fix: install NG CLI globally

NativeScript/nativescript-schematics#214 require global installation of NG CLI.

Since we do not rely heavily on NG CLI I suggest insalling it globally.
If we encounter troubles we may try local install and custom NPM prefix.

Author: dtopuzov

core/utils/npm.py

@@ -14,7 +14,7 @@ class Npm(object):
     @staticmethod
     def run_npm_command(cmd, folder=Settings.TEST_RUN_HOME, verify=True):
         command = 'npm {0}'.format(cmd).strip()
-        Log.info(command + " (at " + folder + ").")
+        Log.info(command + " (at " + str(folder) + ").")
         result = run(cmd=command, cwd=folder, wait=True, timeout=300)
         if verify:
             assert result.exit_code == 0, '" + command + " exited with non zero exit code!: \n' + result.output
@@ -48,7 +48,7 @@ def pack(folder, output_file):
         File.delete(src_file)
 
     @staticmethod
-    def install(package='', option='', folder=None):
+    def install(package='', option='', folder=Settings.TEST_RUN_HOME):
         if package is None:
             raise NameError('Package can not be None.')
         command = 'i {0} {1}'.format(package, option)
@@ -57,7 +57,7 @@ def install(package='', option='', folder=None):
         return output
 
     @staticmethod
-    def uninstall(package, option='', folder=None):
+    def uninstall(package, option='', folder=Settings.TEST_RUN_HOME):
         if package is None or package == '':
             raise NameError('Package can not be None.')
         return Npm.run_npm_command('un {0} {1}'.format(package, option), folder=folder)

run_common.py

@@ -105,14 +105,10 @@ def __install_ns_cli():
 
 def __install_ng_cli():
     """
-    Install Angular CLI locally.
+    Install Angular CLI globally.
     """
-    Npm.install(package=Settings.Packages.NG_CLI, folder=Settings.TEST_RUN_HOME)
-
-    # Verify executable exists after install
-    path = os.path.join(Settings.TEST_RUN_HOME, 'node_modules', '.bin', 'ng')
-    assert File.exists(path), 'Angular CLI executable not found at ' + path
-    Settings.Executables.NG = path
+    Npm.uninstall(package='@angular/cli', option='-g')
+    Npm.install(package=Settings.Packages.NG_CLI, option='-g')
 
 
 def __install_schematics():