coverage: increase coverage of js_codegen

test/codegen/expect/map_keys.js

Index: test/codegen/expect/map_keys.js
diff --git a/test/codegen/expect/map_keys.js b/test/codegen/expect/map_keys.js
new file mode 100644
index 0000000000000000000000000000000000000000..6dc6957274799305808e1363cb7e75bec6fd6378
--- /dev/null
+++ b/test/codegen/expect/map_keys.js
@@ -0,0 +1,16 @@
+var map_keys;
+(function(exports) {
+  'use strict';
+  // Function main: () → dynamic
+  function main() {
+    core.print(dart.map({'1': 2, '3': 4, '5': 6}));
+    core.print(dart.map([1, 2, 3, 4, 5, 6]));
+    core.print(dart.map({'1': 2, [`${dart.notNull(new math.Random().nextInt(2)) + 2}`]: 4, '5': 6}));
+    let x = '3';
+    core.print(dart.map(['1', 2, x, 4, '5', 6]));
+    core.print(dart.map(['1', 2, null, 4, '5', 6]));
+  }
+  // Exports:
+  exports.main = main;
+})(map_keys || (map_keys = {}));
+//# sourceMappingURL=map_keys.js.map