Set up CI with Azure Pipelines

Run unit tests.

azure-pipelines.yml

@@ -0,0 +1,55 @@
+# Python package
+# Create and test a Python package on multiple Python versions.
+# Add steps that analyze code, save the dist with the build record, publish to a PyPI-compatible index, and more:
+# https://docs.microsoft.com/azure/devops/pipelines/languages/python
+
+jobs:
+
+- job: 'Test'
+  pool:
+    vmImage: 'Ubuntu 16.04'
+  strategy:
+    matrix:
+      Python27:
+        python.version: '2.7'
+      Python35:
+        python.version: '3.5'
+      Python36:
+        python.version: '3.6'
+      Python37:
+        python.version: '3.7'
+    maxParallel: 4
+
+  steps:
+  - task: UsePythonVersion@0
+    inputs:
+      versionSpec: '$(python.version)'
+      architecture: 'x64'
+
+  - script: python -m pip install --upgrade pip && pip install -r requirements.txt
+    displayName: 'Install dependencies'
+
+  - script: |
+      pip install pytest
+      pytest tests --doctest-modules --junitxml=junit/test-results.xml
+    displayName: 'pytest'
+
+  - task: PublishTestResults@2
+    inputs:
+      testResultsFiles: '**/test-results.xml'
+      testRunTitle: 'Python $(python.version)'
+    condition: succeededOrFailed()
+
+- job: 'Publish'
+  dependsOn: 'Test'
+  pool:
+    vmImage: 'Ubuntu 16.04'
+
+  steps:
+  - task: UsePythonVersion@0
+    inputs:
+      versionSpec: '3.x'
+      architecture: 'x64'
+
+  - script: python setup.py sdist
+    displayName: 'Build sdist'