Add retry logic to Bloop termination tests

Author: alexarchambault

modules/integration/src/test/scala/scala/cli/integration/BspTestDefinitions.scala

@@ -306,21 +306,22 @@ abstract class BspTestDefinitions(val scalaVersionOpt: Option[String])
   def testScalaTermination(
     currentBloopVersion: String,
     expectedBloopVersionAfterScalaCliRun: String
-  ) = {
-    def runBloop(args: String*) =
-      os.proc(TestUtil.cs, "launch", s"bloop-jvm:$currentBloopVersion", "--", args)
-
-    def runScalaCli(args: String*) = os.proc(TestUtil.cli, args)
-
-    runBloop("exit").call()
-    runBloop("about").call(stdout = os.Inherit, stderr = os.Inherit)
-    runScalaCli("bloop", "start", "-v", "-v", "-v").call(
-      stdout = os.Inherit,
-      stderr = os.Inherit
-    )
-    val versionLine = runBloop("about").call().out.lines()(0)
-    expect(versionLine == "bloop v" + expectedBloopVersionAfterScalaCliRun)
-  }
+  ): Unit =
+    TestUtil.retry() {
+      def runBloop(args: String*) =
+        os.proc(TestUtil.cs, "launch", s"bloop-jvm:$currentBloopVersion", "--", args)
+
+      def runScalaCli(args: String*) = os.proc(TestUtil.cli, args)
+
+      runBloop("exit").call()
+      runBloop("about").call(stdout = os.Inherit, stderr = os.Inherit)
+      runScalaCli("bloop", "start", "-v", "-v", "-v").call(
+        stdout = os.Inherit,
+        stderr = os.Inherit
+      )
+      val versionLine = runBloop("about").call().out.lines()(0)
+      expect(versionLine == "bloop v" + expectedBloopVersionAfterScalaCliRun)
+    }
 
   test("scala-cli terminates incompatible bloop") {
     testScalaTermination(Constants.oldBloopVersion, Constants.bloopVersion)

modules/integration/src/test/scala/scala/cli/integration/TestUtil.scala

@@ -4,6 +4,8 @@ import java.io.File
 import java.util.concurrent.atomic.AtomicInteger
 import java.util.concurrent.{ExecutorService, Executors, ScheduledExecutorService, ThreadFactory}
 
+import scala.annotation.tailrec
+import scala.concurrent.duration.{DurationInt, FiniteDuration}
 import scala.util.Properties
 
 object TestUtil {
@@ -81,4 +83,26 @@ object TestUtil {
   def normalizeUri(uri: String): String =
     if (uri.startsWith("file:///")) "file:/" + uri.stripPrefix("file:///")
     else uri
+
+  def retry[T](
+    maxAttempts: Int = 3,
+    waitDuration: FiniteDuration = 5.seconds
+  )(
+    run: => T
+  ): T = {
+    @tailrec
+    def helper(count: Int): T =
+      try run
+      catch {
+        case t: Throwable =>
+          if (count >= maxAttempts)
+            throw new Exception(t)
+          else {
+            System.err.println(s"Caught $t, trying again in $waitDuration…")
+            Thread.sleep(waitDuration.toMillis)
+            helper(count + 1)
+          }
+      }
+    helper(1)
+  }
 }