Add possibility to limit posted issues for a specific provider (#158)

This pullrequest introduces a new property ProviderType to the IPullRequestDiscussionThread interface.
The ProviderType is being used to restrict each providers issues by either a maximum limit across all runs or a limit for each individual run.

Co-authored-by: janniksam <jannik.sam@gmail.com>
Co-authored-by: Pascal Berger <bep@bbtsoftware.ch>

src/Cake.Issues.PullRequests.Tests/IIssueExtensionsTests.cs

@@ -0,0 +1,127 @@
+namespace Cake.Issues.PullRequests.Tests
+{
+    using System.Collections.Generic;
+    using System.Linq;
+    using Cake.Issues.Testing;
+    using Shouldly;
+    using Xunit;
+
+    public sealed class IIssueExtensionsTests
+    {
+        public sealed class TheSortWithDefaultPriorizationMethod
+        {
+            [Fact]
+            public void Should_Throw_If_Issues_Are_Null()
+            {
+                // Given
+                IEnumerable<IIssue> issues = null;
+
+                // When
+                var result =
+                    Record.Exception(() =>
+                        issues.SortWithDefaultPriorization());
+
+                // Then
+                result.IsArgumentNullException("issues");
+            }
+
+            [Fact]
+            public void Should_Order_By_Priority()
+            {
+                // Given
+                var issue1 =
+                    IssueBuilder
+                        .NewIssue("Message Foo", "ProviderType Foo", "ProviderName Foo")
+                        .InFile(@"src\Cake.Issues.Tests\FakeIssueProvider.cs", 10)
+                        .OfRule("Rule Foo")
+                        .WithPriority(IssuePriority.Warning)
+                        .Create();
+                var issue2 =
+                    IssueBuilder
+                        .NewIssue("Message Bar", "ProviderType Bar", "ProviderName Bar")
+                        .InFile(@"src\Cake.Issues.Tests\FakeIssueProvider.cs", 12)
+                        .OfRule("Rule Bar")
+                        .WithPriority(IssuePriority.Error)
+                        .Create();
+                var issues =
+                    new List<IIssue>
+                    {
+                        issue1,
+                        issue2,
+                    };
+
+                // When
+                var result = issues.SortWithDefaultPriorization();
+
+                // Then
+                result.First().ShouldBe(issue2);
+                result.Last().ShouldBe(issue1);
+            }
+
+            [Fact]
+            public void Should_Order_By_Existance_Of_FilePath()
+            {
+                // Given
+                var issue1 =
+                    IssueBuilder
+                        .NewIssue("Message Foo", "ProviderType Foo", "ProviderName Foo")
+                        .OfRule("Rule Foo")
+                        .WithPriority(IssuePriority.Warning)
+                        .Create();
+                var issue2 =
+                    IssueBuilder
+                        .NewIssue("Message Bar", "ProviderType Bar", "ProviderName Bar")
+                        .InFile(@"src\Cake.Issues.Tests\FakeIssueProvider.cs", 12)
+                        .OfRule("Rule Bar")
+                        .WithPriority(IssuePriority.Warning)
+                        .Create();
+                var issues =
+                    new List<IIssue>
+                    {
+                        issue1,
+                        issue2,
+                    };
+
+                // When
+                var result = issues.SortWithDefaultPriorization();
+
+                // Then
+                result.First().ShouldBe(issue2);
+                result.Last().ShouldBe(issue1);
+            }
+
+            [Fact]
+            public void Should_Order_By_FilePath()
+            {
+                // Given
+                var issue1 =
+                    IssueBuilder
+                        .NewIssue("Message Foo", "ProviderType Foo", "ProviderName Foo")
+                        .OfRule("Rule Foo")
+                        .InFile(@"src\Cake.Issues.Tests\B.cs", 12)
+                        .WithPriority(IssuePriority.Warning)
+                        .Create();
+                var issue2 =
+                    IssueBuilder
+                        .NewIssue("Message Bar", "ProviderType Bar", "ProviderName Bar")
+                        .InFile(@"src\Cake.Issues.Tests\A.cs", 12)
+                        .OfRule("Rule Bar")
+                        .WithPriority(IssuePriority.Warning)
+                        .Create();
+                var issues =
+                    new List<IIssue>
+                    {
+                        issue1,
+                        issue2,
+                    };
+
+                // When
+                var result = issues.SortWithDefaultPriorization();
+
+                // Then
+                result.First().ShouldBe(issue2);
+                result.Last().ShouldBe(issue1);
+            }
+        }
+    }
+}