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diff --git a/src/test/scala/firrtlTests/CompilerUtilsSpec.scala b/src/test/scala/firrtlTests/CompilerUtilsSpec.scala
new file mode 100644
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+++ b/src/test/scala/firrtlTests/CompilerUtilsSpec.scala
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+// See LICENSE for license details.
+
+package firrtlTests
+
+import firrtl._
+import firrtl.CompilerUtils.mergeTransforms
+
+class CompilerUtilsSpec extends FirrtlFlatSpec {
+
+  def genTransform(_inputForm: CircuitForm, _outputForm: CircuitForm) = new Transform {
+    def inputForm = _inputForm
+    def outputForm = _outputForm
+    def execute(state: CircuitState): CircuitState = state
+  }
+
+  // Core lowering transforms
+  val chirrtlToHigh = genTransform(ChirrtlForm, HighForm)
+  val highToMid = genTransform(HighForm, MidForm)
+  val midToLow = genTransform(MidForm, LowForm)
+  val chirrtlToLowList = List(chirrtlToHigh, highToMid, midToLow)
+
+  // Custom transforms
+  val chirrtlToChirrtl = genTransform(ChirrtlForm, ChirrtlForm)
+  val highToHigh = genTransform(HighForm, HighForm)
+  val midToMid = genTransform(MidForm, MidForm)
+  val lowToLow = genTransform(LowForm, LowForm)
+
+  val lowToHigh = genTransform(LowForm, HighForm)
+
+  val lowToLowTwo = genTransform(LowForm, LowForm)
+
+  behavior of "mergeTransforms"
+
+  it should "do nothing if there are no custom transforms" in {
+    mergeTransforms(chirrtlToLowList, List.empty) should be (chirrtlToLowList)
+  }
+
+  it should "insert transforms at the correct place" in {
+    mergeTransforms(chirrtlToLowList, List(chirrtlToChirrtl)) should be
+      (chirrtlToChirrtl +: chirrtlToLowList)
+    mergeTransforms(chirrtlToLowList, List(highToHigh)) should be
+      (List(chirrtlToHigh, highToHigh, highToMid, midToLow))
+    mergeTransforms(chirrtlToLowList, List(midToMid)) should be
+      (List(chirrtlToHigh, highToMid, midToMid, midToLow))
+    mergeTransforms(chirrtlToLowList, List(lowToLow)) should be
+      (chirrtlToLowList :+ lowToLow)
+  }
+
+  it should "insert transforms at the last legal location" in {
+    lowToLow should not be (lowToLowTwo) // sanity check
+    mergeTransforms(chirrtlToLowList :+ lowToLow, List(lowToLowTwo)).last should be (lowToLowTwo)
+  }
+
+  it should "insert multiple transforms correctly" in {
+    mergeTransforms(chirrtlToLowList, List(highToHigh, lowToLow)) should be
+      (List(chirrtlToHigh, highToHigh, highToMid, midToLow, lowToLow))
+  }
+
+  it should "handle transforms that raise the form" in {
+    mergeTransforms(chirrtlToLowList, List(lowToHigh)) match {
+      case chirrtlToHigh :: highToMid :: midToLow :: lowToHigh :: remainder =>
+        // Remainder will be the actual Firrtl lowering transforms
+        remainder.head.inputForm should be (HighForm)
+        remainder.last.outputForm should be (LowForm)
+      case _ => fail()
+    }
+  }
+
+  // Order is not always maintained, see note on function Scaladoc
+  it should "maintain order of custom tranforms" in {
+    mergeTransforms(chirrtlToLowList, List(lowToLow, lowToLowTwo)) should be
+      (chirrtlToLowList ++ List(lowToLow, lowToLowTwo))
+  }
+
+}
+