1 files changed, 60 insertions, 0 deletions
diff --git a/src/test/scala/chiselTests/ChiselTestUtilitiesSpec.scala b/src/test/scala/chiselTests/ChiselTestUtilitiesSpec.scala
new file mode 100644
index 00000000..6d3d526c
--- /dev/null
+++ b/src/test/scala/chiselTests/ChiselTestUtilitiesSpec.scala
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: Apache-2.0
+
+package chiselTests
+
+import chisel3._
+import org.scalatest.exceptions.TestFailedException
+
+class ChiselTestUtilitiesSpec extends ChiselFlatSpec {
+  // Who tests the testers?
+  "assertKnownWidth" should "error when the expected width is wrong" in {
+    val caught = intercept[ChiselException] {
+      assertKnownWidth(7) {
+        Wire(UInt(8.W))
+      }
+    }
+    assert(caught.getCause.isInstanceOf[TestFailedException])
+  }
+
+  it should "error when the width is unknown" in {
+    a [ChiselException] shouldBe thrownBy {
+      assertKnownWidth(7) {
+        Wire(UInt())
+      }
+    }
+  }
+
+  it should "work if the width is correct" in {
+    assertKnownWidth(8) {
+      Wire(UInt(8.W))
+    }
+  }
+
+  "assertInferredWidth" should "error if the width is known" in {
+    val caught = intercept[ChiselException] {
+      assertInferredWidth(8) {
+        Wire(UInt(8.W))
+      }
+    }
+    assert(caught.getCause.isInstanceOf[TestFailedException])
+  }
+
+  it should "error if the expected width is wrong" in {
+    a [TestFailedException] shouldBe thrownBy {
+      assertInferredWidth(8) {
+        val w = Wire(UInt())
+        w := 2.U(2.W)
+        w
+      }
+    }
+  }
+
+  it should "pass if the width is correct" in {
+    assertInferredWidth(4) {
+      val w = Wire(UInt())
+      w := 2.U(4.W)
+      w
+    }
+  }
+}
+