nordisk/gunnar-ui

crates/gunnar-ui-server/tests/mcp_feature.rs

//! **The SLIM RULE for the MCP connector, held to the dependency graph**
//! (TASKS-13, owner 2026-10-25): `gunnar-mcp` is in this crate's tree ONLY
//! under the `mcp` feature. The default build does not contain it at all; the
//! routes' half of the rule is `anonymous::mcp`.
//!
//! Asked of cargo itself (`cargo tree`, offline, against this lock), because
//! the claim is about what cargo would compile, and only cargo can say that.

use std::process::Command;

fn tree(features: &[&str]) -> String {
    let cargo = std::env::var("CARGO").unwrap_or_else(|_| "cargo".to_owned());
    let manifest = concat!(env!("CARGO_MANIFEST_DIR"), "/Cargo.toml");
    let mut cmd = Command::new(cargo);
    cmd.args([
        "tree",
        "--offline",
        "--locked",
        "--manifest-path",
        manifest,
        "-p",
        "gunnar-ui-server",
        "-e",
        "normal",
        "--prefix",
        "none",
    ]);
    if !features.is_empty() {
        cmd.args(["--features", &features.join(",")]);
    }
    let out = cmd.output().expect("cargo tree runs");
    assert!(
        out.status.success(),
        "cargo tree failed: {}",
        String::from_utf8_lossy(&out.stderr)
    );
    String::from_utf8_lossy(&out.stdout).into_owned()
}

#[test]
fn the_default_build_does_not_contain_the_mcp_connector() {
    let t = tree(&[]);
    assert!(t.contains("gunnar-ui-server"), "{t}");
    assert!(
        !t.contains("gunnar-mcp"),
        "the default build links the MCP connector:\n{t}"
    );
}

#[test]
fn the_metered_build_does_not_contain_it_either() {
    assert!(!tree(&["metered"]).contains("gunnar-mcp"));
}

#[test]
fn the_mcp_build_does() {
    assert!(tree(&["mcp"]).contains("gunnar-mcp"));
}

#[test]
fn the_feature_is_off_by_default_in_the_manifest() {
    let manifest =
        std::fs::read_to_string(concat!(env!("CARGO_MANIFEST_DIR"), "/Cargo.toml")).unwrap();
    let default = manifest
        .lines()
        .find(|l| l.starts_with("default = "))
        .expect("a default line");
    assert!(!default.contains("mcp"), "{default}");
    assert!(manifest.contains("mcp = [\"dep:gunnar-mcp\", \"dep:nordisk-console-switch\"]"));
}