JS Interop Facade generation polish.

test/declaration_test.ts

 /// <reference path="../typings/mocha/mocha.d.ts"/>
 import {expectErroneousCode, expectTranslate} from './test_support';
 
 describe('variables', () => {
   it('should print variable declaration with initializer', () => {
     expectTranslate('var a:number = 1;').to.equal(`@JS()
 external num get a;
 @JS()
 external set a(num v);`);
   });
@@ skipping 374 matching lines @@
     expectTranslate('interface X { x: string; y; }').to.equal(`@anonymous
 @JS()
 abstract class X {
   external String get x;
   external set x(String v);
   external get y;
   external set y(v);
   external factory X({String x, y});
 }`);
   });
+
+  it('supports interfaces with constructors', () => {
+    expectTranslate(`
+interface XStatic {
+  new (a: string, b): X;
+  foo();
+}
+
+declare var X: XStatic;
+`).to.equal(`@JS("X")
+abstract class XStatic {
+  external factory XStatic(String a, b);
+  external foo();
+}
+
+@JS()
+external XStatic get X;
+@JS()
+external set X(XStatic v);`);
+
+    expectTranslate(`
+interface XStatic {
+  new (a: string, b): XStatic;
+  foo();
+}
+
+declare module Foo {
+  declare var X: XStatic;
+}
+`).to.equal(`@JS("Foo.X")
+abstract class XStatic {
+  external factory XStatic(String a, b);
+  external foo();
+}
+
+// Module Foo
+@JS("Foo.X")
+external XStatic get X;
+@JS("Foo.X")
+external set X(XStatic v);
+// End module Foo`);
+
+    // Case where we cannot find a variable matching the interface so it is unsafe to give the
+    // interface a constructor.
+    expectTranslate(`
+interface XStatic {
+  new (a: string|bool, b): XStatic;
+  foo();
+}`).to.equal(`@anonymous
+@JS()
+abstract class XStatic {
+  // Constructors on anonymous interfaces are not yet supported.
+  /*external factory XStatic(String|bool a, b);*/
+  external foo();
+}`);
+  });
 });
 
 describe('single call signature interfaces', () => {
   it('should support declaration', () => {
     expectTranslate('interface F { (n: number): boolean; }').to.equal('typedef bool F(num n);');
   });
   it('should support generics', () => {
     expectTranslate('interface F<A, B> { (a: A): B; }').to.equal('typedef B F<A, B>(A a);');
   });
 });
@@ skipping 19 matching lines @@
   external static num get Blue;
 }`);
   });
   it('should ingore switch', () => {
     expectTranslate('switch(c) { case Color.Red: break; default: break; }').to.equal('');
   });
   it('does not support const enum', () => {
     expectErroneousCode('const enum Color { Red }').to.throw('const enums are not supported');
   });
 });