Replaced Pipenv with Poetry

Author: fbertola

.flake8

@@ -0,0 +1,7 @@
+[flake8]
+select = B,B9,BLK,C,E,F,I,S,W
+ignore = E203,E501,W503,E731,F405,F403,F401
+max-line-length = 128
+per-file-ignores = tests/*:S101
+import-order-style = google
+application-import-names = src,tests

noxfile.py

@@ -0,0 +1,64 @@
+import tempfile
+
+import nox
+
+locations = "demo", "natrix", "tests", "noxfile.py"
+
+
+def install_with_constraints(session, *args, **kwargs):
+    with tempfile.NamedTemporaryFile() as requirements:
+        session.run(
+            "poetry",
+            "export",
+            "--dev",
+            "--format=requirements.txt",
+            "--without-hashes",
+            f"--output={requirements.name}",
+            external=True,
+        )
+        session.install(f"--constraint={requirements.name}", *args, **kwargs)
+
+
+@nox.session(python="3.7")
+def black(session):
+    args = session.posargs or locations
+    install_with_constraints(session, "black")
+    session.run("black", *args)
+
+
+@nox.session(python="3.7")
+def lint(session):
+    args = session.posargs or locations
+    install_with_constraints(
+        session,
+        "flake8",
+        "flake8-bandit",
+        "flake8-black",
+        "flake8-bugbear",
+        "flake8-import-order",
+    )
+    session.run("flake8", *args)
+
+
+@nox.session(python="3.7")
+def safety(session):
+    with tempfile.NamedTemporaryFile() as requirements:
+        session.run(
+            "poetry",
+            "export",
+            "--dev",
+            "--format=requirements.txt",
+            "--without-hashes",
+            f"--output={requirements.name}",
+            external=True,
+        )
+        install_with_constraints(session, "safety")
+        session.run("safety", "check", f"--file={requirements.name}", "--full-report")
+
+
+@nox.session(python="3.7")
+def tests(session):
+    args = session.posargs or ["--cov", "-m", "not e2e"]
+    session.run("poetry", "install", "--no-dev", external=True)
+    install_with_constraints(session, "pytest", "pytest-mock")
+    session.run("pytest", *args)