init: archlens — architecture diagram generator

Hex arch + DDD, tree-sitter parsing, Mermaid/ASCII output.
Supports Rust + Python. 92 tests. CI, diff, --check for staleness detection.

crates/domain/tests/code_graph_tests.rs

@@ -0,0 +1,130 @@
+use archlens_domain::{
+    CodeElement, CodeElementKind, CodeGraph, FilePath, ModuleName, Relationship, RelationshipKind,
+};
+
+fn make_element(name: &str, module: Option<&str>) -> CodeElement {
+    let mut element = CodeElement::new(
+        name,
+        CodeElementKind::Class,
+        FilePath::new(&format!("src/{name}.rs")).unwrap(),
+        1,
+    )
+    .unwrap();
+
+    if let Some(m) = module {
+        element = element.with_module(ModuleName::new(m).unwrap());
+    }
+
+    element
+}
+
+#[test]
+fn empty_graph_has_no_elements() {
+    let graph = CodeGraph::new();
+    assert!(graph.elements().is_empty());
+    assert!(graph.relationships().is_empty());
+}
+
+#[test]
+fn graph_stores_added_elements() {
+    let mut graph = CodeGraph::new();
+    graph.add_element(make_element("OrderService", None));
+    graph.add_element(make_element("Order", None));
+
+    assert_eq!(graph.elements().len(), 2);
+}
+
+#[test]
+fn graph_stores_relationships() {
+    let mut graph = CodeGraph::new();
+    let service = make_element("OrderService", None);
+    let repo = make_element("OrderRepository", None);
+
+    graph.add_element(service);
+    graph.add_element(repo);
+    graph.add_relationship(
+        Relationship::new(
+            "OrderService",
+            "OrderRepository",
+            RelationshipKind::Composition,
+        )
+        .unwrap(),
+    );
+
+    assert_eq!(graph.relationships().len(), 1);
+    let rel = &graph.relationships()[0];
+    assert_eq!(rel.source(), "OrderService");
+    assert_eq!(rel.target(), "OrderRepository");
+    assert_eq!(rel.kind(), RelationshipKind::Composition);
+}
+
+#[test]
+fn subgraph_by_module_filters_elements() {
+    let mut graph = CodeGraph::new();
+    graph.add_element(make_element("OrderService", Some("Orders")));
+    graph.add_element(make_element("Order", Some("Orders")));
+    graph.add_element(make_element("BillingService", Some("Billing")));
+
+    let module = ModuleName::new("Orders").unwrap();
+    let subgraph = graph.subgraph_by_module(&module);
+
+    assert_eq!(subgraph.elements().len(), 2);
+    assert!(
+        subgraph
+            .elements()
+            .iter()
+            .all(|e| e.module().unwrap().as_str() == "Orders")
+    );
+}
+
+#[test]
+fn subgraph_includes_relationships_within_module() {
+    let mut graph = CodeGraph::new();
+    graph.add_element(make_element("OrderService", Some("Orders")));
+    graph.add_element(make_element("Order", Some("Orders")));
+    graph.add_element(make_element("BillingService", Some("Billing")));
+
+    graph.add_relationship(
+        Relationship::new("OrderService", "Order", RelationshipKind::Composition).unwrap(),
+    );
+    graph.add_relationship(
+        Relationship::new(
+            "OrderService",
+            "BillingService",
+            RelationshipKind::Composition,
+        )
+        .unwrap(),
+    );
+
+    let module = ModuleName::new("Orders").unwrap();
+    let subgraph = graph.subgraph_by_module(&module);
+
+    assert_eq!(subgraph.relationships().len(), 1);
+    assert_eq!(subgraph.relationships()[0].target(), "Order");
+}
+
+#[test]
+fn subgraph_of_nonexistent_module_is_empty() {
+    let mut graph = CodeGraph::new();
+    graph.add_element(make_element("OrderService", Some("Orders")));
+
+    let module = ModuleName::new("Unknown").unwrap();
+    let subgraph = graph.subgraph_by_module(&module);
+
+    assert!(subgraph.elements().is_empty());
+    assert!(subgraph.relationships().is_empty());
+}
+
+#[test]
+fn graph_lists_unique_modules() {
+    let mut graph = CodeGraph::new();
+    graph.add_element(make_element("OrderService", Some("Orders")));
+    graph.add_element(make_element("Order", Some("Orders")));
+    graph.add_element(make_element("BillingService", Some("Billing")));
+    graph.add_element(make_element("Orphan", None));
+
+    let modules = graph.modules();
+    assert_eq!(modules.len(), 2);
+    assert!(modules.iter().any(|m| m.as_str() == "Orders"));
+    assert!(modules.iter().any(|m| m.as_str() == "Billing"));
+}