FIX: Thread-safe response callback (#141)

Author: brian-mulier

mockfaster/src/main/java/com/decathlon/tzatziki/utils/MockFaster.java

@@ -341,7 +341,7 @@ private static class UpdatableExpectationResponseCallback implements Expectation
         private ExpectationResponseCallback callback;
 
         @Override
-        public HttpResponse handle(HttpRequest httpRequest) throws Exception {
+        public synchronized HttpResponse handle(HttpRequest httpRequest) throws Exception {
             return callback.handle(httpRequest);
         }
 

tzatziki-http/src/test/java/com/decathlon/tzatziki/steps/LocalSteps.java

@@ -1,17 +1,29 @@
 package com.decathlon.tzatziki.steps;
 
+import com.decathlon.tzatziki.utils.Asserts;
 import com.decathlon.tzatziki.utils.Comparison;
 import com.decathlon.tzatziki.utils.Guard;
 import com.decathlon.tzatziki.utils.Interaction;
 import io.cucumber.java.Before;
 import io.cucumber.java.en.Given;
+import io.cucumber.java.en.Then;
 import lombok.RequiredArgsConstructor;
 
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.stream.IntStream;
 
+import static com.decathlon.tzatziki.utils.MockFaster.target;
+import static com.decathlon.tzatziki.utils.Patterns.QUOTED_CONTENT;
+import static com.decathlon.tzatziki.utils.Unchecked.unchecked;
+import static io.restassured.RestAssured.given;
+
 @RequiredArgsConstructor
 public class LocalSteps {
     private final HttpSteps httpSteps;
+    private final ObjectSteps objects;
 
     static {
         Interaction.printResponses = true;
@@ -32,4 +44,18 @@ public void mockIdEndpointAsSeveralMocks(int startId, int endId) {
                         payload: Hello %d
                 """.formatted(idx)));
     }
+
+    @Then("getting (?:on )?" + QUOTED_CONTENT + " four times in parallel returns:$")
+    public void sendInParallel(String path, String content) {
+        ExecutorService executor = Executors.newFixedThreadPool(4);
+
+        List<CompletableFuture<Interaction.Response>> responsesAsync = List.of(
+                CompletableFuture.supplyAsync(() -> Interaction.Response.fromResponse(Interaction.Request.builder().build().send(given(), target(path), objects)), executor),
+                CompletableFuture.supplyAsync(() -> Interaction.Response.fromResponse(Interaction.Request.builder().build().send(given(), target(path), objects)), executor),
+                CompletableFuture.supplyAsync(() -> Interaction.Response.fromResponse(Interaction.Request.builder().build().send(given(), target(path), objects)), executor),
+                CompletableFuture.supplyAsync(() -> Interaction.Response.fromResponse(Interaction.Request.builder().build().send(given(), target(path), objects)), executor)
+        );
+
+        Asserts.contains(responsesAsync.stream().map(future -> unchecked(() -> future.get())).map(response -> response.body.payload).toList(), objects.resolve(content));
+    }
 }

tzatziki-http/src/test/resources/com/decathlon/tzatziki/steps/http.feature

@@ -1194,6 +1194,30 @@ Feature: to interact with an http service and setup mocks
     Then getting on "http://backend/time" returns a status 404
     Then getting on "http://backend/time" returns a status 404
 
+  Scenario: Concurrency consumption is handled properly
+    Given that "http://backend/time" is mocked as:
+      """
+      response:
+        - consumptions: 1
+          body:
+            payload: morning
+        - consumptions: 1
+          body:
+            payload: noon
+        - consumptions: 1
+          body:
+            payload: afternoon
+        - body:
+            payload: evening
+      """
+    Then getting on "http://backend/time" four times in parallel returns:
+    """
+    - morning
+    - noon
+    - afternoon
+    - evening
+    """
+
   Scenario: We can use variables from request regex into response also when using an intermediary object
     Given that response is:
     """