1 files changed, 31 insertions, 0 deletions
diff --git a/src/test/java/org/shedlang/compiler/stackir/StackCompilerEffectDefinitionTests.java b/src/test/java/org/shedlang/compiler/stackir/StackCompilerEffectDefinitionTests.java
new file mode 100644
index 00000000..e167816c
--- /dev/null
+++ b/src/test/java/org/shedlang/compiler/stackir/StackCompilerEffectDefinitionTests.java
@@ -0,0 +1,31 @@
+package org.shedlang.compiler.stackir;
+
+import org.junit.jupiter.api.Test;
+import org.shedlang.compiler.ast.typed.Typed;
+import org.shedlang.compiler.stackir.instructions.DefineEffectInstruction;
+import org.shedlang.compiler.types.Effects;
+import org.shedlang.compiler.types.NamespaceName;
+
+import static org.shedlang.compiler.stackir.instructions.InstructionMatchers.isLocalStoreInstruction;
+import static org.zwobble.precisely.AssertThat.assertThat;
+import static org.zwobble.precisely.Matchers.*;
+
+public class StackCompilerEffectDefinitionTests {
+    @Test
+    public void effectDefinitionIsCompiledToDefineEffectInstruction() {
+        var effect = Effects.userDefined(NamespaceName.of("Example", "Project"), "State");
+        var node = Typed.effectDefinition(effect);
+        var context = StackCompiler.Context.EMPTY
+            .addShedVariable("State");
+
+        var result = StackCompiler.compileNamespaceStatement(node, context);
+
+        assertThat(result.instructions(), isSequence(
+            instanceOf(
+                DefineEffectInstruction.class,
+                has("effect", x -> x.effect(), equalTo(effect))
+            ),
+            isLocalStoreInstruction("State__0")
+        ));
+    }
+}