Reject negative shift amounts; add tests (#730)

Closes #729

1 files changed, 3 insertions, 0 deletions

diff --git a/src/test/scala/chiselTests/FixedPointSpec.scala b/src/test/scala/chiselTests/FixedPointSpec.scala
index 8caa7f1e..ff4b42a0 100644
--- a/src/test/scala/chiselTests/FixedPointSpec.scala
+++ b/src/test/scala/chiselTests/FixedPointSpec.scala
@@ -126,4 +126,7 @@ class FixedPointSpec extends ChiselPropSpec {
   property("should mux different widths and binary points") {
     assertTesterPasses { new FixedPointMuxTester }
   }
+  property("Negative shift amounts are invalid") {
+    a [ChiselException] should be thrownBy { elaborate(new NegativeShift(FixedPoint(1.W, 0.BP))) }
+  }
 }