ChuSQL/chusql-core/storage/tests/wal_test.rs

use chusql_core_storage::protocol::Row;
use chusql_core_storage::wal::{committed_ops, Wal, WalOp};
use serde_json::json;

// WAL 测试：追加、读取、清空、截断尾巴、LSN 与提交标记。


/// 用键值对构造一行
fn row(pairs: &[(&str, serde_json::Value)]) -> Row {
    let mut m = Row::new();
    for (k, v) in pairs {
        m.insert((*k).to_string(), v.clone());
    }
    m
}

/// 三种操作写完都能原样读回
#[test]
fn append_and_read_round_trips() {
    let dir = tempfile::tempdir().unwrap();
    let wal = Wal::new(dir.path().join("wal.log"));

    let ops = [
        WalOp::Insert {
            table: "users".into(),
            row: row(&[("id", json!(1)), ("name", json!("Alice"))]),
        },
        WalOp::ReplaceAll {
            table: "users".into(),
            rows: vec![
                row(&[("id", json!(1)), ("name", json!("Alice"))]),
                row(&[("id", json!(2)), ("name", json!("Bob"))]),
            ],
        },
        WalOp::DropColumn {
            table: "users".into(),
            column: "age".into(),
            rows: vec![
                row(&[("id", json!(1)), ("name", json!("Alice"))]),
                row(&[("id", json!(2)), ("name", json!("Bob"))]),
            ],
        },
    ];
    for op in ops {
        wal.clear().unwrap();
        wal.append(&op).unwrap();
        assert_eq!(wal.read().unwrap().unwrap(), op);
    }
}

/// 文件不存在或为空都返回 None
#[test]
fn read_without_content_returns_none() {
    let dir = tempfile::tempdir().unwrap();
    let missing = Wal::new(dir.path().join("missing.log"));
    assert!(missing.read().unwrap().is_none());

    let path = dir.path().join("wal.log");
    std::fs::write(&path, b"").unwrap();
    let empty = Wal::new(&path);
    assert!(empty.read().unwrap().is_none());
}

/// 清空后读不到
#[test]
fn clear_truncates() {
    let dir = tempfile::tempdir().unwrap();
    let path = dir.path().join("wal.log");
    let wal = Wal::new(&path);

    wal.append(&WalOp::Insert {
        table: "t".into(),
        row: row(&[("id", json!(1))]),
    })
    .unwrap();
    assert!(wal.read().unwrap().is_some());

    wal.clear().unwrap();
    assert!(wal.read().unwrap().is_none());
    assert_eq!(std::fs::metadata(&path).unwrap().len(), 0);
}

/// 尾巴截断被忽略
#[test]
fn truncated_tail_is_ignored() {
    let dir = tempfile::tempdir().unwrap();
    let path = dir.path().join("wal.log");
    let wal = Wal::new(&path);

    wal.append(&WalOp::Insert {
        table: "users".into(),
        row: row(&[("id", json!(1)), ("name", json!("Alice"))]),
    })
    .unwrap();

    let full = std::fs::read(&path).unwrap();
    std::fs::write(&path, &full[..full.len() - 5]).unwrap();

    assert!(wal.read().unwrap().is_none());
}

/// 每条记录带递增的 LSN，重开也从文件里的最大号往下走
#[test]
fn every_record_gets_an_increasing_lsn() {
    let dir = tempfile::tempdir().unwrap();
    let path = dir.path().join("wal.log");
    let wal = Wal::new(&path);

    for id in 1..=3 {
        wal.append(&WalOp::Insert {
            table: "t".into(),
            row: row(&[("id", json!(id))]),
        })
        .unwrap();
    }
    let scan = wal.read_all().unwrap();
    let lsns: Vec<u64> = scan.records.iter().map(|(lsn, _)| *lsn).collect();
    assert_eq!(lsns, vec![1, 2, 3]);
    assert_eq!(scan.good_len as u64, std::fs::metadata(&path).unwrap().len());

    let reopened = Wal::new(&path);
    reopened
        .append(&WalOp::Insert {
            table: "t".into(),
            row: row(&[("id", json!(4))]),
        })
        .unwrap();
    assert_eq!(reopened.read_all().unwrap().records.last().unwrap().0, 4);
}

/// 一组操作写完带提交标记，标记的 LSN 也在记录里
#[test]
fn append_group_writes_a_commit_marker() {
    let dir = tempfile::tempdir().unwrap();
    let wal = Wal::new(dir.path().join("wal.log"));

    let group = [
        WalOp::InsertBatch {
            table: "t".into(),
            rows: vec![row(&[("id", json!(2))])],
        },
        WalOp::DeleteKeys {
            table: "t".into(),
            keys: vec![1],
        },
    ];
    let commit_lsn = wal.append_group(&group).unwrap();

    let scan = wal.read_all().unwrap();
    assert_eq!(scan.records.len(), 3);
    assert_eq!(scan.records.last().unwrap().1, WalOp::Commit);
    assert_eq!(scan.records.last().unwrap().0, commit_lsn);
    assert_eq!(wal.read().unwrap().unwrap(), group[0]);
    assert_eq!(
        committed_ops(&scan.records),
        vec![(1, group[0].clone()), (2, group[1].clone())]
    );
}

/// 没有提交标记的记录组算未提交，旧格式的单条仍算已提交
#[test]
fn records_without_a_commit_marker_stay_uncommitted() {
    let dir = tempfile::tempdir().unwrap();
    let wal = Wal::new(dir.path().join("wal.log"));

    for id in 1..=2 {
        wal.append(&WalOp::Insert {
            table: "t".into(),
            row: row(&[("id", json!(id))]),
        })
        .unwrap();
    }
    assert!(committed_ops(&wal.read_all().unwrap().records).is_empty());

    wal.clear().unwrap();
    wal.append(&WalOp::Insert {
        table: "t".into(),
        row: row(&[("id", json!(9))]),
    })
    .unwrap();
    assert_eq!(committed_ops(&wal.read_all().unwrap().records).len(), 1);
}

/// 撕成两半的尾巴能读出完好长度并截掉
#[test]
fn trailing_torn_frame_can_be_truncated() {
    let dir = tempfile::tempdir().unwrap();
    let path = dir.path().join("wal.log");
    let wal = Wal::new(&path);

    for id in 1..=2 {
        wal.append(&WalOp::Insert {
            table: "t".into(),
            row: row(&[("id", json!(id))]),
        })
        .unwrap();
    }
    let full = std::fs::read(&path).unwrap();
    std::fs::write(&path, &full[..full.len() - 3]).unwrap();

    let scan = wal.read_all().unwrap();
    assert_eq!(scan.records.len(), 1);
    assert!(scan.good_len < full.len() - 3);

    wal.truncate_to(scan.good_len).unwrap();
    assert_eq!(std::fs::metadata(&path).unwrap().len(), scan.good_len as u64);
    assert_eq!(wal.read_all().unwrap().records.len(), 1);
}

/// 检查点写读一致
#[test]
fn checkpoint_round_trips() {
    let dir = tempfile::tempdir().unwrap();
    let wal = Wal::new(dir.path().join("wal.log"));

    assert_eq!(wal.read_checkpoint().unwrap(), None);
    wal.write_checkpoint(7).unwrap();
    assert_eq!(wal.read_checkpoint().unwrap(), Some(7));
}