Break requirements down on per backend basis

.travis.yml

@@ -6,9 +6,7 @@ language: python
 python:
   - "3.7"
 install:
-   - pip install -e .
-   - pip install -r requirements.txt
-   - pip install -r requirements-optional.txt
+   - pip install -e .[all]
    - docker pull quen2404/openapi-diff
 script:
    - py.test --cov=optimade

optimade/filtertransformers/tests/test_django.py

@@ -1,6 +1,11 @@
 import json
-from optimade.filtertransformers.django import Lark2Django
-from unittest import TestCase
+try:
+    from optimade.filtertransformers.django import Lark2Django
+    DJANGO_NOT_IMPORTED = False
+except ImportError:
+    DJANGO_NOT_IMPORTED = True
+
+from unittest import TestCase, skipIf
 import os
 
 test_data = [
@@ -17,6 +22,7 @@
 ]
 
 
+@skipIf(DJANGO_NOT_IMPORTED, 'Django not found')
 class DjangoParserTest(TestCase):
     @classmethod
     def setUpClass(cls):

requirements.txt

@@ -1,7 +1,5 @@
 # To pin testing and deployments to specific versions
 fastapi[all]==0.28.0
 lark-parser==0.5.6
-mongogrant==0.2.2
-mongomock==3.16.0
+mongomock==3.16
 pymongo==3.8.0
-django==2.2.5

requirements/django_requirements.txt

@@ -0,0 +1 @@
+django==2.2.5

requirements/mongo_requirements.txt

@@ -0,0 +1 @@
+mongogrant==0.2.2

setup.py

@@ -1,9 +1,31 @@
 import os
+import glob
 
 from setuptools import setup, find_packages
 
 module_dir = os.path.dirname(os.path.abspath(__file__))
 
+with open("requirements.txt") as f:
+    requirements = [
+        line.strip()
+        for line in f.readlines()
+        if line and not line.strip().startswith("#")
+    ]
+
+extra_requirements = {}
+for fname in glob.glob("requirements/*_requirements.txt"):
+    req = os.path.basename(fname).split("_")[0]
+    with open(fname, "r") as f:
+        extra_requirements[req] = [
+            line.strip()
+            for line in f.readlines()
+            if line and not line.strip().startswith("#")
+        ]
+
+extra_requirements["all"] = [
+    req for key in extra_requirements for req in extra_requirements[key]
+]
+
 setup(
     name="optimade",
     version="0.2.0",
@@ -16,14 +38,8 @@
     description="Tools for implementing and consuming OPTiMaDe APIs.",
     long_description=open(os.path.join(module_dir, "README.md")).read(),
     long_description_content_type="text/markdown",
-    install_requires=[
-        "pymongo>=3.8",
-        "lark-parser>=0.5.6",
-        "mongogrant",
-        "mongomock>=3.16",
-        "fastapi[all]",
-    ],
-    extras_require={"dev": ["black", "invoke", "pre-commit", "twine"]},
+    install_requires=requirements,
+    extras_require=extra_requirements,
     tests_require=["pytest>=3.6", "openapi-spec-validator", "jsondiff"],
     classifiers=[
         "Development Status :: 3 - Alpha",