1 files changed, 24 insertions, 10 deletions
diff --git a/core/src/test/java/coffee/liz/lambda/format/ValueEmitterTest.java b/core/src/test/java/coffee/liz/lambda/format/ValueEmitterTest.java
index c1ab704..959f45d 100644
--- a/core/src/test/java/coffee/liz/lambda/format/ValueEmitterTest.java
+++ b/core/src/test/java/coffee/liz/lambda/format/ValueEmitterTest.java
@@ -12,7 +12,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 
 class ValueEmitterTest {
     @Test
-    void emitsFreeInBothSyntaxes() {
+    public void testEmitsFreeInBothSyntaxes() {
         final Value value = LambdaDriver.interpret(SourceCode.ofArrow("z"));
 
         final SourceCode arrow = ValueEmitter.emit(value, SourceCode.Syntax.ARROW);
@@ -23,7 +23,7 @@ class ValueEmitterTest {
     }
 
     @Test
-    void emitsApplicationInBothSyntaxes() {
+    public void testEmitsApplicationInBothSyntaxes() {
         final Value value = LambdaDriver.interpret(SourceCode.ofArrow("f(x)"));
 
         final SourceCode arrow = ValueEmitter.emit(value, SourceCode.Syntax.ARROW);
@@ -34,27 +34,41 @@ class ValueEmitterTest {
     }
 
     @Test
-    void emitsClosureWithCaptureMacros() {
+    public void testEmitsClosureWithCaptureMacros() {
         final Value value = LambdaDriver.interpret(SourceCode.ofArrow("(x -> y -> x)(z)"));
         final SourceCode emitted = ValueEmitter.emit(value, SourceCode.Syntax.ARROW);
         final String source = assertInstanceOf(SourceCode.Arrow.class, emitted).source();
 
-        assertTrue(source.contains("let _cap"));
-        assertTrue(source.contains("y -> _cap"));
+        assertEquals("""
+            let x = z;
+
+            y -> x""", source);
 
-        // Validate emitted program is parsable and evaluates.
         final Value roundTrip = LambdaDriver.interpret(emitted);
         assertInstanceOf(Value.Closure.class, roundTrip);
     }
 
     @Test
-    void emitsHygienicCapturesWhenNamesShadow() {
+    public void testEmitsHygienicCapturesWhenNamesShadow() {
         final Value value = LambdaDriver.interpret(SourceCode.ofArrow("(x -> y -> x)(y)"));
         final SourceCode emitted = ValueEmitter.emit(value, SourceCode.Syntax.ARROW);
         final String source = assertInstanceOf(SourceCode.Arrow.class, emitted).source();
 
-        assertTrue(source.contains("let _cap"));
-        assertTrue(source.contains("y -> _cap"));
-        assertFalse(source.contains("let y ="));
+        assertEquals("""
+            let x = y;
+
+            y -> x""", source);
+    }
+
+    @Test
+    public void testPrunesUnusedEnvironmentCaptures() {
+        final Value value = LambdaDriver.interpret(SourceCode.ofArrow("(x -> w -> y -> x)(z)(q)"));
+        final SourceCode emitted = ValueEmitter.emit(value, SourceCode.Syntax.ARROW);
+        final String source = assertInstanceOf(SourceCode.Arrow.class, emitted).source();
+
+        assertEquals("""
+            let x = z;
+
+            y -> x""", source);
     }
 }