1 files changed, 71 insertions, 0 deletions
diff --git a/src/test/scala/chiselTests/ExtModule.scala b/src/test/scala/chiselTests/ExtModule.scala
new file mode 100644
index 00000000..f8927b9f
--- /dev/null
+++ b/src/test/scala/chiselTests/ExtModule.scala
@@ -0,0 +1,71 @@
+// See LICENSE for license details.
+
+package chiselTests
+
+import java.io.File
+
+import org.scalatest._
+import chisel3._
+import chisel3.experimental._
+import chisel3.testers.BasicTester
+import chisel3.util._
+
+// Avoid collisions with regular BlackBox tests by putting ExtModule blackboxes
+// in their own scope.
+package ExtModule {
+  class BlackBoxInverter extends ExtModule {
+    val in = IO(Input(Bool()))
+    val out = IO(Output(Bool()))
+  }
+
+  class BlackBoxPassthrough extends ExtModule {
+    val in = IO(Input(Bool()))
+    val out = IO(Output(Bool()))
+  }
+}
+
+class ExtModuleTester extends BasicTester {
+  val blackBoxPos = Module(new ExtModule.BlackBoxInverter)
+  val blackBoxNeg = Module(new ExtModule.BlackBoxInverter)
+
+  blackBoxPos.in := 1.U
+  blackBoxNeg.in := 0.U
+
+  assert(blackBoxNeg.out === 1.U)
+  assert(blackBoxPos.out === 0.U)
+  stop()
+}
+
+/** Instantiate multiple BlackBoxes with similar interfaces but different
+  * functionality. Used to detect failures in BlackBox naming and module
+  * deduplication.
+  */
+
+class MultiExtModuleTester extends BasicTester {
+  val blackBoxInvPos = Module(new ExtModule.BlackBoxInverter)
+  val blackBoxInvNeg = Module(new ExtModule.BlackBoxInverter)
+  val blackBoxPassPos = Module(new ExtModule.BlackBoxPassthrough)
+  val blackBoxPassNeg = Module(new ExtModule.BlackBoxPassthrough)
+
+  blackBoxInvPos.in := 1.U
+  blackBoxInvNeg.in := 0.U
+  blackBoxPassPos.in := 1.U
+  blackBoxPassNeg.in := 0.U
+
+  assert(blackBoxInvNeg.out === 1.U)
+  assert(blackBoxInvPos.out === 0.U)
+  assert(blackBoxPassNeg.out === 0.U)
+  assert(blackBoxPassPos.out === 1.U)
+  stop()
+}
+
+class ExtModuleSpec extends ChiselFlatSpec {
+  "A ExtModule inverter" should "work" in {
+    assertTesterPasses({ new ExtModuleTester },
+        Seq("/BlackBoxTest.v"))
+  }
+  "Multiple ExtModules" should "work" in {
+    assertTesterPasses({ new MultiExtModuleTester },
+        Seq("/BlackBoxTest.v"))
+  }
+}