adding ts compilation test and minor gulpfile fix

.travis.yml

@@ -7,3 +7,7 @@ node_js:
 matrix:
   allow_failures:
     - node_js: "4"
+
+before_script:
+  - npm i -g typescript
+  - tsc

gulpfile.js

@@ -528,21 +528,17 @@ gulp.task('default', function () {
 
 //This task is used to generate libraries based on the mappings specified above.
 gulp.task('codegen', function (cb) {
-  if (true) {
-    if (project === undefined) {
-      let arr = Object.keys(mappings);
-      for (let i = 0; i < arr.length; i++) {
-        codegen(arr[i], i);
-      }
-    } else {
-      if (mappings[project] === undefined) {
-        console.error('Invalid project name "' + project + '"!');
-        process.exit(1);
-      }
-      codegen(project, null);
+  if (project === undefined) {
+    let arr = Object.keys(mappings);
+    for (let i = 0; i < arr.length; i++) {
+      codegen(arr[i], i);
     }
   } else {
-    process.exit(1);
+    if (mappings[project] === undefined) {
+      console.error('Invalid project name "' + project + '"!');
+      process.exit(1);
+    }
+    codegen(project, null);
   }
 });
 

test/tsTest.js

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ * Licensed under the MIT License. See License.txt in the project root for
+ * license information.
+ */
+
+const path = require('path');
+const glob = require('glob');
+const execSync = require('child_process').execSync;
+
+let packagePaths = glob.sync(path.join(__dirname, '../lib/services', '/**/lib/*.d.ts'), 
+{ ignore: '**/node_modules/**/*.d.ts' });
+
+describe('tsc compilation:', function () {
+
+  packagePaths.forEach(function (path) {
+    it(`${path} should succeed.`, function (done) {
+      let cmd = `tsc ${path}`;
+      let result;
+      try {
+        result = execSync(cmd, { encoding: 'utf8' });
+        done();
+      } catch (err) {
+        let output = '';
+        if (err.stdout) output += err.stdout;
+        if (err.stderr) output += err.stderr;
+        done(output);
+      }
+    });
+  });
+});