add postgres and older flake8 requirement

Author: Joey Leingang

.circleci/config.yml

@@ -13,6 +13,12 @@ aliases:
       TEST_REPORTS: /tmp/test-reports
     steps:
       - checkout
+      - run:
+          name: Install postgres
+          command: |
+            sudo apt-get update && \
+              sudo apt-get install \
+                postgresql-9.6
       - run:
           <<: *dependencies
       - run: make test

test_requirements.txt

@@ -2,7 +2,8 @@
 # Requirements needed for running the test suite.
 astroid==2.0.4
 coverage==4.5.1
-flake8-bugbear==18.8.0
+flake8-bugbear==18.8.0;python_version>"3.4"
+flake8-bugbear==17.12.0;python_version<"3.5"
 flake8-commas==2.0.0
 flake8-comprehensions==1.4.1
 flake8-import-order==0.18