Changes from review

src/NUnitEngine/nunit.engine.api/TestPackage.cs

@@ -54,7 +54,7 @@ public TestPackage(IList<string> testFiles)
         private void InitializeSubPackages(IList<string> testFiles)
         {
             foreach (string testFile in testFiles)
-                SubPackages.Add(new TestPackage().Named(testFile));
+                AddSubPackage(testFile);
         }
 
         private static int _nextID = 0;
@@ -87,29 +87,6 @@ public string Name
         /// </summary>
         public string FullName { get; private set; }
 
-        /// <summary>
-        /// Fluent modifier intended for use with the default
-        /// constructor to assign a name to a package. This
-        /// should be used for creating subpackages as it is
-        /// the only way to assign a name to the package.
-        /// </summary>
-        /// <param name="fileName">The name or path of the file.</param>
-        /// <returns>The current instance.</returns>
-        /// <example>
-        /// var subpackage = new TestPackage().Named("test.dll");
-        /// </example>
-        /// <remarks>
-        /// This is provided for use by engine extensions that manipulate
-        /// the package structure as well as for internal use. For general
-        /// programmatic use of the engine, either of the constructors
-        /// will create a TestPackage in the form that the runner expects.
-        /// </remarks>
-        public TestPackage Named(string fileName)
-        {
-            FullName = Path.GetFullPath(fileName);
-            return this;
-        }
-
         /// <summary>
         /// Gets the list of SubPackages contained in this package
         /// </summary>
@@ -132,6 +109,19 @@ public void AddSubPackage(TestPackage subPackage)
                 subPackage.Settings[key] = Settings[key];
         }
 
+        /// <summary>
+        /// Add a subproject to the package, specifying its name. This is
+        /// the only way to add a named subpackage to the top-level package.
+        /// </summary>
+        /// <param name="packageName">The name of the subpackage to be added</param>
+        public TestPackage AddSubPackage(string packageName)
+        {
+            var subPackage = new TestPackage() { FullName = Path.GetFullPath(packageName) };
+            SubPackages.Add(subPackage);
+
+            return subPackage;
+        }
+
         /// <summary>
         /// Add a setting to a package and all of its subpackages.
         /// </summary>

src/NUnitEngine/nunit.engine.tests/Runners/MultipleTestProcessRunnerTests.cs

@@ -40,7 +40,7 @@ MultipleTestProcessRunner CreateRunner(int assemblyCount, int? maxAgents)
             // Currently, we can get away with null entries here
             var package = new TestPackage();
             for (int i = 1; i <= assemblyCount; i++)
-                package.AddSubPackage(new TestPackage().Named($"test{i}.dll"));
+                package.AddSubPackage($"test{i}.dll");
 
             if (maxAgents != null)
                 package.Settings[EnginePackageSettings.MaxAgents] = maxAgents;

src/NUnitEngine/nunit.engine.tests/Services/DomainManagerTests.cs

@@ -13,7 +13,7 @@ public class DomainManagerTests
         private DomainManager _domainManager;
         // We use a named subpackage because that's what is normally
         // used by the Domain Manager
-        private TestPackage _package = new TestPackage().Named(MockAssembly.AssemblyPath);
+        private TestPackage _package = new TestPackage(MockAssembly.AssemblyPath).SubPackages[0];
 
         [SetUp]
         public void CreateDomainManager()

src/NUnitEngine/nunit.engine.tests/Services/Fakes/FakeProjectService.cs

@@ -27,7 +27,7 @@ void IProjectService.ExpandProjectPackage(TestPackage package)
             if (_projects.ContainsKey(package.Name))
             {
                 foreach (string assembly in _projects[package.Name])
-                    package.AddSubPackage(new TestPackage().Named(assembly));
+                    package.AddSubPackage(assembly);
             }
         }