Refactor crate into multiple subcrates

codegen/tests/test_nested_protos.rs

@@ -0,0 +1,55 @@
+use roto_codegen::generator::generate_rust_code;
+use roto_codegen::google::protobuf::descriptor::FileDescriptorSet;
+use std::fs;
+
+#[test]
+fn test_nested_proto_generation_contains_modules() {
+    let request_path = "data/request.bin";
+    if !std::path::Path::new(request_path).exists() {
+        panic!("data/request.bin not found. This test requires the sample request binary.");
+    }
+
+    let data = fs::read(request_path).expect("Failed to read request.bin");
+
+    // The existing test logic to build a FileDescriptorSet from CodeGeneratorRequest
+    // We can simplify this by just wrapping the data if it's already a FileDescriptorSet,
+    // but request.bin is usually a CodeGeneratorRequest.
+
+    // Let's use the same logic as build_generated_code.rs to get a FileDescriptorSet
+    let request =
+        roto_codegen::google::protobuf::compiler::plugin::CodeGeneratorRequest::new(&data)
+            .expect("Failed to parse CodeGeneratorRequest");
+
+    let mut set_buf = Vec::new();
+    for file_res in request.proto_file() {
+        let (file_data, _) = file_res.expect("Failed to iterate proto_file");
+        set_buf.push(10);
+        let len = file_data.len() as u64;
+        let mut len_buf = [0u8; 10];
+        let len_size =
+            roto_runtime::write_varint(len, &mut len_buf).expect("Failed to write varint length");
+        set_buf.extend_from_slice(&len_buf[..len_size]);
+        set_buf.extend_from_slice(file_data);
+    }
+    let set = FileDescriptorSet::new(&set_buf).expect("Failed to create FileDescriptorSet");
+
+    let generated_files = generate_rust_code(&set, None, false);
+
+    let all_code: String = generated_files
+        .into_iter()
+        .map(|(_, content)| content)
+        .collect();
+    println!("Generated Code:\n{}", all_code);
+
+    // We want to see if any message has a nested module.
+    // Since we don't know exactly what's in request.bin, we'll look for ANY 'pub mod' inside the generated code
+    // that isn't at the top level (though the generator puts them inside the message definition).
+    assert!(
+        all_code.contains("pub mod "),
+        "Generated code should contain at least one nested module for nested types"
+    );
+    assert!(
+        all_code.contains("pub struct "),
+        "Generated code should contain structs"
+    );
+}