Add protocol test helpers (#11)

[package]

name = "protocol-test-helpers"

version = "0.1.0"

authors = ["Russell Cohen <rcoh@amazon.com>"]

edition = "2018"

description = "A collection of library functions to validate HTTP requests against Smithy protocol tests"

[dependencies]

http = "0.2.1"

 No newline at end of file

use http::Request;

use std::collections::HashSet;

#[derive(Debug)]

pub enum ProtocolTestFailure {

    MissingQueryParam {

        expected: String,

        found: Vec<String>,

    },

}

pub fn validate_query_string<B>(request: &Request<B>, params: &[&str]) -> Result<(), ProtocolTestFailure> {

    let query_str = request.uri().query().unwrap_or_default();

    let request_params: HashSet<&str> = query_str.split('&').collect();

    let expected: HashSet<&str> = params.iter().copied().collect();

    for param in expected {

        if !request_params.contains(param) {

            return Err(ProtocolTestFailure::MissingQueryParam {

                expected: param.to_owned(),

                found: request_params

                    .clone()

                    .into_iter()

                    .map(|x| x.to_owned())

                    .collect(),

            });

        }

    }

    Ok(())

}

#[cfg(test)]

mod tests {

    use crate::validate_query_string;

    use http::Request;

    #[test]

    fn test_validate_empty_query_string() {

        let request = Request::builder()

            .uri("/foo")

            .body(())

            .unwrap();

        validate_query_string(&request, &vec![]).expect("no required params should pass");

        validate_query_string(&request, &vec!["a"]).err().expect("no params provided");

    }

    #[test]

    fn test_validate_query_string() {

        let request = Request::builder()

            .uri("/foo?a=b&c&d=efg&hello=a%20b")

            .body(())

            .unwrap();

        validate_query_string(&request, &vec!["a=b"]).expect("a=b is in the query string");

        validate_query_string(&request, &vec!["c", "a=b"]).expect("both params are in the query string");

        validate_query_string(&request, &vec!["a=b", "c", "d=efg", "hello=a%20b"])

            .expect("all params are in the query string");

        validate_query_string(&request, &vec![]).expect("no required params should pass");

        validate_query_string(&request, &vec!["a"]).err().expect("no parameter should match");

        validate_query_string(&request, &vec!["a=bc"]).err().expect("no parameter should match");

        validate_query_string(&request, &vec!["a=bc"]).err().expect("no parameter should match");

        validate_query_string(&request, &vec!["hell=a%20"]).err().expect("no parameter should match");

    }

}