cratefield_testing/
dialect.rs

1//! The database engines a [`TestHarness`](crate::TestHarness) can run a
2//! module's tests against (issue #20): SQLite always, Postgres when the
3//! environment names a server.
4
5/// The database engine backing a test harness.
6///
7/// `Dialect::available()` is the parity entry point: a module suite
8/// loops over it so one test definition runs against every dialect the
9/// environment provides — SQLite in-memory always, Postgres 16 when
10/// `FZ_TEST_POSTGRES_URL` names a server (CI's `postgres:16` service
11/// container).
12#[derive(Debug, Clone, PartialEq, Eq)]
13pub enum Dialect {
14    /// A fresh in-memory SQLite database (the default; always
15    /// available).
16    Sqlite,
17    /// A throwaway database on the Postgres server at `url`, created
18    /// when the harness builds and dropped when it drops. Requires
19    /// building `cratefield-testing` with the `postgres` feature.
20    Postgres { url: String },
21}
22
23impl Dialect {
24    /// The lowercase engine name, for test-output tagging (`sqlite`,
25    /// `postgres`).
26    #[must_use]
27    pub fn name(&self) -> &'static str {
28        match self {
29            Dialect::Sqlite => "sqlite",
30            Dialect::Postgres { .. } => "postgres",
31        }
32    }
33
34    /// The Postgres server URL from `FZ_TEST_POSTGRES_URL` (trimmed,
35    /// non-empty), when the parity leg is available.
36    #[must_use]
37    pub fn postgres_url() -> Option<String> {
38        std::env::var("FZ_TEST_POSTGRES_URL")
39            .ok()
40            .map(|url| url.trim().to_owned())
41            .filter(|url| !url.is_empty())
42    }
43
44    /// The dialects available in this environment: always SQLite;
45    /// Postgres when `FZ_TEST_POSTGRES_URL` names a server. Prints one
46    /// notice per process when the Postgres leg is unavailable, so a
47    /// silently-skipped matrix leg is visible in the output.
48    #[must_use]
49    pub fn available() -> Vec<Self> {
50        static NOTICED: std::sync::Once = std::sync::Once::new();
51        let mut dialects = vec![Dialect::Sqlite];
52        match Self::postgres_url() {
53            Some(url) => dialects.push(Dialect::Postgres { url }),
54            None => NOTICED.call_once(|| {
55                eprintln!(
56                    "NOTE: FZ_TEST_POSTGRES_URL is not set — the Postgres parity leg is \
57                     skipped ({}); CI runs it against a postgres:16 service container",
58                    crate::POSTGRES_SKIP_REASON
59                );
60            }),
61        }
62        dialects
63    }
64}
cratefield_testing/dialect.rs

cratefield_testing/
dialect.rs
