chore(dept): move test data to flag demo

README.md

@@ -36,18 +36,30 @@ Below we provide instructions for `pip` installation.
 
 To build the package from source, run:
 
+```bash
+pip install 'ermsfkit @ git+https://github.com/pablo-arantes/ermsfkit.git'
+
+or
+
+git clone https://github.com/pablo-arantes/ermsfkit.git
+pip install .
 ```
-pip install git+https://github.com/pablo-arantes/ermsfkit.git
+
+To install the package with demo data, run:
+
+```bash
+pip install 'ermsfkit[demo] @ git+https://github.com/pablo-arantes/ermsfkit.git'
 
 or
 
 git clone https://github.com/pablo-arantes/ermsfkit.git
-pip install ermsfkit/
+pip install '.[demo]'
 ```
+
 #### Usage
 Below we provide an example of use:
 
-```
+```python
 from eRMSF import ermsfkit
 import MDAnalysis as mda
 import matplotlib.pyplot as plt

eRMSF/tests/test_install_extra_tag.py

@@ -0,0 +1,25 @@
+import sys
+import subprocess
+import os
+
+import pytest
+
+
+
+@pytest.mark.parametrize(
+        'command, has_test_data_dep',
+        [
+            ([sys.executable, '-m','pip', 'install', '.'], False),
+            ([sys.executable, '-m','pip', 'install', '.[demo]'], True),
+        ]
+)
+def test_install_cmd_pip_local(command: list, has_test_data_dep: bool):
+    command.append('--dry-run')
+    ret=subprocess.check_output(command)
+
+    # raise RuntimeError(ret)
+
+    ret_has_test_data_dep = 'MDAnalysisTests' in ret.decode()
+    assert ret_has_test_data_dep == has_test_data_dep
+
+

pyproject.toml

@@ -19,7 +19,7 @@ readme = "README.md"
 requires-python = ">=3.9"
 dependencies = [
     "MDAnalysis>=2.0.0",
-    "MDAnalysisTests>=2.7.0",
+
 ]
 keywords = [
     "molecular simulations",
@@ -29,6 +29,11 @@ dynamic = [
 ]
 
 [project.optional-dependencies]
+
+demo = [
+    "MDAnalysisTests>=2.7.0",
+]
+
 test = [
     "pytest>=6.0",
     "pytest-xdist>=2.5",