testing with a fake client

[sbeckeriv]

rustc 1.54.0
crate version 0.13.3

I am wanting to test some retry logic. I created a fake client that proxies the request data to a function to respond per test.

    use dropbox_sdk::client_trait::{
        Endpoint, HttpClient, HttpRequestResultRaw, ParamsType, Style,
    };

    struct FakeClient {
        fake_response: fn(String, String) -> dropbox_sdk::Result<HttpRequestResultRaw>,
    }
    impl HttpClient for FakeClient {
        fn request(
            &self,
            _endpoint: Endpoint,
            _style: Style,
            function: &str,
            params: String,
            _params_type: ParamsType,
            _body: Option<&[u8]>,
            _range_start: Option<u64>,
            _range_end: Option<u64>,
        ) -> dropbox_sdk::Result<HttpRequestResultRaw> {
            // you can pass in more just update the signature.
            (self.fake_response)(function.to_string(), params)
        }
    }
    impl UserAuthClient for FakeClient {}

All of my functions have a client: &impl UserAuthClient or it could be stored on a struct if you like. I also store common JSON blobs on my fake client.

this allows me to write a test like

        let client = FakeClient {
            fake_response: |function, _params| {
                if function == "files/get_metadata" {
                    let json = FakeClient::folder_json();
                    let response = HttpRequestResultRaw {
                        result_json: json,
                        content_length: None,
                        body: None,
                    };
                    Ok(response)
                } else {
                    // untested code manually updated for code in comments below.
                    let error_string = serde_json::to_string(&CreateFolderError::Path(WriteError::Conflict(WriteConflictError::Folder))).unwrap();
                    // error creating folder 
                     let json = r#"
                    {
                      "error_summary": "path/conflict/folder/...",
                      "error": ERROR_STRING
                   
                    }"#
                    .to_string();
                    let json = json.replace("ERROR_STRING", &error_string);
                    Err(dropbox_sdk::Error::UnexpectedHttpError {
                        code: 409,
                        status: "conflict".to_string(),
                        json,
                    })
                }
            },
        };

I would personally like to see more explicit example error JSON or better JSON parsing errors. I guessed my way to a winning answer.
NetworkError("Json(Error(\"missing field `.tag`\", line: 8, column: 14))") add .tags at every level. if you are wrong you will could get NetworkError("Json(Error(\"unknown variant `write`, expected `path`\", line: 5, column: 19))") .

NetworkError("Json(Error(\"unknown field `conflict`, expected one of `malformed_path`, `conflict`, `no_write_permission`, `insufficient_space`, `disallowed_name`, `team_folder`, `operation_suppressed`, `too_many_write_operations`, `other`\", line: 8, column: 14)) I believe this means there should be a sibling node to the .tag with the same name.

Thanks for crate!

[wfraser]

Cool idea!

We're a bit limited in what exactly the text of the error message can be, because these type of errors come directly from Serde and aren't hand-written. But this isn't a scenario I've really tested, so there might be some improvements that can be made.

To avoid guesswork in what JSON text the SDK is expecting, you can make an instance of the type in question and call serde_json::to_string() on it. In your example case:

use dropbox_sdk::files::*;
println!("{}", serde_json::to_string(
    &CreateFolderError::Path(
        WriteError::Conflict(
            WriteConflictError::Folder))).unwrap());

which prints {".tag":"path","path":{".tag":"conflict","conflict":{".tag":"folder"}}}

I am interested in how you got the error "unknown field `conflict`, expected one of `malformed_path`, `conflict`, ...; that one seems wrong. Do you remember what JSON text produced that error?

[sbeckeriv]

Thanks for the bit of code! I will update to use that instead!

Searching i found this page:
https://www.dropboxforum.com/t5/Discuss-Dropbox-Developer-API/Documentation-UploadError-marked-as-open-union-is-datatype-with/td-p/467154

The error i copied was the lower one. Its wrong. its missing the .tag in path and reason isnt needed?

{
  "error_summary": "path/conflict/folder/...",                                                                                                                                      
  "error": {                                                                                                                                                                        
    ".tag": "path",                                                                                                                                                                 
    "path": {
      "reason": {                                                                                                                                                                     
        ".tag": "conflict",                                                                                                                                                           
        "conflict": {".tag": "folder"}                                                                                                                                                
      },                                                                                                                                                                              
      "upload_session_id": "AAAAAAAAVfvllHwbx7wZGA"
    }                                                                                                                                   
  }                                                                                                                                                                                 
}

this one was giving me missing .tag. so i just slapped tag in at every level. so it was something like this. now the error/path/.tag is the right spot but it doesn't have error/path/conflict which i think is what the message really means. Like i said I was guessing.

{
  "error_summary": "path/conflict/folder/...",      
   ".tag": "doesnt matter",                                                                                                                                                                                                                                                                                           
  "error": {                                                                                                                                                                        
    ".tag": "path",                                                                                                                                                                 
    "path": {
       ".tag": "conflict",                                                                                                                                                           
      "reason": {                                                                                                                                                                     
        ".tag": "conflict",                                                                                                                                                           
        "conflict": {".tag": "folder"}                                                                                                                                                
      },                                                                                                                                                                              
      "upload_session_id": "AAAAAAAAVfvllHwbx7wZGA"
    }                                                                                                                                   
  }                                                                                                                                                                                 
}