architecturekit 0.20.2

// These tests mirror TestCheckReadOptions, TestReadEmptyRanges,
// TestReadEmptyRangesAtTheLargestRevision, TestReadEmptyRangesFromTheLatestEvent,
// TestReadOptionContradictions, and "a subject has to start with a slash" of
// TestSubjects of ArchitectureKit for Go, through check_read_options, which
// Store::read applies before it asks the database. The tests of the store show
// that it does.
//
// The options of a read are an enum per bound and order, so two lower bounds,
// two upper bounds, two orders, and an IfLatestEventIsMissing that is neither
// of its values can not be written, nor can a nil option or the zero value of
// Subjects: those tests of Go have nothing to check.

use crate::{
    Categorized, IfLatestEventIsMissing, LowerBound, Order, ReadOptions, ReadOptionsError,
    Subjects, UpperBound, check_read_options, revision::tests::NOT_REVISIONS,
};

const LARGEST_REVISION: &str = "9223372036854775807";

fn from(id: &str) -> LowerBound {
    LowerBound::FromEvent(id.to_owned())
}

fn after(id: &str) -> LowerBound {
    LowerBound::AfterEvent(id.to_owned())
}

fn up_to(id: &str) -> UpperBound {
    UpperBound::UpToEvent(id.to_owned())
}

fn before(id: &str) -> UpperBound {
    UpperBound::BeforeEvent(id.to_owned())
}

fn bounded(lower_bound: LowerBound, upper_bound: UpperBound) -> ReadOptions {
    ReadOptions {
        lower_bound,
        upper_bound,
        ..ReadOptions::default()
    }
}

fn from_latest(if_missing: IfLatestEventIsMissing) -> LowerBound {
    LowerBound::FromLatestEvent {
        subject: "/books/42".to_owned(),
        event_type: "io.thenativeweb.test.reset".to_owned(),
        if_missing,
    }
}

/// Returns the text `check_read_options` refuses the options with, or `None` if
/// it accepts them.
fn refusal_of(options: &ReadOptions) -> Option<String> {
    check_read_options(options)
        .err()
        .map(|refusal| refusal.to_string())
}

/// Every combination of the four kinds of bounds, alone and together, in
/// arrangements that leave room for an event and ones that do not, with the
/// text of the refusal, if there is one.
#[expect(
    clippy::too_many_lines,
    reason = "the table holds every combination of bounds, as the one of Go does"
)]
fn bounded_reads() -> Vec<(&'static str, ReadOptions, Option<&'static str>)> {
    use LowerBound::Unbounded as NoLowerBound;
    use UpperBound::Unbounded as NoUpperBound;

    vec![
        // A lower bound alone leaves room, since events can still come, unless
        // it is after the largest revision, which no event can ever come after.
        ("FromEvent alone", bounded(from("2"), NoUpperBound), None),
        ("AfterEvent alone", bounded(after("2"), NoUpperBound), None),
        (
            "AfterEvent of the largest revision alone",
            bounded(after(LARGEST_REVISION), NoUpperBound),
            Some(r#"empty range: no event can lie after "9223372036854775807""#),
        ),
        // An upper bound alone leaves no room only before the first event.
        (
            "UpToEvent of the first event",
            bounded(NoLowerBound, up_to("0")),
            None,
        ),
        (
            "BeforeEvent of the second event",
            bounded(NoLowerBound, before("1")),
            None,
        ),
        (
            "BeforeEvent of the first event",
            bounded(NoLowerBound, before("0")),
            Some(r#"empty range: no event can lie before "0""#),
        ),
        (
            "FromEvent and UpToEvent of the same event",
            bounded(from("1"), up_to("1")),
            None,
        ),
        (
            "FromEvent and UpToEvent in order",
            bounded(from("1"), up_to("2")),
            None,
        ),
        (
            "FromEvent and UpToEvent the wrong way round",
            bounded(from("2"), up_to("1")),
            Some(r#"empty range: no event can lie from "2" up to "1""#),
        ),
        (
            "FromEvent and BeforeEvent of the next event",
            bounded(from("1"), before("2")),
            None,
        ),
        (
            "FromEvent and BeforeEvent of the same event",
            bounded(from("1"), before("1")),
            Some(r#"empty range: no event can lie from "1" and before "1""#),
        ),
        (
            "FromEvent and BeforeEvent the wrong way round",
            bounded(from("2"), before("1")),
            Some(r#"empty range: no event can lie from "2" and before "1""#),
        ),
        (
            "FromEvent and BeforeEvent of the first event",
            bounded(from("0"), before("0")),
            Some(r#"empty range: no event can lie from "0" and before "0""#),
        ),
        (
            "AfterEvent and UpToEvent of the next event",
            bounded(after("0"), up_to("1")),
            None,
        ),
        (
            "AfterEvent and UpToEvent of the same event",
            bounded(after("1"), up_to("1")),
            Some(r#"empty range: no event can lie after "1" and up to "1""#),
        ),
        (
            "AfterEvent and UpToEvent the wrong way round",
            bounded(after("2"), up_to("1")),
            Some(r#"empty range: no event can lie after "2" and up to "1""#),
        ),
        (
            "AfterEvent and BeforeEvent with one event between them",
            bounded(after("0"), before("2")),
            None,
        ),
        (
            "AfterEvent and BeforeEvent of neighboring events",
            bounded(after("0"), before("1")),
            Some(r#"empty range: no event can lie after "0" and before "1""#),
        ),
        (
            "AfterEvent and BeforeEvent of the same event",
            bounded(after("1"), before("1")),
            Some(r#"empty range: no event can lie after "1" and before "1""#),
        ),
        (
            "AfterEvent and BeforeEvent the wrong way round",
            bounded(after("5"), before("0")),
            Some(r#"empty range: no event can lie after "5" and before "0""#),
        ),
        (
            "IDs with leading zeros, which are named as they are given",
            bounded(after("007"), before("8")),
            Some(r#"empty range: no event can lie after "007" and before "8""#),
        ),
    ]
}

#[test]
fn refuses_exactly_the_bounds_that_leave_no_room_for_an_event() {
    for (name, options, refusal) in bounded_reads() {
        assert_eq!(refusal_of(&options).as_deref(), refusal, "{name}");

        let refused = check_read_options(&options);
        if let Err(refused) = refused {
            assert!(
                matches!(refused, ReadOptionsError::EmptyRange(_)),
                "{name}: {refused:?}"
            );
            assert_eq!(
                refused.category(),
                None,
                "{name}: it belongs to no category"
            );
        }
    }
}

#[test]
fn refuses_the_same_ranges_newest_first_since_the_order_does_not_change_the_bounds() {
    for (name, options, refusal) in bounded_reads() {
        let newest_first = ReadOptions {
            order: Order::NewestFirst,
            ..options
        };

        assert_eq!(refusal_of(&newest_first).as_deref(), refusal, "{name}");
    }
}

#[test]
fn refuses_empty_ranges_at_the_largest_revision() {
    // A revision ends at 2^63-1, so the range after the largest one starts at
    // 2^63, which still fits the numbers the bounds are compared as, but which
    // no event can ever reach.
    let leading_zero = format!("0{LARGEST_REVISION}");
    for (name, options, refusal) in [
        (
            "AfterEvent alone, given with a leading zero",
            bounded(after(&leading_zero), UpperBound::Unbounded),
            Some(r#"empty range: no event can lie after "09223372036854775807""#),
        ),
        (
            "AfterEvent of the one before alone",
            bounded(after("9223372036854775806"), UpperBound::Unbounded),
            None,
        ),
        (
            "FromEvent alone",
            bounded(from(LARGEST_REVISION), UpperBound::Unbounded),
            None,
        ),
        (
            "UpToEvent alone",
            bounded(LowerBound::Unbounded, up_to(LARGEST_REVISION)),
            None,
        ),
        (
            "BeforeEvent alone",
            bounded(LowerBound::Unbounded, before(LARGEST_REVISION)),
            None,
        ),
        (
            "FromEvent and UpToEvent of it",
            bounded(from(LARGEST_REVISION), up_to(LARGEST_REVISION)),
            None,
        ),
        (
            "AfterEvent of the one before and UpToEvent of it",
            bounded(after("9223372036854775806"), up_to(LARGEST_REVISION)),
            None,
        ),
        (
            "FromEvent of the first event and UpToEvent of it",
            bounded(from("0"), up_to(LARGEST_REVISION)),
            None,
        ),
        (
            "AfterEvent and UpToEvent of it",
            bounded(after(LARGEST_REVISION), up_to(LARGEST_REVISION)),
            Some(
                r#"empty range: no event can lie after "9223372036854775807" and up to "9223372036854775807""#,
            ),
        ),
        (
            "AfterEvent and BeforeEvent of it",
            bounded(after(LARGEST_REVISION), before(LARGEST_REVISION)),
            Some(
                r#"empty range: no event can lie after "9223372036854775807" and before "9223372036854775807""#,
            ),
        ),
        (
            "FromEvent and BeforeEvent of it",
            bounded(from(LARGEST_REVISION), before(LARGEST_REVISION)),
            Some(
                r#"empty range: no event can lie from "9223372036854775807" and before "9223372036854775807""#,
            ),
        ),
        (
            "AfterEvent of it and BeforeEvent of the first event",
            bounded(after(LARGEST_REVISION), before("0")),
            Some(r#"empty range: no event can lie after "9223372036854775807" and before "0""#),
        ),
    ] {
        assert_eq!(refusal_of(&options).as_deref(), refusal, "{name}");
    }
}

#[test]
fn refuses_only_an_upper_bound_before_the_first_event_from_the_latest_event() {
    // The lower bound is only known once the database has found the latest
    // event of the type, so only an upper bound that leaves no room on its own
    // is refused.
    let latest = || from_latest(IfLatestEventIsMissing::ReadEverything);

    assert_eq!(
        refusal_of(&bounded(latest(), before("0"))).as_deref(),
        Some(r#"empty range: no event can lie before "0""#)
    );
    for upper_bound in [up_to("0"), before("1"), UpperBound::Unbounded] {
        assert_eq!(
            refusal_of(&bounded(latest(), upper_bound.clone())),
            None,
            "{upper_bound:?}"
        );
    }
}

#[test]
fn refuses_an_id_that_is_not_a_revision_for_every_bound() {
    for (name, id) in [("an empty one", "")].into_iter().chain(NOT_REVISIONS) {
        for options in [
            bounded(from(id), UpperBound::Unbounded),
            bounded(after(id), UpperBound::Unbounded),
            bounded(LowerBound::Unbounded, up_to(id)),
            bounded(LowerBound::Unbounded, before(id)),
        ] {
            let refusal = check_read_options(&options).expect_err(name);

            assert!(
                matches!(refusal, ReadOptionsError::NotARevision(_)),
                "{name}: {refusal:?}"
            );
            assert_eq!(
                refusal.to_string(),
                format!("not a revision: {id:?}"),
                "{name}"
            );
        }
    }
}

#[test]
fn refuses_the_second_bound_as_well_if_the_first_one_is_fine() {
    assert_eq!(
        refusal_of(&bounded(from("1"), before("abc"))).as_deref(),
        Some(r#"not a revision: "abc""#)
    );
}

#[test]
fn refuses_the_lower_bound_first_and_an_id_that_is_not_a_revision_before_the_range() {
    assert_eq!(
        refusal_of(&bounded(from("abc"), before("xyz"))).as_deref(),
        Some(r#"not a revision: "abc""#)
    );
    assert_eq!(
        refusal_of(&bounded(after("5"), before("xyz"))).as_deref(),
        Some(r#"not a revision: "xyz""#),
        "a range that is empty, if its bounds were revisions, is refused for the ID first"
    );
}

#[test]
fn accepts_the_options_that_leave_room_for_an_event() {
    for options in [
        ReadOptions::default(),
        bounded(from("0"), up_to("5")),
        bounded(from_latest(IfLatestEventIsMissing::ReadNothing), up_to("5")),
        ReadOptions {
            order: Order::NewestFirst,
            ..bounded(after("1"), before("5"))
        },
    ] {
        assert_eq!(refusal_of(&options), None, "{options:?}");
    }
}

#[test]
#[should_panic(
    expected = r#"architecturekit: the database reads from the latest event of a type only oldest first, but got FromLatestEvent("/books/42", "io.thenativeweb.test.reset") and NewestFirst"#
)]
fn panics_for_the_latest_event_of_a_type_newest_first() {
    let _ = check_read_options(&ReadOptions {
        lower_bound: from_latest(IfLatestEventIsMissing::ReadEverything),
        order: Order::NewestFirst,
        ..ReadOptions::default()
    });
}

#[test]
#[should_panic(
    expected = r#"architecturekit: a subject starts with a slash, which "books/42" does not"#
)]
fn panics_for_the_latest_event_on_a_subject_without_a_leading_slash() {
    let _ = check_read_options(&ReadOptions {
        lower_bound: LowerBound::FromLatestEvent {
            subject: "books/42".to_owned(),
            event_type: "io.thenativeweb.test.reset".to_owned(),
            if_missing: IfLatestEventIsMissing::ReadNothing,
        },
        ..ReadOptions::default()
    });
}

#[test]
#[should_panic(expected = "only oldest first")]
fn panics_before_it_checks_the_ids() {
    let _ = check_read_options(&ReadOptions {
        lower_bound: from_latest(IfLatestEventIsMissing::ReadEverything),
        upper_bound: before("abc"),
        order: Order::NewestFirst,
    });
}

#[test]
fn tells_a_subject_tree_from_an_exact_subject() {
    let tree = Subjects::tree("/books");
    let exact = Subjects::exact("/books");

    assert_eq!(tree.subject(), "/books");
    assert!(tree.is_tree());
    assert!(!exact.is_tree());
    assert_ne!(tree, exact);
}

#[test]
#[should_panic(
    expected = r#"architecturekit: a subject starts with a slash, which "books" does not"#
)]
fn panics_for_a_subject_tree_without_a_leading_slash() {
    let _ = Subjects::tree("books");
}

#[test]
#[should_panic(expected = r#"architecturekit: a subject starts with a slash, which "" does not"#)]
fn panics_for_an_exact_subject_without_a_leading_slash() {
    let _ = Subjects::exact("");
}