, "ts_init", 6 * DEPTH10_LEN + 3, DataType::UInt64)?;
317
318        // Map record batch rows to vector of OrderBookDepth10
319        let result: Result<Vec<Self>, EncodingError> = (0..record_batch.num_rows())
320            .map(|row| {
321                let mut bids = [BookOrder::default(); DEPTH10_LEN];
322                let mut asks = [BookOrder::default(); DEPTH10_LEN];
323                let mut bid_count_arr = [0u32; DEPTH10_LEN];
324                let mut ask_count_arr = [0u32; DEPTH10_LEN];
325
326                for i in 0..DEPTH10_LEN {
327                    bids[i] = BookOrder::new(
328                        OrderSide::Buy,
329                        Price::from_raw(get_raw_price(bid_prices[i].value(row)), price_precision),
330                        Quantity::from_raw(
331                            get_raw_quantity(bid_sizes[i].value(row)),
332                            size_precision,
333                        ),
334                        0, // Order id always zero
335                    );
336                    asks[i] = BookOrder::new(
337                        OrderSide::Sell,
338                        Price::from_raw(get_raw_price(ask_prices[i].value(row)), price_precision),
339                        Quantity::from_raw(
340                            get_raw_quantity(ask_sizes[i].value(row)),
341                            size_precision,
342                        ),
343                        0, // Order id always zero
344                    );
345                    bid_count_arr[i] = bid_counts[i].value(row);
346                    ask_count_arr[i] = ask_counts[i].value(row);
347                }
348
349                Ok(Self {
350                    instrument_id,
351                    bids,
352                    asks,
353                    bid_counts: bid_count_arr,
354                    ask_counts: ask_count_arr,
355                    flags: flags.value(row),
356                    sequence: sequence.value(row),
357                    ts_event: ts_event.value(row).into(),
358                    ts_init: ts_init.value(row).into(),
359                })
360            })
361            .collect();
362
363        result
364    }
365}
366
367impl DecodeDataFromRecordBatch for OrderBookDepth10 {
368    fn decode_data_batch(
369        metadata: &HashMap<String, String>,
370        record_batch: RecordBatch,
371    ) -> Result<Vec<Data>, EncodingError> {
372        let depths: Vec<Self> = Self::decode_batch(metadata, record_batch)?;
373        Ok(depths.into_iter().map(Data::from).collect())
374    }
375}
376
377////////////////////////////////////////////////////////////////////////////////
378// Tests
379////////////////////////////////////////////////////////////////////////////////
380#[cfg(test)]
381mod tests {
382    use arrow::datatypes::{DataType, Field};
383    use nautilus_model::{
384        data::stubs::stub_depth10,
385        types::{fixed::FIXED_SCALAR, price::PriceRaw, quantity::QuantityRaw},
386    };
387    use pretty_assertions::assert_eq;
388    use rstest::rstest;
389
390    use super::*;
391
392    #[rstest]
393    fn test_get_schema() {
394        let instrument_id = InstrumentId::from("AAPL.XNAS");
395        let metadata = OrderBookDepth10::get_metadata(&instrument_id, 2, 0);
396        let schema = OrderBookDepth10::get_schema(Some(metadata.clone()));
397
398        let mut group_count = 0;
399        let field_data = get_field_data();
400        for (name, data_type) in field_data {
401            for i in 0..DEPTH10_LEN {
402                let field = schema.field(i + group_count * DEPTH10_LEN).clone();
403                assert_eq!(
404                    field,
405                    Field::new(format!("{name}_{i}"), data_type.clone(), false)
406                );
407            }
408
409            group_count += 1;
410        }
411
412        let flags_field = schema.field(group_count * DEPTH10_LEN).clone();
413        assert_eq!(flags_field, Field::new("flags", DataType::UInt8, false));
414        let sequence_field = schema.field(group_count * DEPTH10_LEN + 1).clone();
415        assert_eq!(
416            sequence_field,
417            Field::new("sequence", DataType::UInt64, false)
418        );
419        let ts_event_field = schema.field(group_count * DEPTH10_LEN + 2).clone();
420        assert_eq!(
421            ts_event_field,
422            Field::new("ts_event", DataType::UInt64, false)
423        );
424        let ts_init_field = schema.field(group_count * DEPTH10_LEN + 3).clone();
425        assert_eq!(
426            ts_init_field,
427            Field::new("ts_init", DataType::UInt64, false)
428        );
429
430        assert_eq!(schema.metadata()["instrument_id"], "AAPL.XNAS");
431        assert_eq!(schema.metadata()["price_precision"], "2");
432        assert_eq!(schema.metadata()["size_precision"], "0");
433    }
434
435    #[rstest]
436    fn test_get_schema_map() {
437        let schema_map = OrderBookDepth10::get_schema_map();
438
439        let field_data = get_field_data();
440        for (name, data_type) in field_data {
441            for i in 0..DEPTH10_LEN {
442                let field = schema_map.get(&format!("{name}_{i}")).map(String::as_str);
443                assert_eq!(field, Some(format!("{data_type:?}").as_str()));
444            }
445        }
446
447        assert_eq!(schema_map.get("flags").map(String::as_str), Some("UInt8"));
448        assert_eq!(
449            schema_map.get("sequence").map(String::as_str),
450            Some("UInt64")
451        );
452        assert_eq!(
453            schema_map.get("ts_event").map(String::as_str),
454            Some("UInt64")
455        );
456        assert_eq!(
457            schema_map.get("ts_init").map(String::as_str),
458            Some("UInt64")
459        );
460    }
461
462    #[rstest]
463    fn test_encode_batch(stub_depth10: OrderBookDepth10) {
464        let instrument_id = InstrumentId::from("AAPL.XNAS");
465        let price_precision = 2;
466        let metadata = OrderBookDepth10::get_metadata(&instrument_id, price_precision, 0);
467
468        let data = vec![stub_depth10];
469        let record_batch = OrderBookDepth10::encode_batch(&metadata, &data).unwrap();
470        let columns = record_batch.columns();
471
472        assert_eq!(columns.len(), DEPTH10_LEN * 6 + 4);
473
474        // Extract and test bid prices
475        let bid_prices: Vec<_> = (0..DEPTH10_LEN)
476            .map(|i| {
477                columns[i]
478                    .as_any()
479                    .downcast_ref::<FixedSizeBinaryArray>()
480                    .unwrap()
481            })
482            .collect();
483
484        let expected_bid_prices: Vec<f64> =
485            vec![99.0, 98.0, 97.0, 96.0, 95.0, 94.0, 93.0, 92.0, 91.0, 90.0];
486
487        for (i, bid_price) in bid_prices.iter().enumerate() {
488            assert_eq!(bid_price.len(), 1);
489            assert_eq!(
490                get_raw_price(bid_price.value(0)),
491                (expected_bid_prices[i] * FIXED_SCALAR) as PriceRaw
492            );
493            assert_eq!(
494                Price::from_raw(get_raw_price(bid_price.value(0)), price_precision).as_f64(),
495                expected_bid_prices[i]
496            );
497        }
498
499        // Extract and test ask prices
500        let ask_prices: Vec<_> = (0..DEPTH10_LEN)
501            .map(|i| {
502                columns[DEPTH10_LEN + i]
503                    .as_any()
504                    .downcast_ref::<FixedSizeBinaryArray>()
505                    .unwrap()
506            })
507            .collect();
508
509        let expected_ask_prices: Vec<f64> = vec![
510            100.0, 101.0, 102.0, 103.0, 104.0, 105.0, 106.0, 107.0, 108.0, 109.0,
511        ];
512
513        for (i, ask_price) in ask_prices.iter().enumerate() {
514            assert_eq!(ask_price.len(), 1);
515            assert_eq!(
516                get_raw_price(ask_price.value(0)),
517                (expected_ask_prices[i] * FIXED_SCALAR) as PriceRaw
518            );
519            assert_eq!(
520                Price::from_raw(get_raw_price(ask_price.value(0)), price_precision).as_f64(),
521                expected_ask_prices[i]
522            );
523        }
524
525        // Extract and test bid sizes
526        let bid_sizes: Vec<_> = (0..DEPTH10_LEN)
527            .map(|i| {
528                columns[2 * DEPTH10_LEN + i]
529                    .as_any()
530                    .downcast_ref::<FixedSizeBinaryArray>()
531                    .unwrap()
532            })
533            .collect();
534
535        for (i, bid_size) in bid_sizes.iter().enumerate() {
536            assert_eq!(bid_size.len(), 1);
537            assert_eq!(
538                get_raw_quantity(bid_size.value(0)),
539                ((100.0 * FIXED_SCALAR * (i + 1) as f64) as QuantityRaw)
540            );
541        }
542
543        // Extract and test ask sizes
544        let ask_sizes: Vec<_> = (0..DEPTH10_LEN)
545            .map(|i| {
546                columns[3 * DEPTH10_LEN + i]
547                    .as_any()
548                    .downcast_ref::<FixedSizeBinaryArray>()
549                    .unwrap()
550            })
551            .collect();
552
553        for (i, ask_size) in ask_sizes.iter().enumerate() {
554            assert_eq!(ask_size.len(), 1);
555            assert_eq!(
556                get_raw_quantity(ask_size.value(0)),
557                ((100.0 * FIXED_SCALAR * ((i + 1) as f64)) as QuantityRaw)
558            );
559        }
560
561        // Extract and test bid counts
562        let bid_counts: Vec<_> = (0..DEPTH10_LEN)
563            .map(|i| {
564                columns[4 * DEPTH10_LEN + i]
565                    .as_any()
566                    .downcast_ref::<UInt32Array>()
567                    .unwrap()
568            })
569            .collect();
570
571        for count_values in bid_counts {
572            assert_eq!(count_values.len(), 1);
573            assert_eq!(count_values.value(0), 1);
574        }
575
576        // Extract and test ask counts
577        let ask_counts: Vec<_> = (0..DEPTH10_LEN)
578            .map(|i| {
579                columns[5 * DEPTH10_LEN + i]
580                    .as_any()
581                    .downcast_ref::<UInt32Array>()
582                    .unwrap()
583            })
584            .collect();
585
586        for count_values in ask_counts {
587            assert_eq!(count_values.len(), 1);
588            assert_eq!(count_values.value(0), 1);
589        }
590
591        // Test remaining fields
592        let flags_values = columns[6 * DEPTH10_LEN]
593            .as_any()
594            .downcast_ref::<UInt8Array>()
595            .unwrap();
596        let sequence_values = columns[6 * DEPTH10_LEN + 1]
597            .as_any()
598            .downcast_ref::<UInt64Array>()
599            .unwrap();
600        let ts_event_values = columns[6 * DEPTH10_LEN + 2]
601            .as_any()
602            .downcast_ref::<UInt64Array>()
603            .unwrap();
604        let ts_init_values = columns[6 * DEPTH10_LEN + 3]
605            .as_any()
606            .downcast_ref::<UInt64Array>()
607            .unwrap();
608
609        assert_eq!(flags_values.len(), 1);
610        assert_eq!(flags_values.value(0), 0);
611        assert_eq!(sequence_values.len(), 1);
612        assert_eq!(sequence_values.value(0), 0);
613        assert_eq!(ts_event_values.len(), 1);
614        assert_eq!(ts_event_values.value(0), 1);
615        assert_eq!(ts_init_values.len(), 1);
616        assert_eq!(ts_init_values.value(0), 2);
617    }
618
619    #[rstest]
620    fn test_decode_batch(stub_depth10: OrderBookDepth10) {
621        let instrument_id = InstrumentId::from("AAPL.XNAS");
622        let metadata = OrderBookDepth10::get_metadata(&instrument_id, 2, 0);
623
624        let data = vec![stub_depth10];
625        let record_batch = OrderBookDepth10::encode_batch(&metadata, &data).unwrap();
626        let decoded_data = OrderBookDepth10::decode_batch(&metadata, record_batch).unwrap();
627
628        assert_eq!(decoded_data.len(), 1);
629    }
630}