Embedded graphs in tests and applications

Follow group membership to any depth, then the read grant, then folder contents to any depth.

MATCH (u:User {name: 'ann'})-[:MEMBER_OF*]->(:Group)-[:CAN_READ]->(top)-[:CONTAINS*0..]->(item:Doc)
RETURN DISTINCT item.name AS readable ORDER BY readable;

+----------------------+
| readable             |
+----------------------+
| "/deploy/keys.txt"   |
| "/deploy/runbook.md" |
| "/handbook.md"       |
| "/src/main.rs"       |
+----------------------+
4 rows

The same pattern walked from the document back to the users.

MATCH (d:Doc {name: '/deploy/keys.txt'})<-[:CONTAINS*0..]-(top)<-[:CAN_READ]-(:Group)<-[:MEMBER_OF*]-(u:User)
RETURN DISTINCT u.name AS user ORDER BY user;

+-------+
| user  |
+-------+
| "ann" |
| "bob" |
+-------+
2 rows

The shortest path is the explanation an audit log needs.

MATCH p = shortestPath((u:User {name: 'ann'})-[:MEMBER_OF|CAN_READ|CONTAINS*]->(d:Doc {name: '/deploy/keys.txt'}))
RETURN [n IN nodes(p) | n.name] AS because;

+----------------------------------------------------------+
| because                                                  |
+----------------------------------------------------------+
| ["ann", "on-call", "ops", "/deploy", "/deploy/keys.txt"] |
+----------------------------------------------------------+
1 row

Add the dependency from the Download page, load the dataset with include_str! and assert on the result. Cargo dependency.

use graphbuff::{params, Database};

#[test]
fn ann_may_read_the_deploy_keys() -> Result<(), Box<dyn std::error::Error>> {
    let db = Database::in_memory();
    for statement in include_str!("access.cypher").split(';') {
        if !statement.trim().is_empty() {
            db.execute(statement)?;
        }
    }

    let result = db.execute_with_params(
        "MATCH (u:User {name: $user})-[:MEMBER_OF*]->(:Group)-[:CAN_READ]->(top)
               -[:CONTAINS*0..]->(d:Doc {name: $doc})
         RETURN count(*) AS grants",
        &params! { "user" => "ann", "doc" => "/deploy/keys.txt" },
    )?;
    assert!(result.get(0, "grants").and_then(|v| v.as_int()).unwrap_or(0) > 0);
    Ok(())
}