Add integration tests

Setup integration test matrix in CircleCI.
* Update README integration testing list.

Signed-off-by: Ben Kochie <superq@gmail.com>

.circleci/config.yml

@@ -20,6 +20,30 @@ jobs:
     - prometheus/store_artifact:
         file: postgres_exporter
 
+  integration:
+    docker:
+    - image: circleci/golang:1.15
+    - image: << parameters.postgres_image >>
+      environment:
+        POSTGRES_DB: circle_test
+        POSTGRES_USER: postgres
+        POSTGRES_PASSWORD: test
+
+    parameters:
+      postgres_image:
+        type: string
+
+    environment:
+      DATA_SOURCE_NAME: 'postgresql://postgres:test@localhost:5432/circle_test?sslmode=disable'
+      GOOPTS: '-v -tags integration'
+
+    steps:
+    - checkout
+    - setup_remote_docker
+    - run: docker version
+    - run: make build
+    - run: make test
+
 workflows:
   version: 2
   postgres_exporter:
@@ -28,6 +52,17 @@ workflows:
         filters:
           tags:
             only: /.*/
+    - integration:
+        matrix:
+          parameters:
+            postgres_image:
+            - circleci/postgres:9.4
+            - circleci/postgres:9.5
+            - circleci/postgres:9.6
+            - circleci/postgres:10
+            - circleci/postgres:11
+            - circleci/postgres:12
+            - circleci/postgres:13
     - prometheus/build:
         name: build
         filters:

README.md

@@ -7,7 +7,7 @@
 
 Prometheus exporter for PostgreSQL server metrics.
 
-CI Tested PostgreSQL versions: `9.4`, `9.5`, `9.6`, `10`, `11`
+CI Tested PostgreSQL versions: `9.4`, `9.5`, `9.6`, `10`, `11`, `12`, `13`
 
 ## Quick Start
 This package is available for Docker: