1 files changed, 44 insertions, 0 deletions
diff --git a/src/test/scala/chiselTests/TesterDriverSpec.scala b/src/test/scala/chiselTests/TesterDriverSpec.scala
new file mode 100644
index 00000000..dfdd07cc
--- /dev/null
+++ b/src/test/scala/chiselTests/TesterDriverSpec.scala
@@ -0,0 +1,44 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import Chisel._
+import Chisel.testers.BasicTester
+
+/** Extend BasicTester with a simple circuit and finish method.  TesterDriver will call the
+  * finish method after the FinishTester's constructor has completed, which will alter the
+  * circuit after the constructor has finished.
+  */
+class FinishTester extends BasicTester {
+  val test_wire_width = 2
+  val test_wire_override_value = 3
+
+  val counter = Counter(1)
+
+  when(counter.inc()) {
+    stop()
+  }
+
+  val test_wire = Wire(UInt(1, width = test_wire_width))
+
+  // though we just set test_wire to 1, the assert below will pass because
+  // the finish will change it's value
+  assert(test_wire === UInt(test_wire_override_value))
+
+  /** In finish we use last connect semantics to alter the test_wire in the circuit
+    * with a new value
+    */
+  override def finish(): Unit = {
+    test_wire := UInt(test_wire_override_value)
+  }
+}
+
+class TesterDriverSpec extends ChiselFlatSpec {
+  "TesterDriver calls BasicTester's finish method which" should
+    "allow modifications of test circuit after the tester's constructor is done" in {
+    assertTesterPasses {
+      new FinishTester
+    }
+  }
+}
+