Add tests for variable declarations

test/mjsunit/harmony/typesystem/string-literal-types.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --harmony-types
 
-function CheckValid(type) {
-  // print("V:", type);
-  assertDoesNotThrow("'use types'; var x: " + type + ";");
-}
 
-function CheckInvalid(type) {
-  // print("I:", type);
-  assertThrows("'use types'; var x: " + type + ";", SyntaxError);
-}
+load("test/mjsunit/harmony/typesystem/testgen.js");
+
 
 (function TestStringLiteralTypes() {
   // These are not really valid here.
   // They should only be valid in function/constructor signatures.
-  CheckValid("(cmd: 'add', x: number, y: number) => number");
-  CheckValid('(cmd: "sum", a: number[]) => number');
-  CheckValid("(x: number, cmd: 'one', ...rest) => any");
-  CheckValid("(x: string, y: number, cmd: 'two', ...rest) => any");
-  CheckValid("(x: number, cmd?: 'two', ...rest) => string");
+  CheckValidType("(cmd: 'add', x: number, y: number) => number");
+  CheckValidType('(cmd: "sum", a: number[]) => number');
+  CheckValidType("(x: number, cmd: 'one', ...rest) => any");
+  CheckValidType("(x: string, y: number, cmd: 'two', ...rest) => any");
+  CheckValidType("(x: number, cmd?: 'two', ...rest) => string");
   // String literal types where they shouldn't be.
-  CheckInvalid("'foo'");
-  CheckInvalid("('foo')");
-  CheckInvalid("'foo'[]");
-  CheckInvalid("('foo')[]");
-  CheckInvalid("('foo'[])");
-  CheckInvalid("(('foo')[])");
-  CheckInvalid("'foo' | 'bar'");
-  CheckInvalid("('foo') => any");
+  CheckInvalidType("'foo'");
+  CheckInvalidType("('foo')");
+  CheckInvalidType("'foo'[]");
+  CheckInvalidType("('foo')[]");
+  CheckInvalidType("('foo'[])");
+  CheckInvalidType("(('foo')[])");
+  CheckInvalidType("'foo' | 'bar'");
+  CheckInvalidType("('foo') => any");
 })();