Add a GitHub workflow to test this thing

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

.github/workflows/test.yml

@@ -0,0 +1,59 @@
+name: Run tests
+
+on: [push, pull_request]
+
+jobs:
+  windows:
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: download Git for Windows' git-sdk-64
+      shell: bash
+      run: |
+        ## Get artifact
+        urlbase=https://dev.azure.com/git-for-windows/git/_apis/build/builds
+        id=$(curl "$urlbase?definitions=29&statusFilter=completed&resultFilter=succeeded&\$top=1" |
+          jq -r ".value[] | .id")
+        download_url="$(curl "$urlbase/$id/artifacts" |
+          jq -r '.value[] | select(.name == "git-sdk-64-full-sdk").resource.downloadUrl')"
+        curl --connect-timeout 10 --retry 5 --retry-delay 0 --retry-max-time 240 \
+          -o artifacts.zip "$download_url"
+
+        ## Unzip and remove artifact
+        unzip -v artifacts.zip
+        mkdir git-sdk-64
+        unzip -p artifacts.zip git-sdk-64-full-sdk/git-sdk-64.tar.xz | tar -C git-sdk-64 -xJf -
+        rm artifacts.zip
+    - name: test
+      shell: powershell
+      env:
+        HOME: ${{runner.workspace}}
+        MSYSTEM: MINGW64
+      run: |
+        & .\git-sdk-64\usr\bin\bash.exe -lc @"
+          cd t &&
+          PYTHONPATH=`$PWD \
+          TEST_SHELL_PATH=/bin/sh \
+          prove -j`$(nproc) t[0-9]*.sh :: -V -x
+        "@
+    - name: print failures
+      if: failure()
+      shell: powershell
+      run: |
+        & .\git-sdk-64\usr\bin\bash.exe -lc @"
+          mkdir failed
+          tar tzvf failed/failed.tar.gz t
+          for out in t/test-results/*.out
+          do
+            printf '\n\n== %s ==\n' \"`$out\"
+            cat \"`$out\"
+          done
+          mv t/trash* t/test-results failed/
+        "@
+    - name: upload failed tests' directories
+      if: failure()
+      uses: actions/upload-artifact@v1
+      with:
+        name: failed-tests-windows
+        path: failed
+