test(spring-boot): Tighten the Boot 3 tracing checks and use a plain test client

The unsampled-trace test now sends a request with an id of its own and
rejects any transaction for it, whatever its trace, so a mishandled
header that starts a new trace fails it. The sampled test checks that
transactions carry their request, which that relies on. The sample_rand
and deferred-sampling tests also check the envelope header's trace ID,
as the sample's tests did.

That check showed that the context's TestRestTemplate, built from the
RestTemplateBuilder Sentry customizes, added trace headers of its own
to the requests the tests sent. The suite now uses one built outside the
context.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: runningcode

sentry-spring-boot-jakarta/src/integrationTest/kotlin/io/sentry/spring/boot/jakarta/integrationtest/DistributedTracingIntegrationTest.kt

@@ -4,6 +4,7 @@ import com.google.common.truth.Truth.assertThat
 import io.sentry.SentryEnvelope
 import io.sentry.protocol.SentryId
 import io.sentry.test.transaction
+import kotlin.random.Random
 import kotlin.test.Test
 import org.springframework.http.HttpEntity
 import org.springframework.http.HttpHeaders
@@ -27,26 +28,26 @@ class DistributedTracingIntegrationTest : IntegrationTest() {
       )
     assertThat(status).isEqualTo(500)
 
-    awaitTransaction("GET /tracing/{id}", traceId)
+    val incoming = awaitTransaction("GET /tracing/{id}", traceId).transaction()!!
+    assertThat(incoming.request?.url).endsWith("/tracing/1")
     awaitTransaction("GET /person/{id}", traceId)
   }
 
   @Test
   fun `unsampled trace sends no transactions`() {
     val traceId = SentryId()
+    // An id only this request uses, because a mishandled header could start a trace of its own.
+    val id = Random.nextLong(2, Long.MAX_VALUE)
     val status =
       get(
-        "/tracing/1",
+        "/tracing/$id",
         sentryTrace = "$traceId-424cffc8f94feeee-0",
         baggage =
           "sentry-public_key=502f25099c204a2fbf4cb16edc5975d1,sentry-sample_rand=0.456789,sentry-sample_rate=0.5,sentry-sampled=false,sentry-trace_id=$traceId,sentry-transaction=HTTP%20GET",
       )
     assertThat(status).isEqualTo(500)
 
-    server.assertNoEnvelope {
-      isTransaction(it, "GET /tracing/{id}", traceId) ||
-        isTransaction(it, "GET /person/{id}", traceId)
-    }
+    server.assertNoEnvelope { isForRequest(it, id) }
   }
 
   @Test
@@ -63,6 +64,8 @@ class DistributedTracingIntegrationTest : IntegrationTest() {
 
     val incoming = awaitTransaction("GET /tracing/{id}", traceId).header.traceContext!!
     val outgoing = awaitTransaction("GET /person/{id}", traceId).header.traceContext!!
+    assertThat(incoming.traceId).isEqualTo(traceId)
+    assertThat(outgoing.traceId).isEqualTo(traceId)
     assertThat(incoming.sampleRand).isNotNull()
     assertThat(outgoing.sampleRand).isEqualTo(incoming.sampleRand)
   }
@@ -81,6 +84,8 @@ class DistributedTracingIntegrationTest : IntegrationTest() {
 
     val incoming = awaitTransaction("GET /tracing/{id}", traceId).header.traceContext!!
     val outgoing = awaitTransaction("GET /person/{id}", traceId).header.traceContext!!
+    assertThat(incoming.traceId).isEqualTo(traceId)
+    assertThat(outgoing.traceId).isEqualTo(traceId)
     assertThat(incoming.sampleRate).isNotEqualTo("0.5")
     assertThat(outgoing.sampleRate).isEqualTo(incoming.sampleRate)
   }
@@ -130,6 +135,12 @@ class DistributedTracingIntegrationTest : IntegrationTest() {
       isTransaction(it, name, traceId)
     }
 
+  /** Whether [envelope] is a transaction for `/tracing/[id]` or the `/person/[id]` it calls. */
+  private fun isForRequest(envelope: SentryEnvelope, id: Long): Boolean {
+    val url = envelope.transaction()?.request?.url ?: return false
+    return url.endsWith("/tracing/$id") || url.endsWith("/person/$id")
+  }
+
   private fun isTransaction(envelope: SentryEnvelope, name: String, traceId: SentryId): Boolean {
     val transaction = envelope.transaction() ?: return false
     return transaction.transaction == name && transaction.contexts.trace?.traceId == traceId

sentry-spring-boot-jakarta/src/integrationTest/kotlin/io/sentry/spring/boot/jakarta/integrationtest/IntegrationTest.kt

@@ -3,9 +3,10 @@ package io.sentry.spring.boot.jakarta.integrationtest
 import io.sentry.test.MockSentryServer
 import org.junit.Before
 import org.junit.runner.RunWith
-import org.springframework.beans.factory.annotation.Autowired
 import org.springframework.boot.test.context.SpringBootTest
 import org.springframework.boot.test.web.client.TestRestTemplate
+import org.springframework.boot.test.web.server.LocalServerPort
+import org.springframework.boot.web.client.RestTemplateBuilder
 import org.springframework.test.context.DynamicPropertyRegistry
 import org.springframework.test.context.DynamicPropertySource
 import org.springframework.test.context.junit4.SpringRunner
@@ -34,7 +35,13 @@ import org.springframework.test.context.junit4.SpringRunner
     ],
 )
 abstract class IntegrationTest {
-  @Autowired lateinit var restTemplate: TestRestTemplate
+  @LocalServerPort private var port = 0
+
+  // The context's TestRestTemplate comes from the RestTemplateBuilder that Sentry customizes, so
+  // it would add trace headers of its own to the requests tests send. Tests use a plain one.
+  val restTemplate: TestRestTemplate by lazy {
+    TestRestTemplate(RestTemplateBuilder().rootUri("http://localhost:$port"))
+  }
 
   @Before
   fun resetServer() {