Fix for NPE in Orchestrator (#335)

* Test, that fails

* Fix for the issue

* Removed unnecessary null check

Author: agr

src/NuGet.Services.Validation.Orchestrator/ValidationStorageService.cs

@@ -137,12 +137,13 @@ private void TrackValidationStatus(PackageValidation packageValidation)
                packageValidation.Type,
                isSuccess);
 
+            var issues = (packageValidation.PackageValidationIssues ?? Enumerable.Empty<PackageValidationIssue>()).ToList();
             _telemetryService.TrackValidationIssueCount(
-                packageValidation.PackageValidationIssues.Count,
+                issues.Count,
                 packageValidation.Type,
                 isSuccess);
 
-            foreach (var issue in packageValidation?.PackageValidationIssues ?? Enumerable.Empty<PackageValidationIssue>())
+            foreach (var issue in issues)
             {
                 _telemetryService.TrackValidationIssue(packageValidation.Type, issue.IssueCode);
 

tests/NuGet.Services.Validation.Orchestrator.Tests/ValidationStorageServiceFacts.cs

@@ -250,6 +250,23 @@ public async Task DoesNotEmitTelemtryForIncomplete()
                 // Assert
                 _telemetryService.VerifyAll();
             }
+
+            [Theory]
+            [InlineData(ValidationStatus.Failed)]
+            [InlineData(ValidationStatus.Incomplete)]
+            [InlineData(ValidationStatus.Succeeded)]
+            public async Task DoesNotThrowWhenPackageValidationIssuesIsNull(ValidationStatus validationStatus)
+            {
+                // Arrange
+                _packageValidation.PackageValidationIssues = null;
+                var validationResult = new ValidationResult(validationStatus);
+
+                // Act
+                var ex = await Record.ExceptionAsync(async() => await ExecuteAsync(validationResult));
+
+                // Assert
+                Assert.Null(ex);
+            }
         }
 
         public abstract class Facts