[Interop][Test] Add test for CEnumVar.value property

backend.native/tests/build.gradle

@@ -3477,6 +3477,10 @@ createInterop("cunion") {
     it.defFile 'interop/basics/cunion.def'
 }
 
+createInterop("cenums") {
+    it.defFile 'interop/basics/cenums.def'
+}
+
 createInterop("carrayPointers") {
     it.defFile 'interop/basics/carrayPointers.def'
 }
@@ -3736,6 +3740,12 @@ interopTest("interop_union") {
     source = "interop/basics/union.kt"
 }
 
+interopTest("interop_enums") {
+    disabled = (project.testTarget == 'wasm32') // No interop for wasm yet.
+    interop = 'cenums'
+    source = "interop/basics/enums.kt"
+}
+
 interopTest("interop_array_pointers") {
     disabled = (project.testTarget == 'wasm32') // No interop for wasm yet.
     interop = 'carrayPointers'

backend.native/tests/interop/basics/cenums.def

@@ -0,0 +1,4 @@
+---
+enum E {
+    A, B, C
+};

backend.native/tests/interop/basics/enums.kt

@@ -0,0 +1,15 @@
+import cenums.*
+import kotlinx.cinterop.*
+import kotlin.test.*
+
+fun main() {
+    memScoped {
+        val e = alloc<E.Var>()
+        e.value = E.C
+        assertEquals(E.C, e.value)
+
+        assertFailsWith<NotImplementedError> {
+            e.value = TODO()
+        }
+    }
+}