fix: require manifests for licensed gates

crates/fparkan-assets/src/lib.rs

@@ -543,10 +543,20 @@ mod tests {
     }
 
     fn fixture_root(part: &str) -> PathBuf {
-        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
-            .join("../..")
-            .join("testdata")
-            .join(part)
+        let variable = match part {
+            "IS" => "FPARKAN_CORPUS_PART1_ROOT",
+            "IS2" => "FPARKAN_CORPUS_PART2_ROOT",
+            _ => panic!("unknown licensed corpus part: {part}"),
+        };
+        let root = std::env::var_os(variable)
+            .map(PathBuf::from)
+            .unwrap_or_else(|| panic!("{variable} is required for licensed corpus tests"));
+        assert!(
+            root.is_dir(),
+            "licensed corpus root is missing: {}",
+            root.display()
+        );
+        root
     }
 
     fn repository_with_archives(