Add Windows test script.

.github/workflows/build.yml

@@ -60,3 +60,5 @@ jobs:
       run: nuget restore pdfio.sln
     - name: Build PDFio
       run: msbuild pdfio.sln
+    - name: Test PDFio
+      run: .\runtests.bat x64\Debug

runtests.bat

@@ -0,0 +1,16 @@
+:: Script to run unit test program
+::
+:: Usage:
+::
+::   .\runtests.bat x64\{Debug|Release}
+::
+
+:: Copy dependent DLLs to the named build directory
+echo Copying DLLs
+copy packages\zlib_native.redist.1.2.11\build\native\bin\x64\Debug\*.dll %1
+copy packages\zlib_native.redist.1.2.11\build\native\bin\x64\Release\*.dll %1
+
+:: Run unit test program
+echo Running %1\testpdfio.exe
+cd %1
+testpdfio.exe