backhopper-core 0.37.0

// Copyright (C) 2026 Michael S. Klishin and Contributors
// SPDX-License-Identifier: Apache-2.0 OR MIT
// See LICENSE-APACHE and LICENSE-MIT for details.

use backhopper_core::model::names::{MacroName, ModuleName, ProjectName, RelativePath, TagName};
use backhopper_core::model::snapshot_diff::{DiffPayload, QualifiedFunArity, WireConstantChange};

fn empty_diff() -> DiffPayload {
    DiffPayload {
        project: ProjectName::new("ra").unwrap(),
        from: TagName::new("v2.0.0").unwrap(),
        to: TagName::new("v2.1.0").unwrap(),
        modules_added: Vec::new(),
        modules_removed: Vec::new(),
        exports_added: Vec::new(),
        exports_removed: Vec::new(),
        types_added: Vec::new(),
        types_removed: Vec::new(),
        callbacks_added: Vec::new(),
        callbacks_removed: Vec::new(),
        headers_added: Vec::new(),
        headers_removed: Vec::new(),
        records_added: Vec::new(),
        records_removed: Vec::new(),
        versioned_machine_version_changes: Vec::new(),
        wire_constant_changes: Vec::new(),
    }
}

#[test]
fn is_empty_true_when_no_axis_changed() {
    assert!(empty_diff().is_empty());
}

#[test]
fn is_empty_false_when_any_axis_changed() {
    let mut d = empty_diff();
    d.modules_added.push(ModuleName::new("ra_server").unwrap());
    assert!(!d.is_empty());
}

#[test]
fn breaking_removal_count_sums_only_removed_axes() {
    let mut d = empty_diff();
    d.modules_removed.push(ModuleName::new("ra_gone").unwrap());
    d.exports_removed.push(QualifiedFunArity {
        module: ModuleName::new("ra_server").unwrap(),
        fun_arity: "start/1".parse().unwrap(),
    });
    // an added export is not a breaking removal
    d.exports_added.push(QualifiedFunArity {
        module: ModuleName::new("ra_server").unwrap(),
        fun_arity: "start/2".parse().unwrap(),
    });
    assert_eq!(d.breaking_removal_count(), 2);
}

// The name newtypes are serde-transparent: the wire form is the same bare-string JSON.
#[test]
fn name_newtypes_serialize_as_bare_strings() {
    let mut d = empty_diff();
    d.modules_added.push(ModuleName::new("ra_server").unwrap());
    let json = serde_json::to_string(&d).unwrap();
    assert!(json.contains("\"project\":\"ra\""), "{json}");
    assert!(json.contains("\"from\":\"v2.0.0\""), "{json}");
    assert!(json.contains("\"to\":\"v2.1.0\""), "{json}");
    assert!(json.contains("\"modules_added\":[\"ra_server\"]"), "{json}");
}

// `RelativePath` on headers and `MacroName` on wire-constant macros are
// the same serde-transparent contract: adding them changes no byte on
// the wire.
#[test]
fn header_and_macro_name_newtypes_serialize_as_bare_strings() {
    let mut d = empty_diff();
    d.headers_added
        .push(RelativePath::new("include/ra.hrl").unwrap());
    d.wire_constant_changes.push(WireConstantChange::Missing {
        module: ModuleName::new("ra_log_segment").unwrap(),
        side: "to".to_owned(),
        macros: vec![MacroName::new("MAGIC").unwrap()],
    });
    let json = serde_json::to_string(&d).unwrap();
    assert!(
        json.contains("\"headers_added\":[\"include/ra.hrl\"]"),
        "{json}"
    );
    assert!(json.contains("\"macros\":[\"MAGIC\"]"), "{json}");
}

#[test]
fn payload_round_trips_through_json() {
    let mut d = empty_diff();
    d.modules_removed.push(ModuleName::new("ra_gone").unwrap());
    let json = serde_json::to_string(&d).unwrap();
    let back: DiffPayload = serde_json::from_str(&json).unwrap();
    assert_eq!(back, d);
}