Add mypy build to circleci; Use workflow ID number as dep cache key

.circleci/config.yml

@@ -5,6 +5,9 @@ workflows:
   test:
     jobs:
       - bundle_dependencies-36
+      - mypy_type_check:
+          requires:
+            - bundle_dependencies-36
       - eth_contract_unit:
           requires:
             - bundle_dependencies-36
@@ -31,8 +34,6 @@ workflows:
 
 python_36_base: &python_36_base
     working_directory: ~/nucypher-depends
-    environment:
-      PIPENV_VENV_IN_PROJECT: "True"
     docker:
       - image: circleci/python:3.6
 
@@ -44,22 +45,21 @@ jobs:
       - run:
           name: Install Python Dependencies with Pipenv
           command: |
-            export PIPENV_VENV_IN_PROJECT=True
             pipenv install --three --dev --pre --skip-lock
       - run:
           name: Install Solidity Compiler
           command: pipenv run install_solc
       - save_cache:
           paths:
-            - "./.venv"
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+            - "~/.local/share/virtualenvs/"
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
 
   blockchain_interface_unit:
     <<: *python_36_base
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Blockchain Interface Tests
           command: pipenv run pytest --cov=nucypher/blockchain/eth -v --runslow tests/blockchain/eth/interfaces tests/blockchain/eth/entities
@@ -70,7 +70,7 @@ jobs:
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Ethereum Contract Unit Tests
           command: |
@@ -83,7 +83,7 @@ jobs:
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Crypto Character Tests
           command: pipenv run pytest --cov=nucypher/crypto -v --runslow tests/crypto
@@ -93,7 +93,7 @@ jobs:
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Network Tests
           command: pipenv run pytest --cov=nucypher/network -v --runslow tests/network
@@ -103,7 +103,7 @@ jobs:
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Keystore Tests
           command: pipenv run pytest --cov=nucypher/keystore -v --runslow tests/keystore
@@ -113,7 +113,7 @@ jobs:
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Character Tests
           command: pipenv run pytest --cov=nucypher/characters -v --runslow tests/characters
@@ -123,8 +123,20 @@ jobs:
     steps:
       - checkout
       - restore_cache:
-          key: v2-deps-{{ .Branch }}-{{ checksum "Pipfile" }}
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
       - run:
           name: Ethereum Inter-Contract Integration Test
           command: |
             pipenv run pytest -v --runslow tests/blockchain/eth/contracts/integration
+
+  mypy_type_check:
+    <<: *python_36_base
+    steps:
+      - checkout
+      - restore_cache:
+          key: v1-deps-{{ .Environment.CIRCLE_WORKFLOW_ID }}-{{ checksum "Pipfile" }}
+      - run:
+          name: Run Mypy Static Type Checks
+          command: pipenv run mypy --xslt-html-report ./mypy_report ./nucypher
+      - store_artifacts:
+          path: ./mypy_report