Fix null reference when installing unknown NuGet package.

If a NuGet package is not found when installing it via the Package Management Console or
when a project template tries to install the package an exception is thrown indicating the
actual problem instead of a null reference exception being thrown.

src/AddIns/Misc/PackageManagement/Project/Src/Design/FakePackageManagementProject.cs

@@ -208,5 +208,10 @@ namespace ICSharpCode.PackageManagement.Design
 		{
 			FakePackages.Add(new FakePackage(id));
 		}
+		
+		public void AddFakePackageToSourceRepository(string packageId)
+		{
+			FakeSourceRepository.AddFakePackage(packageId);
+		}
 	}
 }

src/AddIns/Misc/PackageManagement/Project/Src/ProcessPackageAction.cs

@@ -99,6 +99,15 @@ namespace ICSharpCode.PackageManagement
 			if (Package == null) {
 				Package = Project.SourceRepository.FindPackage(PackageId, PackageVersion);
 			}
+			if (Package == null) {
+				ThrowPackageNotFoundError(PackageId);
+			}
+		}
+		
+		void ThrowPackageNotFoundError(string packageId)
+		{
+			string message = String.Format("Unable to find package '{0}'.", packageId);
+			throw new ApplicationException(message);
 		}
 		
 		protected bool PackageIdExistsInProject()

src/AddIns/Misc/PackageManagement/Test/Src/InstallPackageActionTests.cs

@@ -148,6 +148,7 @@ namespace PackageManagement.Tests
 		{
 			CreateAction();
 			fakeProject.AddFakeInstallOperation();
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			installPackageHelper.InstallPackageById("PackageId");
 			
 			var actualOperations = action.Operations;
@@ -174,6 +175,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdAndSourceAndProjectPassedAndIgnoreDependenciesIsTrue_DependenciesIgnoredWhenGettingPackageOperations()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			installPackageHelper.IgnoreDependencies = true;
 			installPackageHelper.InstallPackageById("PackageId");
 			
@@ -186,6 +188,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdAndSourceAndProjectPassedAndAllowPrereleaseVersionsIsTrue_PrereleaseVersionsAllowedWhenGettingPackageOperations()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			installPackageHelper.AllowPrereleaseVersions = true;
 			installPackageHelper.InstallPackageById("PackageId");
 			
@@ -198,6 +201,7 @@ namespace PackageManagement.Tests
 		public void InstallPackage_PackageIdAndSourceAndProjectPassedAndIgnoreDependenciesIsFalse_DependenciesNotIgnoredWhenGettingPackageOperations()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			installPackageHelper.IgnoreDependencies = false;
 			installPackageHelper.InstallPackageById("PackageId");
 			
@@ -210,6 +214,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdAndSourceAndProjectPassedAndAllowPrereleaseVersionsIsFalse_PrereleaseVersionsNotAllowedWhenGettingPackageOperations()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			installPackageHelper.AllowPrereleaseVersions = false;
 			installPackageHelper.InstallPackageById("PackageId");
 			
@@ -245,6 +250,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasInitPowerShellScript_ReturnsTrue()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			AddInstallOperationWithFile(@"tools\init.ps1");
 			
@@ -257,6 +263,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasNoFiles_ReturnsFalse()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			action.Operations = new List<PackageOperation>();
 			
@@ -269,6 +276,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasInitPowerShellScriptInUpperCase_ReturnsTrue()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			AddInstallOperationWithFile(@"tools\INIT.PS1");
 			
@@ -281,6 +289,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasInstallPowerShellScriptInUpperCase_ReturnsTrue()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			AddInstallOperationWithFile(@"tools\INSTALL.PS1");
 			
@@ -293,6 +302,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasUninstallPowerShellScriptInUpperCase_ReturnsTrue()
 		{
 			CreateAction();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			AddInstallOperationWithFile(@"tools\UNINSTALL.PS1");
 			
@@ -331,5 +341,16 @@ namespace PackageManagement.Tests
 			
 			Assert.AreEqual(expectedPackage, actualPackage);
 		}
+		
+		[Test]
+		public void Execute_PackageIdSpecifiedButDoesNotExistInRepository_ExceptionThrown()
+		{
+			CreateAction();
+			action.PackageId = "UnknownId";
+			
+			Exception ex = Assert.Throws(typeof(ApplicationException), () => action.Execute());
+			
+			Assert.AreEqual("Unable to find package 'UnknownId'.", ex.Message);
+		}
 	}
 }

src/AddIns/Misc/PackageManagement/Test/Src/UninstallPackageActionTests.cs

@@ -75,7 +75,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageObjectPassedAndForceRemoveIsFalse_PackageIsNotForcefullyRemoved()
 		{
 			CreateAction();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			uninstallPackageHelper.ForceRemove = false;
 			uninstallPackageHelper.UninstallPackageById("PackageId");
 			
@@ -88,7 +88,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageObjectPassedAndForceRemoveIsTrue_PackageIsForcefullyRemoved()
 		{
 			CreateAction();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			uninstallPackageHelper.ForceRemove = true;
 			uninstallPackageHelper.UninstallPackageById("PackageId");
 			
@@ -101,7 +101,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageObjectPassedAndRemoveDependenciesIsFalse_PackageDependenciesAreNotRemoved()
 		{
 			CreateAction();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			uninstallPackageHelper.RemoveDependencies = false;
 			uninstallPackageHelper.UninstallPackageById("PackageId");
 			
@@ -114,7 +114,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageObjectPassedAndRemoveDependenciesIsTrue_PackageDependenciesAreRemoved()
 		{
 			CreateAction();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			uninstallPackageHelper.RemoveDependencies = true;
 			uninstallPackageHelper.UninstallPackageById("PackageId");
 			
@@ -127,7 +127,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdSpecifiedAndForceRemoveIsTrue_PackageIsForcefullyRemoved()
 		{
 			CreateAction();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			uninstallPackageHelper.ForceRemove = true;
 			uninstallPackageHelper.UninstallPackageById("PackageId");
 			
@@ -140,7 +140,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdSpecifiedAndRemoveDependenciesIsTrue_PackageDependenciesAreRemoved()
 		{
 			CreateAction();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			uninstallPackageHelper.RemoveDependencies = true;
 			uninstallPackageHelper.UninstallPackageById("PackageId");
 			

src/AddIns/Misc/PackageManagement/Test/Src/UpdatePackageActionTests.cs

@@ -166,7 +166,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdAndSourceAndProjectPassedAndUpdateDependenciesIsTrue_DependenciesUpdatedWhenUpdatingPackage()
 		{
 			CreateSolution();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			updatePackageHelper.UpdateDependencies = true;
 			updatePackageHelper.UpdatePackageById("PackageId");
 			
@@ -179,7 +179,7 @@ namespace PackageManagement.Tests
 		public void Execute_PackageIdAndSourceAndProjectPassedAndUpdateDependenciesIsFalse_DependenciesNotUpdatedWhenGettingPackageOperations()
 		{
 			CreateSolution();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			updatePackageHelper.UpdateDependencies = false;
 			updatePackageHelper.UpdatePackageById("PackageId");
 			
@@ -192,7 +192,7 @@ namespace PackageManagement.Tests
 		public void Execute_UpdatedDepdenciesIsFalseAndNoPackageOperations_DependenciesIgnoredWhenGettingPackageOperations()
 		{
 			CreateSolution();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			updatePackageHelper.UpdateDependencies = false;
 			updatePackageHelper.UpdatePackageById("PackageId");
 			
@@ -205,7 +205,7 @@ namespace PackageManagement.Tests
 		public void Execute_UpdateDependenciesIsTrueAndNoPackageOperations_DependenciesNotIgnoredWhenGettingPackageOperations()
 		{
 			CreateSolution();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			updatePackageHelper.UpdateDependencies = true;
 			updatePackageHelper.UpdatePackageById("PackageId");
 			
@@ -218,7 +218,7 @@ namespace PackageManagement.Tests
 		public void Execute_AllowPrereleaseVersionsIsFalseAndNoPackageOperations_PrereleaseVersionsNotAllowedWhenGettingPackageOperations()
 		{
 			CreateSolution();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			updatePackageHelper.AllowPrereleaseVersions = false;
 			updatePackageHelper.UpdatePackageById("PackageId");
 			
@@ -231,7 +231,7 @@ namespace PackageManagement.Tests
 		public void Execute_AllowPrereleaseVersionsIsTrueAndNoPackageOperations_PrereleaseVersionsAllowedWhenGettingPackageOperations()
 		{
 			CreateSolution();
-			
+			fakeProject.AddFakePackageToSourceRepository("PackageId");
 			updatePackageHelper.AllowPrereleaseVersions = true;
 			updatePackageHelper.UpdatePackageById("PackageId");
 			
@@ -255,6 +255,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasInitPowerShellScript_ReturnsTrue()
 		{
 			CreateSolution();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			AddInstallOperationWithFile(@"tools\init.ps1");
 			
@@ -267,6 +268,7 @@ namespace PackageManagement.Tests
 		public void HasPackageScriptsToRun_OnePackageInOperationsHasNoFiles_ReturnsFalse()
 		{
 			CreateSolution();
+			fakeProject.AddFakePackageToSourceRepository("Test");
 			action.PackageId = "Test";
 			action.Operations = new List<PackageOperation>();