Add test for cfg attributes

tests/wasm/attributes.js

@@ -0,0 +1,9 @@
+const wasm = require("wasm-bindgen-test.js");
+const assert = require("assert");
+
+exports.js_works = () => {
+  assert.strictEqual(wasm.valid_export(), true);
+  assert.strictEqual(wasm.invalid_export, undefined);
+  assert.strictEqual(wasm.valid_attr_export(), true);
+  assert.strictEqual(wasm.invalid_attr_export, undefined);
+};

tests/wasm/attributes.rs

@@ -0,0 +1,36 @@
+use wasm_bindgen::prelude::*;
+use wasm_bindgen_test::*;
+
+#[wasm_bindgen(module = "tests/wasm/attributes.js")]
+extern "C" {
+    fn js_works();
+}
+
+#[wasm_bindgen_test]
+fn works() {
+    js_works();
+}
+
+#[wasm_bindgen]
+#[cfg(target_arch = "wasm32")]
+pub fn valid_export() -> bool {
+    true
+}
+
+#[wasm_bindgen]
+#[cfg(not(target_arch = "wasm32"))]
+pub fn invalid_export() -> bool {
+    false
+}
+
+#[wasm_bindgen]
+#[cfg_attr(target_arch = "wasm32", no_mangle)]
+pub fn valid_attr_export() -> bool {
+    true
+}
+
+#[wasm_bindgen]
+#[cfg_attr(not(target_arch = "wasm32"), no_mangle)]
+pub fn invalid_attr_export() -> bool {
+    false
+}

tests/wasm/main.rs

@@ -16,6 +16,7 @@ use wasm_bindgen::prelude::*;
 
 pub mod api;
 pub mod arg_names;
+pub mod attributes;
 pub mod bigint;
 pub mod char;
 pub mod classes;