Looking at vue-cli repository I see two different ways of scaffolding vue projects.
The v3 (beta) version, installed as
npm install -g @vue/cli, creates projects using the following command:vue create my-project
While the version 2.9.x, available at master branch, is installed as
npm install -g vue-cli and it allows projects scaffolding with the following:vue init <template-name> <project-name>
for example:
vue init webpack my-project
So, in your scenario, for v3 version you should use:
vue create test-app.
Here you can find further information.
