Add appveyor for testing on windows

Author: bjornstar

.appveyor.yml

@@ -0,0 +1,20 @@
+build: off
+
+environment:
+  matrix:
+    - nodejs_version: '14'
+    - nodejs_version: '12'
+    - nodejs_version: '10'
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - npm install
+
+test_script:
+  - node test | tap-xunit | tee test-results.xml
+
+after_test:
+  - ps: |
+      $wc = New-Object 'System.Net.WebClient'
+      $wc.UploadFile("https://ci.appveyor.com/api/testresults/junit/$($env:APPVEYOR_JOB_ID)", (Resolve-Path .\test-results.xml))
+      Push-AppveyorArtifact (Resolve-Path '.\test-results.xml')

package.json

@@ -48,6 +48,7 @@
     "lint-staged": "^10.5.4",
     "prettier": "^2.2.1",
     "tap": "^15.0.2",
+    "tap-xunit": "^2.4.1",
     "touch": "^3.1.0",
     "ts-node": "^9.1.1",
     "typescript": "^4.1.5"