add tox and fix poetry

pyproject.toml

@@ -1,6 +1,6 @@
 [build-system]
-requires = ["poetry_core"]
-build-backend = "poetry.core.masonry.api"
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
 
 
 [tool.poetry]
@@ -21,9 +21,6 @@ classifiers = [
   "Topic :: Software Development :: Libraries :: Python Modules",
   "Topic :: System :: Systems Administration :: Authentication/Directory"
 ]
-packages = [
-  { include = "src/pyrad3"},
-]
 include = [
   "LICENSE-APACHE",
   "LICENSE-MIT",
@@ -34,6 +31,7 @@ include = [
 [tool.poetry.urls]
 repository = "https://github.com/pyradius/pyrad3"
 
+
 [tool.poetry.dependencies]
 python = "^3.7"
 
@@ -43,6 +41,8 @@ black = "^19.3.10b0"
 pytest = "^5.4"
 pytest-black = "^0.3.10"
 pytest-cov = "^2.10"
+pytest-flake8 = "^1.0"
+pytest-isort = "^1.1.0"
 pytest-mypy = "^0.6"
 pytest-pylint = "^0.17"
 
@@ -53,12 +53,27 @@ include = '\.py'
 
 
 [tool.isort]
-multi_line_output = 3
-include_trailing_comma = true
-use_parentheses = true
-line_length = 88
 combine_as_imports = true
+include_trailing_comma = true
+line_length = 88
+multi_line_output = 3
+use_parentheses = true
 
 
 [tool.pylint.messages_control]
 disable = "bad-continuation"
+
+
+[tool.tox]
+legacy_tox_ini = """
+[tox]
+envlist = py37,py38
+isolated_build = True
+[testenv]
+# whitelist_externals = poetry
+deps =
+  poetry
+commands =
+  poetry install -v
+  poetry run pytest --black --isort --pylint --pylint-jobs=4 --mypy --flake8 --cov=pyrad3
+"""