update build scripts to ensure tests only run once during CI

appveyor.yml

@@ -18,7 +18,7 @@ build_script:
 test_script:
 - tests\CodeCoverage\CodeCoverage.cmd
 
-after_build:
+after_test:
   - cmd: appveyor PushArtifact "artifacts\SixLabors.ImageSharp.%GitVersion_NuGetVersion%.nupkg"
   - cmd: appveyor PushArtifact "artifacts\SixLabors.ImageSharp.Drawing.%GitVersion_NuGetVersion%.nupkg"
 

build.cmd

@@ -1,5 +1,6 @@
 @echo Off
 
+SET versionCommand=
 if not "%GitVersion_NuGetVersion%" == "" (
     SET versionCommand=/p:packageversion=%GitVersion_NuGetVersion%
     @echo building with version set to '%GitVersion_NuGetVersion%'
@@ -7,16 +8,18 @@ if not "%GitVersion_NuGetVersion%" == "" (
 
 dotnet restore %versionCommand%
 
-
-ECHO Building nuget packages
+ECHO Building projects
 dotnet build -c Release %versionCommand%
+
 if not "%errorlevel%"=="0" goto failure
 
-if not %CI% == "True" (
+if not "%CI%" == "True"  (
+    ECHO NOT on CI server running tests
     dotnet test ./tests/ImageSharp.Tests/ImageSharp.Tests.csproj --no-build -c Release
-    if not "%errorlevel%"=="0" goto failure
 )
+if not "%errorlevel%"=="0" goto failure
 
+ECHO Packaging projects
 dotnet pack ./src/ImageSharp/ -c Release --output ../../artifacts --no-build  %versionCommand%
 if not "%errorlevel%"=="0" goto failure