Use src layout to make sure we test the right thing

see https://docs.pytest.org/en/latest/goodpractices.html
and https://hynek.me/articles/testing-packaging/

Also, make tox a Poetry dev dependency again.
tox can in fact be used from inside the virtual env.

Author: Cito

.bumpversion.cfg

@@ -3,7 +3,7 @@ current_version = 1.1.0b0
 commit = False
 tag = False
 
-[bumpversion:file:graphql/version.py]
+[bumpversion:file:src/graphql/version.py]
 search = __version__ = "{current_version}"
 replace = __version__ = "{new_version}"
 

.coveragerc

@@ -1,6 +1,6 @@
 [run]
 branch = True
-source = graphql
+source = src
 
 [report]
 exclude_lines =

.travis.yml

@@ -23,7 +23,7 @@ install:
   - poetry install
 
 script:
-   - tox -e $TOXENV -- --cov-report term-missing --cov=graphql
+   - tox -e $TOXENV -- --cov-report term-missing --cov=src
 
 after_success:
    - codecov

MANIFEST.in

@@ -16,7 +16,7 @@ include tox.ini
 include poetry.lock
 include pyproject.toml
 
-graft graphql
+graft src/graphql
 graft tests
 recursive-include docs *.rst conf.py Makefile make.bat *.jpg *.png *.gif
 prune docs/_build

poetry.lock

@@ -22,7 +22,7 @@ classifiers = [
     "Programming Language :: Python :: 3.7"
 ]
 packages = [
-    { include = "graphql" },
+    { include = "graphql", from = "src" },
 ]
 
 [tool.poetry.dependencies]
@@ -42,6 +42,7 @@ sphinx = "^2.1"
 sphinx_rtd_theme = ">=0.4"
 check-manifest = ">=0.39"
 bump2version = ">=0.5"
+tox = "^3.13"
 
 [tool.black]
 target-version = ['py36', 'py37', 'py38']

pyproject.toml

@@ -1,7 +1,7 @@
 from re import search
 from setuptools import setup, find_packages
 
-with open("graphql/version.py") as version_file:
+with open("src/graphql/version.py") as version_file:
     version = search('version = "(.*)"', version_file.read()).group(1)
 
 with open("README.md") as readme_file:
@@ -29,8 +29,9 @@
         "Programming Language :: Python :: 3.7",
     ],
     install_requires=[],
-    python_requires=">=3.6",
-    packages=find_packages(include=["graphql"]),
+    python_requires=">=3.6,<4",
+    packages=find_packages("src"),
+    package_dir={"": "src"},
     # PEP-561: https://www.python.org/dev/peps/pep-0561/
     package_data={"graphql": ["py.typed"]},
     include_package_data=True,