build list of reporters from factory function

src/coverlet.core/Reporters/ReporterFactory.cs

@@ -5,21 +5,19 @@ namespace Coverlet.Core.Reporters
 {
     public class ReporterFactory
     {
-        private IEnumerable<string> _formats;
+        private string _format;
         private IReporter[] _reporters;
 
-        public ReporterFactory(string formats)
+        public ReporterFactory(string format)
         {
-            _formats = formats.Split(',');
+            _format = format;
             _reporters = new IReporter[] {
                 new JsonReporter(), new LcovReporter(),
                 new OpenCoverReporter(), new CoberturaReporter()
             };
         }
 
-        public IEnumerable<IReporter> CreateReporters()
-        {
-            return _reporters.Where(r => _formats.Contains(r.Format));
-        }
+        public IReporter CreateReporter()
+            => _reporters.FirstOrDefault(r => r.Format == _format);
     }
 }

src/coverlet.msbuild.tasks/CoverageResultTask.cs

@@ -50,15 +50,16 @@ public override bool Execute()
                 if (!Directory.Exists(directory))
                     Directory.CreateDirectory(directory);
 
-                var reporters = new List<IReporter>(new ReporterFactory(_format).CreateReporters());
-                if (reporters.Count != _format.Split(',').Length)
-                    throw new Exception($"Specified output format '{_format}' is not supported");
-
-                foreach(var reporter in reporters)
+                var formats = _format.Split(',');
+                foreach(var format in formats)
                 {
-                    var reportFilename = _filename + "." + reporter.Extension;
-                    Console.WriteLine($"  Generating report '{reportFilename}'");
-                    File.WriteAllText(reportFilename, reporter.Report(result));
+                    var reporter = new ReporterFactory(format).CreateReporter();
+                    if (reporter == null)
+                        throw new Exception($"Specified output format '{format}' is not supported");
+
+                    var report = _filename + "." + reporter.Extension;
+                    Console.WriteLine($"  Generating report '{report}'");
+                    File.WriteAllText(report, reporter.Report(result));
                 }
 
                 double total = 0;

src/coverlet.msbuild/coverlet.msbuild.props

@@ -1,15 +1,13 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 
   <PropertyGroup>
-
     <CoverletOutputFormat Condition="$(CoverletOutputFormat) == ''">json</CoverletOutputFormat>
     <CoverletOutputDirectory Condition="$(CoverletOutputDirectory) == ''">$(MSBuildProjectDirectory)</CoverletOutputDirectory>
     <CoverletOutputName Condition=" '$(CoverletOutputName)' == '' ">coverage</CoverletOutputName>
     <CoverletOutput>$([MSBuild]::EnsureTrailingSlash('$(CoverletOutputDirectory)'))$(CoverletOutputName)</CoverletOutput>
     <Exclude Condition="$(Exclude) == ''"></Exclude>
     <Threshold Condition="$(Threshold) == ''">0</Threshold>
     <CollectCoverage Condition="$(CollectCoverage) == ''">false</CollectCoverage>
-
   </PropertyGroup>
 
 </Project>

test/coverlet.core.tests/Reporters/ReporterFactoryTests.cs

@@ -6,41 +6,13 @@ namespace Coverlet.Core.Reporters.Tests
     public class ReporterFactoryTests
     {
         [Fact]
-        public void TestCreateReportersWithSingleFormat()
+        public void TestCreateReporter()
         {
-            Assert.Collection(
-                new ReporterFactory("json").CreateReporters(),
-                reporter => Assert.IsType<JsonReporter>(reporter));
-            Assert.Collection(
-                new ReporterFactory("lcov").CreateReporters(),
-                reporter => Assert.IsType<LcovReporter>(reporter));
-            Assert.Collection(
-                new ReporterFactory("opencover").CreateReporters(),
-                reporter => Assert.IsType<OpenCoverReporter>(reporter));
-            Assert.Collection(
-                new ReporterFactory("cobertura").CreateReporters(),
-                reporter => Assert.IsType<CoberturaReporter>(reporter));
-            Assert.Empty(new ReporterFactory("").CreateReporters());
-        }
-
-        [Fact]
-        public void TestCreateReportersWithMultipleFormats()
-        {
-            Assert.Collection(
-                new ReporterFactory("json,lcov").CreateReporters(),
-                reporter => Assert.IsType<JsonReporter>(reporter),
-                reporter => Assert.IsType<LcovReporter>(reporter));
-            Assert.Collection(
-                new ReporterFactory("json,lcov,opencover").CreateReporters(),
-                reporter => Assert.IsType<JsonReporter>(reporter),
-                reporter => Assert.IsType<LcovReporter>(reporter),
-                reporter => Assert.IsType<OpenCoverReporter>(reporter));
-            Assert.Collection(
-                new ReporterFactory("json,lcov,opencover,cobertura").CreateReporters(),
-                reporter => Assert.IsType<JsonReporter>(reporter),
-                reporter => Assert.IsType<LcovReporter>(reporter),
-                reporter => Assert.IsType<OpenCoverReporter>(reporter),
-                reporter => Assert.IsType<CoberturaReporter>(reporter));
+            Assert.Equal(typeof(JsonReporter), new ReporterFactory("json").CreateReporter().GetType());
+            Assert.Equal(typeof(LcovReporter), new ReporterFactory("lcov").CreateReporter().GetType());
+            Assert.Equal(typeof(OpenCoverReporter), new ReporterFactory("opencover").CreateReporter().GetType());
+            Assert.Equal(typeof(CoberturaReporter), new ReporterFactory("cobertura").CreateReporter().GetType());
+            Assert.Null(new ReporterFactory("").CreateReporter());
         }
     }
 }