diff --git a/config_proc_macro/src/attrs.rs b/config_proc_macro/src/attrs.rs
index d8de9aae088..e7534b813d7 100644
--- a/config_proc_macro/src/attrs.rs
+++ b/config_proc_macro/src/attrs.rs
@@ -68,7 +68,11 @@ fn get_name_value_str_lit(attr: &syn::Attribute, name: &str) -> Option<String> {
     match &attr.meta {
         syn::Meta::NameValue(syn::MetaNameValue {
             path,
-            value: syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Str(lit_str), .. }),
+            value:
+                syn::Expr::Lit(syn::ExprLit {
+                    lit: syn::Lit::Str(lit_str),
+                    ..
+                }),
             ..
         }) if path.is_ident(name) => Some(lit_str.value()),
         _ => None,
diff --git a/src/test/mod.rs b/src/test/mod.rs
index d567a1b8e4e..7c563801c32 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -391,12 +391,24 @@ fn self_tests() {
         files.push(path);
     }
     // for crates that need to be included but lies outside src
-    let external_crates = vec!["check_diff"];
+    let external_crates = vec!["check_diff", "config_proc_macro"];
     for external_crate in external_crates {
         let mut path = PathBuf::from(external_crate);
         path.push("src");
-        path.push("main.rs");
-        files.push(path);
+        let directory = fs::read_dir(&path).unwrap();
+        let search_files = directory.filter_map(|file| {
+            file.ok().and_then(|f| {
+                let name = f.file_name();
+                if matches!(name.as_os_str().to_str(), Some("main.rs" | "lib.rs")) {
+                    Some(f.path())
+                } else {
+                    None
+                }
+            })
+        });
+        for file in search_files {
+            files.push(file);
+        }
     }
     files.push(PathBuf::from("src/lib.rs"));