Add CRaC lifecycle integration test scaffold

Author: adp2201

integration-tests/src/test/java/io/opentelemetry/CracLifecycleIntegrationTest.java

@@ -0,0 +1,127 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.Tracer;
+import io.opentelemetry.sdk.OpenTelemetrySdk;
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.trace.SdkTracerProvider;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Integration-style lifecycle tests for CRaC-like checkpoint/restore workflows.
+ *
+ * <p>In CRaC flows, applications typically need to close resources at checkpoint and resume normal
+ * behavior after restore.
+ */
+class CracLifecycleIntegrationTest {
+
+  @Test
+  void exportsDoNotResumeAfterShutdown_currentBehavior() {
+    LifecycleSpanExporter exporter = new LifecycleSpanExporter();
+    OpenTelemetrySdk sdk =
+        OpenTelemetrySdk.builder()
+            .setTracerProvider(
+                SdkTracerProvider.builder()
+                    .addSpanProcessor(SimpleSpanProcessor.create(exporter))
+                    .build())
+            .build();
+
+    try {
+      Tracer tracer = sdk.getTracer("crac-lifecycle-test");
+
+      emitSpan(tracer, "before-checkpoint");
+      sdk.getSdkTracerProvider().forceFlush().join(10, TimeUnit.SECONDS);
+      assertThat(exporter.exportedSpanCount()).isEqualTo(1);
+
+      sdk.getSdkTracerProvider().shutdown().join(10, TimeUnit.SECONDS);
+
+      // Simulate post-restore traffic on the same initialized SDK.
+      emitSpan(tracer, "after-restore");
+      sdk.getSdkTracerProvider().forceFlush().join(10, TimeUnit.SECONDS);
+
+      assertThat(exporter.exportedSpanCount()).isEqualTo(1);
+    } finally {
+      sdk.close();
+    }
+  }
+
+  @Test
+  @Disabled("Expected to fail until #6756 is addressed with checkpoint/restore-safe lifecycle")
+  void exportsShouldResumeAfterRestore_expectedBehavior() {
+    LifecycleSpanExporter exporter = new LifecycleSpanExporter();
+    OpenTelemetrySdk sdk =
+        OpenTelemetrySdk.builder()
+            .setTracerProvider(
+                SdkTracerProvider.builder()
+                    .addSpanProcessor(SimpleSpanProcessor.create(exporter))
+                    .build())
+            .build();
+
+    try {
+      Tracer tracer = sdk.getTracer("crac-lifecycle-test");
+
+      emitSpan(tracer, "before-checkpoint");
+      sdk.getSdkTracerProvider().forceFlush().join(10, TimeUnit.SECONDS);
+      assertThat(exporter.exportedSpanCount()).isEqualTo(1);
+
+      sdk.getSdkTracerProvider().shutdown().join(10, TimeUnit.SECONDS);
+
+      // Desired behavior for CRaC-style restore: post-restore spans should export again.
+      emitSpan(tracer, "after-restore");
+      sdk.getSdkTracerProvider().forceFlush().join(10, TimeUnit.SECONDS);
+
+      assertThat(exporter.exportedSpanCount()).isEqualTo(2);
+    } finally {
+      sdk.close();
+    }
+  }
+
+  private static void emitSpan(Tracer tracer, String name) {
+    Span span = tracer.spanBuilder(name).startSpan();
+    span.end();
+  }
+
+  private static final class LifecycleSpanExporter implements SpanExporter {
+    private final List<SpanData> exportedSpans = new ArrayList<>();
+    private boolean shutdown;
+
+    @Override
+    public CompletableResultCode export(Collection<SpanData> spans) {
+      if (shutdown) {
+        return CompletableResultCode.ofFailure();
+      }
+      exportedSpans.addAll(spans);
+      return CompletableResultCode.ofSuccess();
+    }
+
+    @Override
+    public CompletableResultCode flush() {
+      return CompletableResultCode.ofSuccess();
+    }
+
+    @Override
+    public CompletableResultCode shutdown() {
+      shutdown = true;
+      return CompletableResultCode.ofSuccess();
+    }
+
+    private int exportedSpanCount() {
+      return exportedSpans.size();
+    }
+  }
+}