Use ChiselStage in Tests

This migrates the tests to Chisel 3.4/FIRRTL 1.4. This primarily
involves removing usages of deprecated methods including:

- Remove usages of Driver
- Use ChiselStage methods instead of BackendCompilationUtilities
  methods
- Use Dependency API for custom transforms
- Use extractCause to unpack StackError

Signed-off-by: Schuyler Eldridge <schuyler.eldridge@ibm.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/test/scala/chiselTests/DecoupledSpec.scala b/src/test/scala/chiselTests/DecoupledSpec.scala
index c251df82..78c8458d 100644
--- a/src/test/scala/chiselTests/DecoupledSpec.scala
+++ b/src/test/scala/chiselTests/DecoupledSpec.scala
@@ -3,11 +3,12 @@
 package chiselTests
 
 import chisel3._
+import chisel3.stage.ChiselStage
 import chisel3.util.Decoupled
 
 class DecoupledSpec extends ChiselFlatSpec {
   "Decoupled() and Decoupled.empty" should "give DecoupledIO with empty payloads" in {
-    elaborate(new Module {
+    ChiselStage.elaborate(new Module {
       val io = IO(new Bundle {
         val in = Flipped(Decoupled())
         val out = Decoupled.empty