pg-embed-setup-unpriv 0.5.2

//! Shared helpers for creating partial `PostgreSQL` data directories in tests.

use std::{fs, path::Path};

/// Creates a partial data directory structure that simulates an interrupted `initdb`.
///
/// The directory will have:
/// - `PG_VERSION` file with version "16"
/// - `global/` directory (empty, no `pg_filenode.map`)
/// - `base/1/pg_class` file with dummy content
///
/// This structure is detected as invalid by the recovery logic because it
/// lacks `global/pg_filenode.map`.
///
/// # Errors
///
/// Returns an I/O error if directory or file creation fails.
///
/// # Example
///
/// ```
/// use std::path::Path;
///
/// use pg_embedded_setup_unpriv::test_support::create_partial_data_dir;
///
/// let temp = tempfile::tempdir().unwrap();
/// let data_dir = temp.path().join("data");
/// create_partial_data_dir(&data_dir).unwrap();
/// assert!(data_dir.join("PG_VERSION").exists());
/// assert!(data_dir.join("global").exists());
/// assert!(!data_dir.join("global/pg_filenode.map").exists());
/// ```
pub fn create_partial_data_dir(data_dir: &Path) -> std::io::Result<()> {
    fs::create_dir_all(data_dir.join("global"))?;
    fs::write(data_dir.join("PG_VERSION"), "16\n")?;
    fs::create_dir_all(data_dir.join("base/1"))?;
    fs::write(data_dir.join("base/1/pg_class"), "dummy")?;
    Ok(())
}

#[cfg(test)]
mod tests {
    //! Tests for partial data directory scaffolding.
    use tempfile::tempdir;

    use super::*;

    #[test]
    fn creates_expected_structure() {
        let temp = tempdir().expect("failed to create temp dir");
        let data_dir = temp.path().join("data");

        create_partial_data_dir(&data_dir).expect("failed to create partial data dir");

        assert!(data_dir.join("PG_VERSION").exists());
        assert!(data_dir.join("global").exists());
        assert!(!data_dir.join("global/pg_filenode.map").exists());
        assert!(data_dir.join("base/1/pg_class").exists());
    }
}