feat: add api test cli

README.md

@@ -33,6 +33,17 @@ cargo run
 
 The API listens on `0.0.0.0:5000` by default.
 
+## CLI helper
+
+With the API running in another terminal, call it through the small helper binary:
+
+```bash
+cargo run --bin pokedex-cli -- health
+cargo run --bin pokedex-cli -- pokemon mewtwo
+cargo run --bin pokedex-cli -- translated mewtwo
+cargo run --bin pokedex-cli -- --base-url http://localhost:5000 pokemon pikachu
+```
+
 ## Endpoints
 
 ```bash

src/bin/pokedex-cli.rs

@@ -0,0 +1,275 @@
+#![deny(warnings)]
+#![deny(clippy::all, clippy::pedantic, clippy::nursery, clippy::cargo)]
+#![allow(clippy::missing_errors_doc, clippy::multiple_crate_versions)]
+
+use std::{env, process::ExitCode, time::Duration};
+
+const DEFAULT_BASE_URL: &str = "http://localhost:5000";
+const REQUEST_TIMEOUT: Duration = Duration::from_secs(10);
+
+#[tokio::main]
+async fn main() -> ExitCode {
+    match run(env::args().skip(1)).await {
+        Ok(output) => {
+            println!("{output}");
+            ExitCode::SUCCESS
+        }
+        Err(CliError::Help) => {
+            eprintln!("{}", usage());
+            ExitCode::SUCCESS
+        }
+        Err(CliError::Usage(message)) => {
+            eprintln!("{message}\n\n{}", usage());
+            ExitCode::from(2)
+        }
+        Err(error) => {
+            eprintln!("error: {error}");
+            ExitCode::FAILURE
+        }
+    }
+}
+
+async fn run<I, S>(args: I) -> Result<String, CliError>
+where
+    I: IntoIterator<Item = S>,
+    S: Into<String>,
+{
+    let args = parse_args(args)?;
+    call_api(&args).await
+}
+
+async fn call_api(args: &CliArgs) -> Result<String, CliError> {
+    let client = reqwest::Client::builder()
+        .timeout(REQUEST_TIMEOUT)
+        .build()?;
+    let response = client.get(args.url()).send().await?;
+    let status = response.status();
+    let body = response.text().await?;
+
+    if status.is_success() {
+        pretty_body(&body)
+    } else {
+        Err(CliError::Api { status, body })
+    }
+}
+
+fn pretty_body(body: &str) -> Result<String, CliError> {
+    serde_json::from_str::<serde_json::Value>(body).map_or_else(
+        |_| Ok(body.to_owned()),
+        |value| serde_json::to_string_pretty(&value).map_err(CliError::from),
+    )
+}
+
+#[derive(Debug, Eq, PartialEq)]
+struct CliArgs {
+    base_url: String,
+    command: Command,
+}
+
+impl CliArgs {
+    fn url(&self) -> String {
+        format!("{}{}", self.base_url, self.command.path())
+    }
+}
+
+#[derive(Debug, Eq, PartialEq)]
+enum Command {
+    Health,
+    Metrics,
+    Pokemon { name: String },
+    TranslatedPokemon { name: String },
+}
+
+impl Command {
+    fn path(&self) -> String {
+        match self {
+            Self::Health => "/health".to_owned(),
+            Self::Metrics => "/metrics".to_owned(),
+            Self::Pokemon { name } => format!("/pokemon/{name}"),
+            Self::TranslatedPokemon { name } => format!("/pokemon/translated/{name}"),
+        }
+    }
+}
+
+fn parse_args<I, S>(args: I) -> Result<CliArgs, CliError>
+where
+    I: IntoIterator<Item = S>,
+    S: Into<String>,
+{
+    let mut base_url = DEFAULT_BASE_URL.to_owned();
+    let mut positional = Vec::new();
+    let mut iter = args.into_iter().map(Into::into);
+
+    while let Some(token) = iter.next() {
+        match token.as_str() {
+            "--help" | "-h" => return Err(CliError::Help),
+            "--base-url" | "-u" => {
+                base_url = iter
+                    .next()
+                    .ok_or_else(|| CliError::Usage("missing value for --base-url".to_owned()))?;
+            }
+            _ if token.starts_with('-') => {
+                return Err(CliError::Usage(format!("unknown option: {token}")));
+            }
+            _ => {
+                positional.push(token);
+                positional.extend(iter);
+                break;
+            }
+        }
+    }
+
+    Ok(CliArgs {
+        base_url: trim_base_url(&base_url),
+        command: parse_command(&positional)?,
+    })
+}
+
+fn parse_command(positional: &[String]) -> Result<Command, CliError> {
+    match positional {
+        [command] if command == "health" => Ok(Command::Health),
+        [command] if command == "metrics" => Ok(Command::Metrics),
+        [command, name] if command == "pokemon" => {
+            parse_pokemon_name(name).map(|name| Command::Pokemon {
+                name: name.to_owned(),
+            })
+        }
+        [command, name] if command == "translated" => {
+            parse_pokemon_name(name).map(|name| Command::TranslatedPokemon {
+                name: name.to_owned(),
+            })
+        }
+        [] => Err(CliError::Usage("missing command".to_owned())),
+        _ => Err(CliError::Usage("invalid command or arguments".to_owned())),
+    }
+}
+
+fn parse_pokemon_name(name: &str) -> Result<&str, CliError> {
+    if is_valid_pokemon_name(name) {
+        Ok(name)
+    } else {
+        Err(CliError::Usage(
+            "pokemon name must contain only ASCII letters, digits, or hyphens".to_owned(),
+        ))
+    }
+}
+
+fn is_valid_pokemon_name(name: &str) -> bool {
+    !name.is_empty()
+        && name
+            .bytes()
+            .all(|byte| byte.is_ascii_alphanumeric() || byte == b'-')
+}
+
+fn trim_base_url(base_url: &str) -> String {
+    base_url.trim_end_matches('/').to_owned()
+}
+
+const fn usage() -> &'static str {
+    "Usage:\n  pokedex-cli [--base-url URL] health\n  pokedex-cli [--base-url URL] metrics\n  pokedex-cli [--base-url URL] pokemon <name>\n  pokedex-cli [--base-url URL] translated <name>\n\nExamples:\n  pokedex-cli pokemon mewtwo\n  pokedex-cli translated mewtwo\n  pokedex-cli --base-url http://localhost:5000 pokemon pikachu"
+}
+
+#[derive(Debug, thiserror::Error)]
+enum CliError {
+    #[error("API returned {status}: {body}")]
+    Api {
+        status: reqwest::StatusCode,
+        body: String,
+    },
+    #[error(transparent)]
+    Http(#[from] reqwest::Error),
+    #[error(transparent)]
+    Json(#[from] serde_json::Error),
+    #[error("{0}")]
+    Usage(String),
+    #[error("help requested")]
+    Help,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{CliArgs, CliError, Command, DEFAULT_BASE_URL, parse_args, run};
+    use wiremock::{Mock, MockServer, ResponseTemplate, matchers};
+
+    #[test]
+    fn parses_default_base_url_and_pokemon_command() {
+        let args = parse_args(["pokemon", "mewtwo"]).expect("args should parse");
+
+        assert_eq!(
+            args,
+            CliArgs {
+                base_url: DEFAULT_BASE_URL.to_owned(),
+                command: Command::Pokemon {
+                    name: "mewtwo".to_owned()
+                }
+            }
+        );
+        assert_eq!(args.url(), "http://localhost:5000/pokemon/mewtwo");
+    }
+
+    #[test]
+    fn parses_custom_base_url_and_translated_command() {
+        let args = parse_args([
+            "--base-url",
+            "http://localhost:5000/",
+            "translated",
+            "mr-mime",
+        ])
+        .expect("args should parse");
+
+        assert_eq!(args.base_url, "http://localhost:5000");
+        assert_eq!(
+            args.url(),
+            "http://localhost:5000/pokemon/translated/mr-mime"
+        );
+    }
+
+    #[test]
+    fn rejects_names_that_do_not_match_the_api_contract() {
+        let error = parse_args(["pokemon", "foo?bar=baz"]).expect_err("args should fail");
+
+        assert!(matches!(error, CliError::Usage(_)));
+    }
+
+    #[tokio::test]
+    async fn calls_api_and_pretty_prints_json() {
+        let server = MockServer::start().await;
+        Mock::given(matchers::method("GET"))
+            .and(matchers::path("/pokemon/mewtwo"))
+            .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!({
+                "name": "mewtwo",
+                "isLegendary": true
+            })))
+            .expect(1)
+            .mount(&server)
+            .await;
+        let base_url = server.uri();
+
+        let output = run(["--base-url", &base_url, "pokemon", "mewtwo"])
+            .await
+            .expect("request should succeed");
+
+        assert!(output.contains("\"name\": \"mewtwo\""));
+        assert!(output.contains("\"isLegendary\": true"));
+    }
+
+    #[tokio::test]
+    async fn returns_api_errors_with_response_body() {
+        let server = MockServer::start().await;
+        Mock::given(matchers::method("GET"))
+            .and(matchers::path("/pokemon/nope"))
+            .respond_with(ResponseTemplate::new(404).set_body_json(serde_json::json!({
+                "error": "pokemon not found"
+            })))
+            .mount(&server)
+            .await;
+        let base_url = server.uri();
+
+        let error = run(["--base-url", &base_url, "pokemon", "nope"])
+            .await
+            .expect_err("request should fail");
+
+        assert!(error.to_string().contains("404"));
+        assert!(error.to_string().contains("pokemon not found"));
+    }
+}