Fix flaky Gradle Daemon instrumentation smoke test (#8955)

Author: nikita-tkachenko-datadog

dd-smoke-tests/gradle/src/test/groovy/datadog/smoketest/GradleDaemonSmokeTest.groovy

@@ -50,7 +50,7 @@ class GradleDaemonSmokeTest extends AbstractGradleTest {
 
     where:
     gradleVersion | projectName                                        | successExpected | expectedTraces | expectedCoverages
-    "3.0"         | "test-succeed-old-gradle"                          | true            | 5              | 1
+    "3.5"         | "test-succeed-old-gradle"                          | true            | 5              | 1
     "7.6.4"       | "test-succeed-legacy-instrumentation"              | true            | 5              | 1
     "7.6.4"       | "test-succeed-multi-module-legacy-instrumentation" | true            | 7              | 2
     "7.6.4"       | "test-succeed-multi-forks-legacy-instrumentation"  | true            | 6              | 2
@@ -244,6 +244,7 @@ class GradleDaemonSmokeTest extends AbstractGradleTest {
       .withProjectDir(projectFolder.toFile())
       .withGradleVersion(gradleVersion)
       .withArguments(arguments)
+      .withEnvironment(["GRADLE_VERSION": gradleVersion])
       .forwardOutput()
 
     println "${new Date()}: $specificationContext.currentIteration.displayName - Starting Gradle run"

dd-smoke-tests/gradle/src/test/resources/test-succeed-gradle-plugin-test/coverages.ftl

@@ -1,9 +1,9 @@
 [ {
   "files" : [ {
-    "bitmap" : "AAAAx98=",
+    "bitmap" : "AAAAx+EN",
     "filename" : "src/test/java/datadog/smoke/HelloPluginFunctionalTest.java"
   } ],
   "span_id" : ${content_span_id_4},
   "test_session_id" : ${content_test_session_id},
   "test_suite_id" : ${content_test_suite_id}
-} ]
+} ]

dd-smoke-tests/gradle/src/test/resources/test-succeed-gradle-plugin-test/events.ftl

@@ -215,7 +215,7 @@
       "_dd.profiling.enabled" : 0,
       "_dd.trace_span_attribute_schema" : 0,
       "process_id" : ${content_metrics_process_id_2},
-      "test.source.end" : 40,
+      "test.source.end" : 44,
       "test.source.start" : 16
     },
     "name" : "junit5.test_suite",
@@ -273,7 +273,7 @@
       "_dd.profiling.enabled" : 0,
       "_dd.trace_span_attribute_schema" : 0,
       "process_id" : ${content_metrics_process_id_2},
-      "test.source.end" : 39,
+      "test.source.end" : 43,
       "test.source.start" : 30
     },
     "name" : "junit5.test",
@@ -464,4 +464,4 @@
   },
   "type" : "span",
   "version" : 1
-} ]
+} ]

dd-smoke-tests/gradle/src/test/resources/test-succeed-gradle-plugin-test/src/test/java/datadog/smoke/HelloPluginFunctionalTest.java

@@ -30,7 +30,11 @@ void pluginPrintsHelloMessageOnGradle85() {
     BuildResult result = GradleRunner.create()
         .withProjectDir(testProjectDir.toFile())
         .withPluginClasspath()
-        .withGradleVersion("8.5")
+        // Use the same Gradle version as of the actual smoke test that builds this project.
+        // This is to ensure Gradle is already downloaded and available in the environment.
+        // Gradle Test Kit can download a Gradle distribution by itself,
+        // but sometimes these downloads fail, making the test flaky.
+        .withGradleVersion(System.getenv("GRADLE_VERSION"))
         .withArguments("hello", "--stacktrace")
         .forwardOutput()
         .build();