Adds dedicated tests for OC shim

Per suggestion: open-telemetry/opentelemetry-java#4900 (review)

instrumentation/opencensus-shim/testing/build.gradle.kts

@@ -0,0 +1,8 @@
+plugins {
+  id("otel.javaagent-testing")
+}
+
+dependencies {
+  testLibrary("io.opentelemetry:opentelemetry-opencensus-shim")
+  testCompileOnly("io.opentelemetry:opentelemetry-api")
+}

instrumentation/opencensus-shim/testing/src/test/java/Test.java

@@ -0,0 +1,55 @@
+import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.equalTo;
+
+import io.opencensus.trace.AttributeValue;
+import io.opencensus.trace.Tracing;
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanKind;
+import io.opentelemetry.api.trace.Tracer;
+import io.opentelemetry.context.Scope;
+import io.opentelemetry.instrumentation.testing.junit.AgentInstrumentationExtension;
+import io.opentelemetry.instrumentation.testing.junit.InstrumentationExtension;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+
+public class Test {
+
+  @RegisterExtension
+  static final InstrumentationExtension testing = AgentInstrumentationExtension.create();
+
+  @org.junit.jupiter.api.Test
+  void test() {
+    Tracer tracer = testing.getOpenTelemetry().getTracer("test");
+    Span span = tracer.spanBuilder("otel-span").setSpanKind(SpanKind.INTERNAL).startSpan();
+    Scope scope = span.makeCurrent();
+    try {
+      io.opencensus.trace.Tracer ocTracer = Tracing.getTracer();
+      io.opencensus.trace.Span internal = ocTracer.spanBuilder("oc-span").startSpan();
+      io.opencensus.common.Scope ocScope = ocTracer.withSpan(internal);
+      try {
+        ocTracer
+            .getCurrentSpan()
+            .putAttribute("present-on-oc", AttributeValue.booleanAttributeValue(true));
+      } finally {
+        ocScope.close();
+      }
+      internal.end();
+    } finally {
+      scope.close();
+    }
+    span.end();
+
+    // will pass when the opencensus shim is correctly proxying calls to the ApplicationSpanImpl instance emitted by the javaagent-configured GlobalOpenTelemetry Tracer
+    testing
+        .waitAndAssertTraces(
+            traceAssert ->
+                traceAssert.hasSpansSatisfyingExactly(
+                    spanAssert -> spanAssert.hasName("otel-span").hasNoParent(),
+                    spanAssert ->
+                        spanAssert
+                            .hasName("oc-span")
+                            .hasParentSpanId(span.getSpanContext().getSpanId())
+                            .hasAttributesSatisfyingExactly(
+                                equalTo(AttributeKey.booleanKey("present-on-oc"), true))));
+  }
+}

settings.gradle.kts

@@ -357,6 +357,7 @@ hideFromDependabot(":instrumentation:okhttp:okhttp-2.2:javaagent")
 hideFromDependabot(":instrumentation:okhttp:okhttp-3.0:javaagent")
 hideFromDependabot(":instrumentation:okhttp:okhttp-3.0:library")
 hideFromDependabot(":instrumentation:okhttp:okhttp-3.0:testing")
+hideFromDependabot(":instrumentation:opencensus-shim:testing")
 hideFromDependabot(":instrumentation:opentelemetry-api:opentelemetry-api-1.0:javaagent")
 hideFromDependabot(":instrumentation:opentelemetry-api:opentelemetry-api-1.4:javaagent")
 hideFromDependabot(":instrumentation:opentelemetry-api:opentelemetry-api-1.10:javaagent")