I have copied the ansible "copy" module to the project but the copied module does not work - ansible

Question

I have developed the ansible modules.
I have copied the ansible's copy module's source code copy.py to the project's root directory as c_copy.py("c_copy" module), and execute the task used the "c_copy" module. As a result, I can't understand but the task have failed although the task used the "copy" module have suceeeded.
It seems that the "c_copy" module can't find files in the role's files directory.
So, please tell me why "c_copy" module does not work at well.
To ask your help, I have created the github repository.
https://github.com/suzuki-shunsuke/ansible-module-test-example
You can check my source code and reproduce my problem.
Requirements to reproduce
Python 2.7.12(pyenv)
pip
Vagrant(My Vagrant version is 1.8.6)
Setup
$ git clone https://github.com/suzuki-shunsuke/ansible-module-test-example
$ cd ansible-module-test-example
$ pyenv install 2.7.12
$ pip install --upgrade pip
$ pip install --upgrade virtualenv
$ virtualenv env
$ source env/bin/activate
$ cp env/lib/python2.7/site-packages/ansible/modules/core/files/copy.py c_copy.py
Test
$ vagrant up --provision-with=ansible
ansible.cfg
[defaults]
library = .
tasks/main.yml
- name: run the copy module
copy:
src: test.txt
dest: /tmp/test.txt
- name: run the clone of the copy module
c_copy:
src: test.txt
dest: /tmp/c_test.txt
Result
TASK [copy : run the copy module] **********************************************
changed: [default]
TASK [copy : run the clone of the copy module] *********************************
fatal: [default]: FAILED! => {"changed": false, "failed": true, "msg": "Source test.txt not found"}

Answer 1

Some modules are wrapped with action plugins.
Here is one for copy module.
So when you call copy, Ansible executes action plugin copy, which in turn calls copy module.
When there is no action plugin, module with the same name called directly.
If you look into copy action plugin code, you'll notice a bunch of file handling stuff, that your c_copy module omits.
Try to duplicate action plugin code and test your setup again.