Simplify request body assertions (#4845)

We'll have a lot more test like these

Author: pakrym-oai

AGENTS.md

@@ -73,3 +73,28 @@ If you don’t have the tool:
 ### Test assertions
 
 - Tests should use pretty_assertions::assert_eq for clearer diffs. Import this at the top of the test module if it isn't already.
+
+### Integration tests (core)
+
+- Prefer the utilities in `core_test_support::responses` when writing end-to-end Codex tests.
+
+- All `mount_sse*` helpers return a `ResponseMock`; hold onto it so you can assert against outbound `/responses` POST bodies.
+- Use `ResponseMock::single_request()` when a test should only issue one POST, or `ResponseMock::requests()` to inspect every captured `ResponsesRequest`.
+- `ResponsesRequest` exposes helpers (`body_json`, `input`, `function_call_output`, `custom_tool_call_output`, `call_output`, `header`, `path`, `query_param`) so assertions can target structured payloads instead of manual JSON digging.
+- Build SSE payloads with the provided `ev_*` constructors and the `sse(...)`.
+
+- Typical pattern:
+
+  ```rust
+  let mock = responses::mount_sse_once(&server, responses::sse(vec![
+      responses::ev_response_created("resp-1"),
+      responses::ev_function_call(call_id, "shell", &serde_json::to_string(&args)?),
+      responses::ev_completed("resp-1"),
+  ])).await;
+
+  codex.submit(Op::UserTurn { ... }).await?;
+
+  // Assert request body if needed.
+  let request = mock.single_request();
+  // assert using request.function_call_output(call_id) or request.json_body() or other helpers.
+  ```

codex-rs/core/tests/common/responses.rs

@@ -1,11 +1,105 @@
+use std::sync::Arc;
+use std::sync::Mutex;
+
 use serde_json::Value;
 use wiremock::BodyPrintLimit;
+use wiremock::Match;
 use wiremock::Mock;
+use wiremock::MockBuilder;
 use wiremock::MockServer;
 use wiremock::Respond;
 use wiremock::ResponseTemplate;
 use wiremock::matchers::method;
-use wiremock::matchers::path;
+use wiremock::matchers::path_regex;
+
+#[derive(Debug, Clone)]
+pub struct ResponseMock {
+    requests: Arc<Mutex<Vec<ResponsesRequest>>>,
+}
+
+impl ResponseMock {
+    fn new() -> Self {
+        Self {
+            requests: Arc::new(Mutex::new(Vec::new())),
+        }
+    }
+
+    pub fn single_request(&self) -> ResponsesRequest {
+        let requests = self.requests.lock().unwrap();
+        if requests.len() != 1 {
+            panic!("expected 1 request, got {}", requests.len());
+        }
+        requests.first().unwrap().clone()
+    }
+
+    pub fn requests(&self) -> Vec<ResponsesRequest> {
+        self.requests.lock().unwrap().clone()
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct ResponsesRequest(wiremock::Request);
+
+impl ResponsesRequest {
+    pub fn body_json(&self) -> Value {
+        self.0.body_json().unwrap()
+    }
+
+    pub fn input(&self) -> Vec<Value> {
+        self.0.body_json::<Value>().unwrap()["input"]
+            .as_array()
+            .expect("input array not found in request")
+            .clone()
+    }
+
+    pub fn function_call_output(&self, call_id: &str) -> Value {
+        self.call_output(call_id, "function_call_output")
+    }
+
+    pub fn custom_tool_call_output(&self, call_id: &str) -> Value {
+        self.call_output(call_id, "custom_tool_call_output")
+    }
+
+    pub fn call_output(&self, call_id: &str, call_type: &str) -> Value {
+        self.input()
+            .iter()
+            .find(|item| {
+                item.get("type").unwrap() == call_type && item.get("call_id").unwrap() == call_id
+            })
+            .cloned()
+            .unwrap_or_else(|| panic!("function call output {call_id} item not found in request"))
+    }
+
+    pub fn header(&self, name: &str) -> Option<String> {
+        self.0
+            .headers
+            .get(name)
+            .and_then(|v| v.to_str().ok())
+            .map(str::to_string)
+    }
+
+    pub fn path(&self) -> String {
+        self.0.url.path().to_string()
+    }
+
+    pub fn query_param(&self, name: &str) -> Option<String> {
+        self.0
+            .url
+            .query_pairs()
+            .find(|(k, _)| k == name)
+            .map(|(_, v)| v.to_string())
+    }
+}
+
+impl Match for ResponseMock {
+    fn matches(&self, request: &wiremock::Request) -> bool {
+        self.requests
+            .lock()
+            .unwrap()
+            .push(ResponsesRequest(request.clone()));
+        true
+    }
+}
 
 /// Build an SSE stream body from a list of JSON events.
 pub fn sse(events: Vec<Value>) -> String {
@@ -161,34 +255,40 @@ pub fn sse_response(body: String) -> ResponseTemplate {
         .set_body_raw(body, "text/event-stream")
 }
 
-pub async fn mount_sse_once_match<M>(server: &MockServer, matcher: M, body: String)
+fn base_mock() -> (MockBuilder, ResponseMock) {
+    let response_mock = ResponseMock::new();
+    let mock = Mock::given(method("POST"))
+        .and(path_regex(".*/responses$"))
+        .and(response_mock.clone());
+    (mock, response_mock)
+}
+
+pub async fn mount_sse_once_match<M>(server: &MockServer, matcher: M, body: String) -> ResponseMock
 where
     M: wiremock::Match + Send + Sync + 'static,
 {
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .and(matcher)
+    let (mock, response_mock) = base_mock();
+    mock.and(matcher)
         .respond_with(sse_response(body))
         .up_to_n_times(1)
         .mount(server)
         .await;
+    response_mock
 }
 
-pub async fn mount_sse_once(server: &MockServer, body: String) {
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(sse_response(body))
-        .expect(1)
+pub async fn mount_sse_once(server: &MockServer, body: String) -> ResponseMock {
+    let (mock, response_mock) = base_mock();
+    mock.respond_with(sse_response(body))
+        .up_to_n_times(1)
         .mount(server)
         .await;
+    response_mock
 }
 
-pub async fn mount_sse(server: &MockServer, body: String) {
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(sse_response(body))
-        .mount(server)
-        .await;
+pub async fn mount_sse(server: &MockServer, body: String) -> ResponseMock {
+    let (mock, response_mock) = base_mock();
+    mock.respond_with(sse_response(body)).mount(server).await;
+    response_mock
 }
 
 pub async fn start_mock_server() -> MockServer {
@@ -201,7 +301,7 @@ pub async fn start_mock_server() -> MockServer {
 /// Mounts a sequence of SSE response bodies and serves them in order for each
 /// POST to `/v1/responses`. Panics if more requests are received than bodies
 /// provided. Also asserts the exact number of expected calls.
-pub async fn mount_sse_sequence(server: &MockServer, bodies: Vec<String>) {
+pub async fn mount_sse_sequence(server: &MockServer, bodies: Vec<String>) -> ResponseMock {
     use std::sync::atomic::AtomicUsize;
     use std::sync::atomic::Ordering;
 
@@ -228,10 +328,11 @@ pub async fn mount_sse_sequence(server: &MockServer, bodies: Vec<String>) {
         responses: bodies,
     };
 
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(responder)
+    let (mock, response_mock) = base_mock();
+    mock.respond_with(responder)
         .expect(num_calls as u64)
         .mount(server)
         .await;
+
+    response_mock
 }

codex-rs/core/tests/suite/cli_stream.rs

@@ -106,16 +106,12 @@ async fn exec_cli_applies_experimental_instructions_file() {
         "data: {\"type\":\"response.created\",\"response\":{}}\n\n",
         "data: {\"type\":\"response.completed\",\"response\":{\"id\":\"r1\"}}\n\n"
     );
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(
-            ResponseTemplate::new(200)
-                .insert_header("content-type", "text/event-stream")
-                .set_body_raw(sse, "text/event-stream"),
-        )
-        .expect(1)
-        .mount(&server)
-        .await;
+    let resp_mock = core_test_support::responses::mount_sse_once_match(
+        &server,
+        path("/v1/responses"),
+        sse.to_string(),
+    )
+    .await;
 
     // Create a temporary instructions file with a unique marker we can assert
     // appears in the outbound request payload.
@@ -164,8 +160,8 @@ async fn exec_cli_applies_experimental_instructions_file() {
 
     // Inspect the captured request and verify our custom base instructions were
     // included in the `instructions` field.
-    let request = &server.received_requests().await.unwrap()[0];
-    let body = request.body_json::<serde_json::Value>().unwrap();
+    let request = resp_mock.single_request();
+    let body = request.body_json();
     let instructions = body
         .get("instructions")
         .and_then(|v| v.as_str())

codex-rs/core/tests/suite/client.rs

@@ -223,15 +223,9 @@ async fn resume_includes_initial_messages_and_sends_prior_items() {
 
     // Mock server that will receive the resumed request
     let server = MockServer::start().await;
-    let first = ResponseTemplate::new(200)
-        .insert_header("content-type", "text/event-stream")
-        .set_body_raw(sse_completed("resp1"), "text/event-stream");
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(first)
-        .expect(1)
-        .mount(&server)
-        .await;
+    let resp_mock =
+        responses::mount_sse_once_match(&server, path("/v1/responses"), sse_completed("resp1"))
+            .await;
 
     // Configure Codex to resume from our file
     let model_provider = ModelProviderInfo {
@@ -277,8 +271,8 @@ async fn resume_includes_initial_messages_and_sends_prior_items() {
         .unwrap();
     wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
 
-    let request = &server.received_requests().await.unwrap()[0];
-    let request_body = request.body_json::<serde_json::Value>().unwrap();
+    let request = resp_mock.single_request();
+    let request_body = request.body_json();
     let expected_input = json!([
         {
             "type": "message",
@@ -372,18 +366,9 @@ async fn includes_base_instructions_override_in_request() {
     skip_if_no_network!();
     // Mock server
     let server = MockServer::start().await;
-
-    // First request – must NOT include `previous_response_id`.
-    let first = ResponseTemplate::new(200)
-        .insert_header("content-type", "text/event-stream")
-        .set_body_raw(sse_completed("resp1"), "text/event-stream");
-
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(first)
-        .expect(1)
-        .mount(&server)
-        .await;
+    let resp_mock =
+        responses::mount_sse_once_match(&server, path("/v1/responses"), sse_completed("resp1"))
+            .await;
 
     let model_provider = ModelProviderInfo {
         base_url: Some(format!("{}/v1", server.uri())),
@@ -414,8 +399,8 @@ async fn includes_base_instructions_override_in_request() {
 
     wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
 
-    let request = &server.received_requests().await.unwrap()[0];
-    let request_body = request.body_json::<serde_json::Value>().unwrap();
+    let request = resp_mock.single_request();
+    let request_body = request.body_json();
 
     assert!(
         request_body["instructions"]
@@ -570,16 +555,9 @@ async fn includes_user_instructions_message_in_request() {
     skip_if_no_network!();
     let server = MockServer::start().await;
 
-    let first = ResponseTemplate::new(200)
-        .insert_header("content-type", "text/event-stream")
-        .set_body_raw(sse_completed("resp1"), "text/event-stream");
-
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(first)
-        .expect(1)
-        .mount(&server)
-        .await;
+    let resp_mock =
+        responses::mount_sse_once_match(&server, path("/v1/responses"), sse_completed("resp1"))
+            .await;
 
     let model_provider = ModelProviderInfo {
         base_url: Some(format!("{}/v1", server.uri())),
@@ -610,8 +588,8 @@ async fn includes_user_instructions_message_in_request() {
 
     wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
 
-    let request = &server.received_requests().await.unwrap()[0];
-    let request_body = request.body_json::<serde_json::Value>().unwrap();
+    let request = resp_mock.single_request();
+    let request_body = request.body_json();
 
     assert!(
         !request_body["instructions"]

codex-rs/core/tests/suite/model_tools.rs

@@ -10,14 +10,11 @@ use codex_core::protocol::InputItem;
 use codex_core::protocol::Op;
 use core_test_support::load_default_config_for_test;
 use core_test_support::load_sse_fixture_with_id;
+use core_test_support::responses;
 use core_test_support::skip_if_no_network;
 use core_test_support::wait_for_event;
 use tempfile::TempDir;
-use wiremock::Mock;
 use wiremock::MockServer;
-use wiremock::ResponseTemplate;
-use wiremock::matchers::method;
-use wiremock::matchers::path;
 
 fn sse_completed(id: &str) -> String {
     load_sse_fixture_with_id("tests/fixtures/completed_template.json", id)
@@ -44,16 +41,7 @@ async fn collect_tool_identifiers_for_model(model: &str) -> Vec<String> {
     let server = MockServer::start().await;
 
     let sse = sse_completed(model);
-    let template = ResponseTemplate::new(200)
-        .insert_header("content-type", "text/event-stream")
-        .set_body_raw(sse, "text/event-stream");
-
-    Mock::given(method("POST"))
-        .and(path("/v1/responses"))
-        .respond_with(template)
-        .expect(1)
-        .mount(&server)
-        .await;
+    let resp_mock = responses::mount_sse_once_match(&server, wiremock::matchers::any(), sse).await;
 
     let model_provider = ModelProviderInfo {
         base_url: Some(format!("{}/v1", server.uri())),
@@ -93,13 +81,7 @@ async fn collect_tool_identifiers_for_model(model: &str) -> Vec<String> {
         .unwrap();
     wait_for_event(&codex, |ev| matches!(ev, EventMsg::TaskComplete(_))).await;
 
-    let requests = server.received_requests().await.unwrap();
-    assert_eq!(
-        requests.len(),
-        1,
-        "expected a single request for model {model}"
-    );
-    let body = requests[0].body_json::<serde_json::Value>().unwrap();
+    let body = resp_mock.single_request().body_json();
     tool_identifiers(&body)
 }