Add coverage summaries in Actions (#1052)

Add code coverage summaries to the GitHub Actions workflow logs.

src/Polly.Specs/Polly.Specs.csproj

@@ -30,8 +30,18 @@
     <Threshold>75,60,70</Threshold>
   </PropertyGroup>
 
+  <PropertyGroup Condition=" '$(CollectCoverage)' == 'true' ">
+    <ReportGeneratorOutputMarkdown Condition=" '$(ReportGeneratorOutputMarkdown)' == '' AND '$(GITHUB_SHA)' != '' ">true</ReportGeneratorOutputMarkdown>
+    <ReportGeneratorReportTypes>HTML</ReportGeneratorReportTypes>
+    <ReportGeneratorReportTypes Condition=" '$(ReportGeneratorOutputMarkdown)' == 'true' ">$(ReportGeneratorReportTypes);MarkdownSummaryGitHub</ReportGeneratorReportTypes>
+    <ReportGeneratorTargetDirectory>$([System.IO.Path]::Combine($(OutputPath), 'coverage-reports'))</ReportGeneratorTargetDirectory>
+    <_MarkdownSummaryPrefix>&lt;details&gt;&lt;summary&gt;:chart_with_upwards_trend: &lt;b&gt;$(AssemblyName) Code Coverage report&lt;/b&gt; %28$(TargetFramework)%29&lt;/summary&gt;</_MarkdownSummaryPrefix>
+    <_MarkdownSummarySuffix>&lt;/details&gt;</_MarkdownSummarySuffix>
+  </PropertyGroup>
+
   <Target Name="GenerateCoverageReports" AfterTargets="GenerateCoverageResultAfterTest" Condition=" '$(CollectCoverage)' == 'true' ">
-    <ReportGenerator ReportFiles="@(CoverletReport)" ReportTypes="Cobertura;Html" TargetDirectory="$([System.IO.Path]::Combine($(MSBuildThisFileDirectory), 'coverage-reports'))" />
+    <ReportGenerator ReportFiles="@(CoverletReport)" ReportTypes="$(ReportGeneratorReportTypes)" Tag="$(TargetFramework)" TargetDirectory="$(ReportGeneratorTargetDirectory)" Title="$(AssemblyName)" VerbosityLevel="Warning" />
+    <Exec Condition=" '$(ReportGeneratorOutputMarkdown)' == 'true' " Command="pwsh -Command %22('$(_MarkdownSummaryPrefix)' + [System.Environment]::NewLine + [System.Environment]::NewLine + (Get-Content $([System.IO.Path]::Combine($(ReportGeneratorTargetDirectory), 'SummaryGithub.md')) | Out-String) + [System.Environment]::NewLine + [System.Environment]::NewLine + '$(_MarkdownSummarySuffix)') >> $(GITHUB_STEP_SUMMARY)%22" />
   </Target>
 
 </Project>