Retry docs' tests on the CI (#3618)

Author: Gedochao

modules/docs-tests/src/test/scala/sclicheck/DocTests.scala

@@ -38,7 +38,7 @@ class DocTests extends munit.FunSuite {
     md <- inputs
   }
     test(s"$tpe ${md.toString.stripSuffix(".md")}") {
-      checkFile(dir / md, options)
+      TestUtil.retryOnCi()(checkFile(dir / md, options))
     }
 
 }

modules/docs-tests/src/test/scala/sclicheck/TestUtil.scala

@@ -1,6 +1,10 @@
 package sclicheck
 
+import scala.annotation.tailrec
+import scala.concurrent.duration.{DurationInt, FiniteDuration}
+
 object TestUtil {
+  val isCI: Boolean = System.getenv("CI") != null
 
   def withTmpDir[T](prefix: String)(f: os.Path => T): T = {
     val tmpDir = os.temp.dir(prefix = prefix)
@@ -20,4 +24,36 @@ object TestUtil {
       sys.error("SCLICHECK_SCALA_CLI not set")
     }
 
+  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) {
+            System.err.println(s"$maxAttempts attempts failed, caught $t. Giving up.")
+            throw new Exception(t)
+          }
+          else {
+            val remainingAttempts = maxAttempts - count
+            System.err.println(
+              s"Caught $t, $remainingAttempts attempts remaining, trying again in $waitDuration…"
+            )
+            Thread.sleep(waitDuration.toMillis)
+            System.err.println(s"Trying attempt $count out of $maxAttempts...")
+            helper(count + 1)
+          }
+      }
+
+    helper(1)
+  }
+
+  def retryOnCi[T](maxAttempts: Int = 3, waitDuration: FiniteDuration = 5.seconds)(
+    run: => T
+  ): T = retry(if (isCI) maxAttempts else 1, waitDuration)(run)
 }