fix: improve http error details

src/error.rs

@@ -2,6 +2,8 @@ use std::convert::From;
 use std::error;
 use std::fmt;
 
+use reqwest::StatusCode;
+
 /// Wraps several types of errors.
 #[derive(Debug)]
 pub struct Error {
@@ -22,6 +24,13 @@ impl Error{
             msg
         }
     }
+
+    pub fn http(status: StatusCode, body: String) -> Error {
+        Error {
+            kind: ErrorKind::FlagsmithAPIError,
+            msg: format!("HTTP Api error: {status}, {body}")
+        }
+    }
 }
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -51,3 +60,26 @@ impl  From<serde_json::Error> for Error {
         Error::new(ErrorKind::FlagsmithAPIError, e.to_string())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_http_error_includes_status_and_body() {
+        let error = Error::http(
+            StatusCode::BAD_GATEWAY,
+            "{\"detail\":\"upstream unavailable\"}".to_string(),
+        );
+
+        assert_eq!(error.kind, ErrorKind::FlagsmithAPIError);
+        assert_eq!(
+            error.msg,
+            "HTTP Api error: 502 Bad Gateway, {\"detail\":\"upstream unavailable\"}"
+        );
+        assert_eq!(
+            error.to_string(),
+            "Flagsmith API error: HTTP Api error: 502 Bad Gateway, {\"detail\":\"upstream unavailable\"}"
+        );
+    }
+}

src/flagsmith/mod.rs

@@ -434,13 +434,11 @@ fn get_json_response(
         request = request.body(body.unwrap());
     };
     let response = request.send()?;
-    if response.status().is_success() {
+    let status = response.status();
+    if status.is_success() {
         return Ok(response.json()?);
     } else {
-        return Err(error::Error::new(
-            error::ErrorKind::FlagsmithAPIError,
-            response.text()?,
-        ));
+        return Err(error::Error::http(status, response.text()?));
     }
 }
 

tests/integration_test.rs

@@ -713,7 +713,8 @@ fn test_flagsmith_api_error_is_returned_if_something_goes_wrong_with_the_request
         when.method(GET)
             .path("/api/v1/flags/")
             .header("X-Environment-Key", ENVIRONMENT_KEY);
-        then.status(502).json_body({}); // returning 502
+        then.status(502)
+            .json_body(serde_json::json!({"detail": "bad gateway"})); // returning 502
     });
     let url = mock_server.url("/api/v1/");
     let flagsmith_options = FlagsmithOptions {
@@ -724,7 +725,11 @@ fn test_flagsmith_api_error_is_returned_if_something_goes_wrong_with_the_request
 
     // When
     let err = flagsmith.get_environment_flags().err().unwrap();
+
+    // Then: the error carries the HTTP status and the response body
     assert_eq!(err.kind, flagsmith::error::ErrorKind::FlagsmithAPIError);
+    assert!(err.msg.contains("502 Bad Gateway"), "unexpected msg: {}", err.msg);
+    assert!(err.msg.contains("bad gateway"), "unexpected msg: {}", err.msg);
 }
 
 #[rstest]