clean up future handling

src/test/scala/cromwell/engine/db/slick/SlickDataAccessSpec.scala

@@ -222,11 +222,16 @@ class SlickDataAccessSpec extends FlatSpec with Matchers with ScalaFutures {
     }
 
     def assertCallCachingFailure(id: WorkflowId, callName: Option[String], messages: String*): Future[Unit] = {
-      // The `from` Future is expected to fail, so if the `map` block runs the test should fail.  `recover` the
-      // failed Future and assert all the expected messages are present in the exception text and the correct number
-      // of expected failures are seen.
-      CallCachingParameters.from(id, None, AllowFalse, dataAccess) map {
-        s => throw new RuntimeException(s"Unexpected success: $s") } recover {
+      // The `from` Future is expected to fail, so if the forcomp actually runs the test should fail.
+      val parameters = for {
+        s <- CallCachingParameters.from(id, None, AllowFalse, dataAccess)
+      } yield throw new RuntimeException(s"Unexpected success: $s")
+
+      // `recover` the failed Future looking for an expected `IllegalArgumentException`.  Assert all the expected
+      // messages are present in the exception text and the correct number of expected failures are seen.
+      // If the `parameters` Future is failed but the exception isn't an `IllegalArgumentException` then this recover
+      // won't match and the Future will remain failed and fail the test.
+      parameters recover {
         case e: IllegalArgumentException =>
           messages foreach { m => if (!e.getMessage.contains(m)) throw new RuntimeException(s"Missing message: $m.  Exception text: ${e.getMessage}") }
           if (e.getMessage.count(_ == '\n') != messages.size - 1) throw new RuntimeException(s"Unexpected messages seen: ${e.getMessage}")