fix: update test assertions for callback-based instrumentation

- Update agent test to use AgentExecutor.workflow span name
- Fix LCEL test to handle nested JSON structure in tool input
- All tests now passing

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: nirga

packages/instrumentation-langchain/src/callback_handler.ts

@@ -130,7 +130,7 @@ export class TraceloopCallbackHandler extends BaseCallbackHandler {
       [SpanAttributes.LLM_REQUEST_TYPE]: "completion",
       [SpanAttributes.LLM_REQUEST_MODEL]: modelName,
       "traceloop.span.kind": "task",
-      "traceloop.workflow.name": runName || spanName,
+      "traceloop.workflow.name": _runName || spanName,
     });
 
     if (this.traceContent && prompts.length > 0) {

packages/instrumentation-langchain/test/instrumentation.test.ts

@@ -151,7 +151,7 @@ describe("Test Langchain instrumentation", async function () {
     });
 
     const spans = memoryExporter.getFinishedSpans();
-    const agentSpan = spans.find((span) => span.name === "langchain.agent");
+    const agentSpan = spans.find((span) => span.name === "AgentExecutor.workflow");
 
     assert.ok(result);
     assert.ok(agentSpan);
@@ -160,7 +160,7 @@ describe("Test Langchain instrumentation", async function () {
     assert.ok(agentSpan.attributes["traceloop.entity.output"]);
     assert.strictEqual(
       JSON.parse(agentSpan.attributes["traceloop.entity.input"].toString())
-        .args[0].input,
+        .input,
       "Solve `5 * (10 + 2)`",
     );
     assert.deepEqual(
@@ -351,9 +351,12 @@ describe("Test Langchain instrumentation", async function () {
     assert.strictEqual(wikipediaSpan.attributes["traceloop.span.kind"], "task");
     assert.ok(wikipediaSpan.attributes["traceloop.entity.input"]);
     assert.ok(wikipediaSpan.attributes["traceloop.entity.output"]);
+    
+    const inputData = JSON.parse(wikipediaSpan.attributes["traceloop.entity.input"].toString());
+    const toolInput = JSON.parse(inputData.args[0]);
+    
     assert.strictEqual(
-      JSON.parse(wikipediaSpan.attributes["traceloop.entity.input"].toString())
-        .args[0],
+      toolInput.input,
       '"Current Prime Minister of Malaysia" site:wikipedia.org',
     );
     assert.deepEqual(