fix: include saveArtifact invocations in event chain

core/src/main/java/com/google/adk/runner/Runner.java

@@ -312,6 +312,7 @@ private Single<Event> appendNewMessageToSession(
       throw new IllegalArgumentException("No parts in the new_message.");
     }
 
+    Completable saveArtifactsFlow = Completable.complete();
     if (this.artifactService != null && saveInputBlobsAsArtifacts) {
       // The runner directly saves the artifacts (if applicable) in the user message and replaces
       // the artifact data with a file name placeholder.
@@ -321,9 +322,11 @@ private Single<Event> appendNewMessageToSession(
           continue;
         }
         String fileName = "artifact_" + invocationContext.invocationId() + "_" + i;
-        var unused =
-            this.artifactService.saveArtifact(
-                this.appName, session.userId(), session.id(), fileName, part);
+        saveArtifactsFlow =
+            saveArtifactsFlow.andThen(
+                this.artifactService
+                    .saveArtifact(this.appName, session.userId(), session.id(), fileName, part)
+                    .ignoreElement());
 
         newMessage
             .parts()
@@ -348,7 +351,8 @@ private Single<Event> appendNewMessageToSession(
           EventActions.builder().stateDelta(new ConcurrentHashMap<>(stateDelta)).build());
     }
 
-    return this.sessionService.appendEvent(session, eventBuilder.build());
+    return saveArtifactsFlow.andThen(
+        this.sessionService.appendEvent(session, eventBuilder.build()));
   }
 
   /** See {@link #runAsync(String, String, Content, RunConfig, Map)}. */

core/src/test/java/com/google/adk/runner/RunnerTest.java

@@ -24,6 +24,8 @@
 import static com.google.adk.testing.TestUtils.createTextLlmResponse;
 import static com.google.adk.testing.TestUtils.simplifyEvents;
 import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Arrays.stream;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.CALLS_REAL_METHODS;
 import static org.mockito.Mockito.mock;
@@ -36,6 +38,7 @@
 import com.google.adk.agents.LlmAgent;
 import com.google.adk.agents.RunConfig;
 import com.google.adk.apps.App;
+import com.google.adk.artifacts.BaseArtifactService;
 import com.google.adk.events.Event;
 import com.google.adk.flows.llmflows.Functions;
 import com.google.adk.models.LlmResponse;
@@ -62,19 +65,22 @@
 import io.reactivex.rxjava3.core.Completable;
 import io.reactivex.rxjava3.core.Flowable;
 import io.reactivex.rxjava3.core.Maybe;
+import io.reactivex.rxjava3.core.Single;
 import io.reactivex.rxjava3.subscribers.TestSubscriber;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.atomic.AtomicInteger;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
 import org.mockito.ArgumentCaptor;
+import org.mockito.Mockito;
 
 @RunWith(JUnit4.class)
 public final class RunnerTest {
@@ -846,6 +852,19 @@ private Content createContent(String text) {
     return Content.builder().parts(Part.builder().text(text).build()).build();
   }
 
+  private static Content createInlineDataContent(byte[]... data) {
+    return Content.builder()
+        .parts(
+            stream(data)
+                .map(dataBytes -> Part.fromBytes(dataBytes, "example/octet-stream"))
+                .toArray(Part[]::new))
+        .build();
+  }
+
+  private static Content createInlineDataContent(String... data) {
+    return createInlineDataContent(stream(data).map(d -> d.getBytes(UTF_8)).toArray(byte[][]::new));
+  }
+
   @Test
   public void runAsync_createsInvocationSpan() {
     var unused =
@@ -1203,4 +1222,40 @@ public static ImmutableMap<String, Object> echoTool(String message) {
       return ImmutableMap.of("message", message);
     }
   }
+
+  @Test
+  public void runner_executesSaveArtifactFlow() {
+    // arrange
+    final AtomicInteger artifactsSavedCounter = new AtomicInteger();
+    BaseArtifactService mockArtifactService = Mockito.mock(BaseArtifactService.class);
+    when(mockArtifactService.saveArtifact(any(), any(), any(), any(), any()))
+        .thenReturn(
+            Single.defer(
+                () -> {
+                  // we want to assert not only that the saveArtifact method was
+                  // called, but also that the flow that it returned was run, so
+                  // we need to record the call in a counter
+                  artifactsSavedCounter.incrementAndGet();
+                  return Single.just(42);
+                }));
+    Runner runner =
+        Runner.builder()
+            .app(App.builder().name("test").rootAgent(agent).build())
+            .artifactService(mockArtifactService)
+            .build();
+    session = runner.sessionService().createSession("test", "user").blockingGet();
+    // each inline data will be saved using our mock artifact service
+    Content content = createInlineDataContent("test data", "test data 2");
+    RunConfig runConfig = RunConfig.builder().setSaveInputBlobsAsArtifacts(true).build();
+
+    // act
+    var events = runner.runAsync("user", session.id(), content, runConfig).test();
+
+    // assert
+    events.assertComplete();
+    // artifacts where saved
+    assertThat(artifactsSavedCounter.get()).isEqualTo(2);
+    // agent was run
+    assertThat(simplifyEvents(events.values())).containsExactly("test agent: from llm");
+  }
 }