add functionality to fail build if coverage is below a certain threshold

Author: tonerdo

src/coverlet.msbuild.tasks/CoverageResultTask.cs

@@ -14,6 +14,7 @@ public class CoverageResultTask : Task
     {
         private string _filename;
         private string _format;
+        private int _threshold;
 
         [Required]
         public string Output
@@ -29,6 +30,13 @@ public string OutputFormat
             set { _format = value; }
         }
 
+        [Required]
+        public int Threshold
+        {
+            get { return _threshold; }
+            set { _threshold = value; }
+        }
+
         public override bool Execute()
         {
             try
@@ -59,15 +67,23 @@ public override bool Execute()
 
                 File.WriteAllText(_filename, result.Format(reporter));
 
+                int total = 0;
                 CoverageSummary coverageSummary = new CoverageSummary(result);
                 var summary = coverageSummary.CalculateSummary();
 
                 ConsoleTable table = new ConsoleTable("Module", "Coverage");
                 foreach (var item in summary)
+                {
                     table.AddRow(item.Key, $"{item.Value}%");
+                    total += item.Value;
+                }
 
                 Console.WriteLine();
                 table.Write(Format.Alternative);
+
+                int average = total / summary.Count;
+                if (average < _threshold)
+                    return false;
             }
             catch (Exception ex)
             {

src/coverlet.msbuild/coverlet.msbuild.props

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <CoverletOutputFormat Condition="$(CoverletOutputFormat) == ''">json</CoverletOutputFormat>
     <CoverletOutputDirectory Condition="$(CoverletOutputDirectory) == ''">$(MSBuildProjectDirectory)</CoverletOutputDirectory>
-
+    <Threshold Condition="$(Threshold) == ''">0</Threshold>
     <CoverletOutputExtension Condition="$(CoverletOutputFormat) == 'lcov'">.info</CoverletOutputExtension>
     <CoverletOutputExtension Condition="$(CoverletOutputFormat) == 'opencover'">.xml</CoverletOutputExtension>
     <CoverletOutputExtension Condition="$(CoverletOutputFormat) != 'lcov' and $(CoverletOutputFormat) != 'opencover'">.json</CoverletOutputExtension>

src/coverlet.msbuild/coverlet.msbuild.targets

@@ -19,7 +19,8 @@
     <Coverlet.MSbuild.Tasks.CoverageResultTask
       Condition="$(CollectCoverage) == 'true'"
       Output="$(CoverletOutput)"
-      OutputFormat="$(CoverletOutputFormat)" />
+      OutputFormat="$(CoverletOutputFormat)"
+      Threshold="$(Threshold)" />
   </Target>
 
 </Project>