Display only latest pre-release version from Get-Package cmdlet.

src/AddIns/Misc/PackageManagement/Cmdlets/Project/Src/GetPackageCmdlet.cs

@@ -77,11 +77,16 @@ namespace ICSharpCode.PackageManagement.Cmdlets
 		protected override void ProcessRecord()
 		{
 			ValidateParameters();
+			IEnumerable<IPackage> packages = GetFilteredPackages();
+			WritePackagesToOutputPipeline(packages);
+		}
 		
+		IEnumerable<IPackage> GetFilteredPackages()
+		{
 			IQueryable<IPackage> packages = GetPackages();
 			packages = OrderPackages(packages);
-			packages = SelectPackageRange(packages);
-			WritePackagesToOutputPipeline(packages);
+			IEnumerable<IPackage> distinctPackages = packages.DistinctLast(PackageEqualityComparer.Id);
+			return SelectPackageRange(distinctPackages);
 		}
 		
 		void ValidateParameters()
@@ -119,7 +124,7 @@ namespace ICSharpCode.PackageManagement.Cmdlets
 			return packages.OrderBy(package => package.Id);
 		}
 		
-		IQueryable<IPackage> SelectPackageRange(IQueryable<IPackage> packages)
+		IEnumerable<IPackage> SelectPackageRange(IEnumerable<IPackage> packages)
 		{
 			if (skip.HasValue) {
 				packages = packages.Skip(skip.Value);
@@ -210,7 +215,7 @@ namespace ICSharpCode.PackageManagement.Cmdlets
 			return null;
 		}
 		
-		void WritePackagesToOutputPipeline(IQueryable<IPackage> packages)
+		void WritePackagesToOutputPipeline(IEnumerable<IPackage> packages)
 		{
 			foreach (IPackage package in packages) {
 				WriteObject(package);

src/AddIns/Misc/PackageManagement/Cmdlets/Test/Src/GetPackageCmdletTests.cs

@@ -568,5 +568,26 @@ namespace PackageManagement.Cmdlets.Tests
 			
 			CollectionAssert.AreEqual(expectedPackages, actualPackages);
 		}
+		
+		[Test]
+		public void ProcessRecord_ListAvailableAndPrereleasePackagesWithFilterWhenMultiplePackageVersions_ReturnsLatestPrereleasePackages()
+		{
+			CreateCmdlet();
+			FakePackageRepository repository = fakeRegisteredPackageRepositories.FakePackageRepository;
+			repository.AddFakePackageWithVersion("B", "2.0.1-beta");
+			FakePackage expectedPackage = repository.AddFakePackageWithVersion("B", "2.1.0-beta");
+			EnableListAvailableParameter();
+			EnablePrereleaseParameter();
+			SetFilterParameter("B");
+			
+			RunCmdlet();
+			
+			List<object> actualPackages = fakeCommandRuntime.ObjectsPassedToWriteObject;
+			var expectedPackages = new FakePackage[] {
+				expectedPackage
+			};
+			
+			CollectionAssert.AreEqual(expectedPackages, actualPackages);
+		}
 	}
 }