2 files changed, 13 insertions, 0 deletions
diff --git a/src/test/java/org/shedlang/compiler/stackir/InstructionSerializerTests.java b/src/test/java/org/shedlang/compiler/stackir/InstructionSerializerTests.java
index bfbec2a6..d6f4b830 100644
--- a/src/test/java/org/shedlang/compiler/stackir/InstructionSerializerTests.java
+++ b/src/test/java/org/shedlang/compiler/stackir/InstructionSerializerTests.java
@@ -64,6 +64,15 @@ public class InstructionSerializerTests {
     }
 
     @Test
+    public void canSerializeDuplicate() {
+        var instruction = Instructions.duplicate();
+
+        var string = serialize(instruction);
+
+        assertThat(string, equalTo("(duplicate)"));
+    }
+
+    @Test
     public void canSerializeFieldLoad() {
         var instruction = Instructions.fieldLoad(
             new NamespaceName(List.of("Example", "Lib")),
diff --git a/src/test/java/org/shedlang/compiler/stackir/instructions/Instructions.java b/src/test/java/org/shedlang/compiler/stackir/instructions/Instructions.java
index dbef836e..126ad1fa 100644
--- a/src/test/java/org/shedlang/compiler/stackir/instructions/Instructions.java
+++ b/src/test/java/org/shedlang/compiler/stackir/instructions/Instructions.java
@@ -18,6 +18,10 @@ public class Instructions {
         return new DiscardInstruction(Sources.NULL);
     }
 
+    public static Instruction duplicate() {
+        return new DuplicateInstruction(Sources.NULL);
+    }
+
     public static Instruction fieldLoad(NamespaceName namespaceName, String fieldName) {
         return new FieldLoadInstruction(namespaceName, fieldName, Sources.NULL);
     }