Add Python 3.7 tests in Circle CI (#711)

Author: danielkza

.circleci/config.yml

@@ -24,13 +24,20 @@ workflows:
       - functional-test-36:
           requires:
             - unit-test-36
-            - functional-test-27
             - functional-test-35
+      - unit-test-37:
+          requires:
+            - lint
+      - functional-test-37:
+          requires:
+            - unit-test-37
+            - functional-test-36
       - cleanup-functional-buckets:
           requires:
             - functional-test-27
             - functional-test-35
             - functional-test-36
+            - functional-test-37
 
 jobs:
   lint:
@@ -46,31 +53,30 @@ jobs:
   unit-test-27:
     docker:
       - image: circleci/python:2.7
-    steps:
+    steps: &unit_test_steps
       - checkout
       - run: sudo python setup.py install
       - run: sudo make test-unit
 
   unit-test-35:
     docker:
       - image: circleci/python:3.5
-    steps:
-      - checkout
-      - run: sudo python setup.py install
-      - run: sudo make test-unit
+    steps: *unit_test_steps
 
   unit-test-36:
     docker:
       - image: circleci/python:3.6
-    steps:
-      - checkout
-      - run: sudo python setup.py install
-      - run: sudo make test-unit
+    steps: *unit_test_steps
+
+  unit-test-37:
+    docker:
+      - image: circleci/python:3.7
+    steps: *unit_test_steps
 
   functional-test-27:
     docker:
       - image: circleci/python:2.7
-    steps:
+    steps: &functional_test_steps
       - checkout
       - run:
           command: |
@@ -91,44 +97,17 @@ jobs:
   functional-test-35:
     docker:
       - image: circleci/python:3.5
-    steps:
-      - checkout
-      - run:
-          command: |
-            git clone https://github.com/bats-core/bats-core.git
-            cd bats-core
-            git checkout v1.0.2
-            sudo ./install.sh /usr/local
-            bats --version
-      - run: sudo python setup.py install
-      - run:
-          command: |
-            export TERM=xterm
-            export AWS_DEFAULT_REGION=us-east-1
-            export STACKER_NAMESPACE=cloudtools-functional-tests-$CIRCLE_BUILD_NUM
-            export STACKER_ROLE=arn:aws:iam::459170252436:role/cloudtools-functional-tests-sta-FunctionalTestRole-1M9HFJ9VQVMFX
-            sudo -E make test-functional
+    steps: *functional_test_steps
 
   functional-test-36:
     docker:
       - image: circleci/python:3.6
-    steps:
-      - checkout
-      - run:
-          command: |
-            git clone https://github.com/bats-core/bats-core.git
-            cd bats-core
-            git checkout v1.0.2
-            sudo ./install.sh /usr/local
-            bats --version
-      - run: sudo python setup.py install
-      - run:
-          command: |
-            export TERM=xterm
-            export AWS_DEFAULT_REGION=us-east-1
-            export STACKER_NAMESPACE=cloudtools-functional-tests-$CIRCLE_BUILD_NUM
-            export STACKER_ROLE=arn:aws:iam::459170252436:role/cloudtools-functional-tests-sta-FunctionalTestRole-1M9HFJ9VQVMFX
-            sudo -E make test-functional
+    steps: *functional_test_steps
+
+  functional-test-37:
+    docker:
+      - image: circleci/python:3.7
+    steps: *functional_test_steps
 
   cleanup-functional-buckets:
     docker: