Split out TestFailedException into ScalaTest env (#27)

src/main/scala/chisel3/tester/BackendInterface.scala

@@ -4,13 +4,11 @@ package chisel3.tester
 
 import chisel3._
 import chisel3.experimental.MultiIOModule
-import org.scalatest.exceptions.TestFailedException
 
 import scala.collection.mutable
 
 class ThreadOrderDependentException(message: String) extends Exception(message)
 class TimeoutException(message: String) extends Exception(message)
-class FailedExpectException(message: String, val failedCodeStackDepth: Int) extends Exception(message)
 
 // when interfacing with the testdriver before stepping the clock after moving to an earlier region
 class TemporalParadox(message: String) extends Exception(message)
@@ -141,82 +139,3 @@ trait BackendInstance[T <: MultiIOModule] extends BackendInterface {
     */
   def run(testFn: T => Unit): Unit
 }
-
-/** Interface into the testing environment, like ScalaTest
-  */
-trait TestEnvInterface {
-
-  protected val batchedFailures: mutable.ArrayBuffer[Exception] = new mutable.ArrayBuffer
-
-  def topFileName: Option[String]
-
-  val useTestFailedException: Boolean = false
-
-  /** Logs a tester failure at this point.
-    * Failures queued until the next checkpoint.
-    */
-  def testerFail(msg: String): Unit = {
-    batchedFailures += (
-            if(useTestFailedException) {
-              new TestFailedException(msg, failedCodeStackDepth = 4)
-            }
-            else {
-              new FailedExpectException(msg, 4)
-            })
-  }
-
-  protected def getExpectDetailedTrace(trace: Seq[StackTraceElement], inFile: String): String = {
-    val fullTrace = Context().backend.getParentTraceElements ++ trace
-
-    // In the threading case, this needs to be overridden to trace through parent threads
-    val lineNumbers = fullTrace.collect {
-      case ste if ste.getFileName == inFile => ste.getLineNumber
-    }.mkString(", ")
-    if (lineNumbers.isEmpty) {
-      s" (no lines in $inFile)"
-    } else {
-      s" (lines in $inFile: $lineNumbers)"
-    }
-  }
-
-  /** Expect a specific value on a wire, calling testerFail if the expectation isn't met.
-    * Failures queued until the next checkpoint.
-    */
-  def testerExpect(expected: Any, actual: Any, signal: String, msg: Option[String]): Unit = {
-    if (expected != actual) {
-      val appendMsg = msg match {
-        case Some(_) => s": $msg"
-        case _ => ""
-      }
-
-      val trace = new Throwable
-      val expectStackDepth = trace.getStackTrace.indexWhere(ste =>
-        ste.getClassName == "chisel3.tester.package$testableData" && ste.getMethodName == "expect")
-      require(expectStackDepth != -1,
-        s"Failed to find expect in stack trace:\r\n${trace.getStackTrace.mkString("\r\n")}")
-
-      val trimmedTrace = trace.getStackTrace.drop(expectStackDepth + 2)
-      val detailedTrace = topFileName.map(getExpectDetailedTrace(trimmedTrace.toSeq, _)).getOrElse("")
-
-      val message = s"$signal=$actual did not equal expected=$expected$appendMsg$detailedTrace"
-      val stackIndex = expectStackDepth + 1
-      batchedFailures += (
-              if(useTestFailedException) {
-                new TestFailedException(message, failedCodeStackDepth = stackIndex)
-              }
-              else {
-                new FailedExpectException(message, stackIndex)
-              })
-    }
-  }
-
-  /** If there are any failures, reports them and end the test now.
-    */
-  def checkpoint(): Unit = {
-    // TODO: report multiple exceptions simultaneously
-    for (failure <- batchedFailures) {
-      throw failure
-    }
-  }
-
-}

src/main/scala/chisel3/tester/ChiselScalatestTester.scala

@@ -20,8 +20,6 @@ trait ChiselScalatestTester extends Assertions with TestSuiteMixin with TestEnvI
     }
   }
 
-  override val useTestFailedException = true
-
   // Stack trace data to help generate more informative (and localizable) failure messages
   var topFileName: Option[String] = None  // best guess at the testdriver top filename
 
@@ -38,7 +36,15 @@ trait ChiselScalatestTester extends Assertions with TestSuiteMixin with TestEnvI
 
     batchedFailures.clear()
 
-    Context.run(tester, this, testFn)
+    try {
+      Context.run(tester, this, testFn)
+    } catch {
+      // Translate testers2's FailedExpectException into ScalaTest TestFailedException that is more readable
+      case exc: FailedExpectException =>
+        val newExc = new TestFailedException(exc, exc.failedCodeStackDepth)
+        newExc.setStackTrace(exc.getStackTrace)
+        throw newExc
+    }
   }
 
   def getTestOptions: TesterOptions = {

src/main/scala/chisel3/tester/TestEnvInterface.scala

@@ -0,0 +1,70 @@
+// See LICENSE for license details.
+
+package chisel3.tester
+
+import scala.collection.mutable
+
+class FailedExpectException(val message: String, val failedCodeStackDepth: Int) extends Exception(message)
+
+/** Interface into the testing environment, like ScalaTest
+  */
+trait TestEnvInterface {
+  protected val batchedFailures: mutable.ArrayBuffer[Exception] = new mutable.ArrayBuffer
+
+  def topFileName: Option[String]
+
+  /** Logs a tester failure at this point.
+    * Failures queued until the next checkpoint.
+    */
+  def testerFail(msg: String): Unit = {
+    batchedFailures += new FailedExpectException(msg, 4)
+  }
+
+  protected def getExpectDetailedTrace(trace: Seq[StackTraceElement], inFile: String): String = {
+    val fullTrace = Context().backend.getParentTraceElements ++ trace
+
+    // In the threading case, this needs to be overridden to trace through parent threads
+    val lineNumbers = fullTrace.collect {
+      case ste if ste.getFileName == inFile => ste.getLineNumber
+    }.mkString(", ")
+    if (lineNumbers.isEmpty) {
+      s" (no lines in $inFile)"
+    } else {
+      s" (lines in $inFile: $lineNumbers)"
+    }
+  }
+
+  /** Expect a specific value on a wire, calling testerFail if the expectation isn't met.
+    * Failures queued until the next checkpoint.
+    */
+  def testerExpect(expected: Any, actual: Any, signal: String, msg: Option[String]): Unit = {
+    if (expected != actual) {
+      val appendMsg = msg match {
+        case Some(_) => s": $msg"
+        case _ => ""
+      }
+
+      val trace = new Throwable
+      val expectStackDepth = trace.getStackTrace.indexWhere(ste =>
+        ste.getClassName == "chisel3.tester.package$testableData" && ste.getMethodName == "expect")
+      require(expectStackDepth != -1,
+        s"Failed to find expect in stack trace:\r\n${trace.getStackTrace.mkString("\r\n")}")
+
+      val trimmedTrace = trace.getStackTrace.drop(expectStackDepth + 2)
+      val detailedTrace = topFileName.map(getExpectDetailedTrace(trimmedTrace.toSeq, _)).getOrElse("")
+
+      val message = s"$signal=$actual did not equal expected=$expected$appendMsg$detailedTrace"
+      val stackIndex = expectStackDepth + 1
+      batchedFailures += new FailedExpectException(message, stackIndex)
+    }
+  }
+
+  /** If there are any failures, reports them and end the test now.
+    */
+  def checkpoint(): Unit = {
+    // TODO: report multiple exceptions simultaneously
+    for (failure <- batchedFailures) {
+      throw failure
+    }
+  }
+}