diff --git a/azure_pull_request.yml b/azure_pull_request.yml
index c607e23..03d63c7 100644
--- a/azure_pull_request.yml
+++ b/azure_pull_request.yml
@@ -1,4 +1,5 @@
 pool:
+  vmImage: ubuntu-latest
   name: Azure Pipelines
   demands: java
 
@@ -21,15 +22,8 @@ steps:
 
 - task: CmdLine@2
   inputs:
-    script: dotnet build --no-incremental
-  displayName: 'Run dotnet build'
-
-- task: DotNetCoreCLI@2
-  displayName: 'Run dotnet test'
-  inputs:
-    command: test
-    projects: '**/*[Tt]ests/*.csproj'
-    arguments: '--configuration $(BuildConfiguration) /p:CollectCoverage=true /p:CoverletOutputFormat=opencover --collect "Code Coverage" /p:Exclude=[xunit.*]*'
+    script: dotnet test --configuration $(BuildConfiguration) /p:CollectCoverage=true /p:CoverletOutputFormat=opencover --collect "Code Coverage" /p:Exclude=[xunit.*]*
+  displayName: 'Run Tests'
 
 - task: SonarSource.sonarcloud.ce096e50-6155-4de8-8800-4221aaeed4a1.SonarCloudAnalyze@1
   displayName: 'Run Code Analysis'
diff --git a/src/Entities/WorkItem.cs b/src/Entities/WorkItem.cs
index 03db258..7a705cc 100644
--- a/src/Entities/WorkItem.cs
+++ b/src/Entities/WorkItem.cs
@@ -95,7 +95,7 @@ public void AddTimeByState(TimeByState timeByState)
 
         public void AddTimesByState(IEnumerable<TimeByState> timesByState)
         {
-            if (timesByState is not null && !timesByState.Any())
+            if (timesByState is null || timesByState?.Any() == false)
                 return;
 
             foreach (var timeByState in timesByState)
diff --git a/src/Extensions/HelperExtenions.cs b/src/Extensions/HelperExtenions.cs
index f4a5859..78dc8da 100644
--- a/src/Extensions/HelperExtenions.cs
+++ b/src/Extensions/HelperExtenions.cs
@@ -25,7 +25,7 @@ public static string ExtractEmail(this string user)
             if (!user.Contains(" <") && !user.TrimEnd().Contains(">"))
                 return user;
 
-            return user.Split("<").LastOrDefault().Split(">").FirstOrDefault();
+            return user.Split("<").LastOrDefault()?.Split(">")?.FirstOrDefault();
         }
 
         public static string ToTextTime(this TimeSpan timeSpan)