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/file_path_tests.rs

@@ -0,0 +1,29 @@
+use archlens_domain::FilePath;
+
+#[test]
+fn valid_file_path_is_created() {
+    let path = FilePath::new("src/main.rs").unwrap();
+    assert_eq!(path.as_str(), "src/main.rs");
+}
+
+#[test]
+fn empty_file_path_is_rejected() {
+    let result = FilePath::new("");
+    assert!(result.is_err());
+}
+
+#[test]
+fn whitespace_only_file_path_is_rejected() {
+    let result = FilePath::new("   ");
+    assert!(result.is_err());
+}
+
+#[test]
+fn file_paths_are_comparable() {
+    let a = FilePath::new("src/main.rs").unwrap();
+    let b = FilePath::new("src/main.rs").unwrap();
+    let c = FilePath::new("src/lib.rs").unwrap();
+
+    assert_eq!(a, b);
+    assert_ne!(a, c);
+}