Attempt to build python 3.7.0 on OpenSuse Leap 15

[snippsat]

Now, just to be sure, when I create a new project, what command should i use to set up the virtual environment?

I see your note:

It's up to you,i use venv sometime because it work the same Windows/Linux/Mac as it's a build in part of Python.

pipenv for better control over dependencies and ease of use.
Like install movipy,all is done with one line and you get a nice dependencies graph.

# Make virtual environment and install all in one line
pipenv install moviepy 

λ pipenv graph
moviepy==0.2.3.5
  - decorator [required: >=4.0.2,<5.0, installed: 4.3.0]
  - imageio [required: >=2.1.2,<3.0, installed: 2.3.0]
    - numpy [required: Any, installed: 1.14.5]
    - pillow [required: Any, installed: 5.2.0]
  - numpy [required: Any, installed: 1.14.5]
  - tqdm [required: >=4.11.2,<5.0, installed: 4.23.4]

moviepy need imageio and imageio need numpy and pillow ect...