Add ToolboxItem tests and fix bugs

src/System.Windows.Forms.Design/src/System/Drawing/Design/ToolboxItem.cs

@@ -101,7 +101,7 @@ public AssemblyName[] DependentAssemblies
             }
             set
             {
-                Properties["DependentAssemblies"] = value.Clone();
+                Properties["DependentAssemblies"] = value?.Clone();
             }
         }
 
@@ -277,23 +277,15 @@ public string TypeName
         }
 
         /// <summary>
-        /// Gets the version for this toolboxitem.  It defaults to AssemblyName.Version unless
-        /// overridden in a derived toolboxitem.  This can be overridden to return an empty string
-        /// to suppress its display in the toolbox tooltip.
+        /// Gets the version for this toolboxitem. It defaults to AssemblyName.Version unless
+        /// overridden in a derived toolboxitem. This can be overridden to
+        /// return an empty string to suppress its display in the toolbox tooltip.
         /// </summary>
         public virtual string Version
         {
-            get
-            {
-                if (AssemblyName != null)
-                {
-                    return AssemblyName.Version.ToString();
-                }
-                return string.Empty;
-            }
+            get => AssemblyName?.Version?.ToString() ?? string.Empty;
         }
 
-
         /// <summary>
         /// Occurs when components are created.
         /// </summary>
@@ -408,7 +400,7 @@ protected virtual IComponent[] CreateComponentsCore(IDesignerHost host, IDiction
         {
             IComponent[] components = CreateComponentsCore(host);
 
-            if (host != null)
+            if (host != null && components != null)
             {
                 for (int i = 0; i < components.Length; i++)
                 {
@@ -527,10 +519,9 @@ private static bool AreAssemblyNamesEqual(AssemblyName name1, AssemblyName name2
 
         public override int GetHashCode()
         {
-            string typeName = TypeName;
-            int hash = (typeName != null) ? typeName.GetHashCode() : 0;
-
-            return unchecked(hash ^ DisplayName.GetHashCode());
+            int typeHash = TypeName?.GetHashCode() ?? 0;
+            int displayHash = DisplayName?.GetHashCode() ?? 0;
+            return unchecked(typeHash ^ displayHash);
         }
 
         /// <summary>
@@ -542,8 +533,8 @@ protected virtual object FilterPropertyValue(string propertyName, object value)
             switch (propertyName)
             {
                 case "AssemblyName":
-                    if (value != null)
-                        value = ((AssemblyName)value).Clone();
+                    if (value is AssemblyName valueName)
+                        value = valueName.Clone();
 
                     break;
 
@@ -598,7 +589,7 @@ protected virtual Type GetType(IDesignerHost host, AssemblyName assemblyName, st
 
             if (host != null)
             {
-                ts = (ITypeResolutionService)host.GetService(typeof(ITypeResolutionService));
+                ts = host.GetService(typeof(ITypeResolutionService)) as ITypeResolutionService;
             }
 
             if (ts != null)
@@ -664,7 +655,7 @@ protected virtual Type GetType(IDesignerHost host, AssemblyName assemblyName, st
                         {
                         }
 
-                        if (a == null && assemblyName.CodeBase != null && assemblyName.CodeBase.Length > 0)
+                        if (a == null && !string.IsNullOrEmpty(assemblyName.CodeBase))
                         {
                             try
                             {
@@ -804,7 +795,8 @@ public virtual void Initialize(Type type)
 
         private AssemblyName GetNonRetargetedAssemblyName(Type type, AssemblyName policiedAssemblyName)
         {
-            if (type == null || policiedAssemblyName == null)
+            Debug.Assert(type != null);
+            if (policiedAssemblyName == null)
                 return null;
 
             //if looking for myself, just return it. (not a reference)	
@@ -833,17 +825,17 @@ private AssemblyName GetNonRetargetedAssemblyName(Type type, AssemblyName polici
             // in assemblyname.	
             foreach (AssemblyName name in type.Assembly.GetReferencedAssemblies())
             {
-                Assembly a = null;
-
                 try
                 {
-                    a = Assembly.Load(name);
-                    if (a != null && a.FullName == policiedAssemblyName.FullName)
+                    Assembly a = Assembly.Load(name);
+                    if (a.FullName == policiedAssemblyName.FullName)
+                    {
                         return name;
+                    }
                 }
                 catch
                 {
-                    //ignore all exceptions and just fall through if it fails (it shouldn't, but who knows).	
+                    // Ignore all exceptions and just fall through if it fails (it shouldn't, but who knows).	
                 }
             }
 
@@ -900,10 +892,7 @@ protected virtual void OnComponentsCreating(ToolboxComponentsCreatingEventArgs a
             _componentsCreatingEvent?.Invoke(this, args);
         }
 
-        public override string ToString()
-        {
-            return DisplayName;
-        }
+        public override string ToString() => DisplayName ?? string.Empty;
 
         /// <summary>
         /// Called as a helper to ValidatePropertyValue to validate that an object
@@ -992,6 +981,10 @@ protected virtual object ValidatePropertyValue(string propertyName, object value
                     value = filter;
                     break;
 
+                case "DependentAssemblies":
+                    ValidatePropertyType(propertyName, value, typeof(AssemblyName[]), true);
+                    break;
+
                 case "IsTransient":
                     ValidatePropertyType(propertyName, value, typeof(bool), false);
                     break;
@@ -1002,7 +995,6 @@ protected virtual object ValidatePropertyValue(string propertyName, object value
         [SuppressMessage("Microsoft.Usage", "CA2240:ImplementISerializableCorrectly")]
         void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
         {
-            //IntSecurity.UnmanagedCode.Demand();
             Serialize(info, context);
         }
 

src/System.Windows.Forms.Design/tests/UnitTests/System.Windows.Forms.Design.Tests.csproj

@@ -14,8 +14,20 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\System.Windows.Forms.Design.csproj" />
+    <Compile Include="..\..\..\Common\tests\CommonMemberDataAttribute.cs" Link="Common\CommonMemberDataAttribute.cs" />
     <Compile Include="..\..\..\Common\tests\CommonTestHelper.cs" Link="Common\CommonTestHelper.cs" />
     <ProjectReference Include="..\..\..\Common\tests\InternalUtilitiesForTests\InternalUtilitiesForTests.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <EmbeddedResource Include="Resources\16x16.bmp">
+      <LogicalName>System.Drawing.Design.Tests.16x16.bmp</LogicalName>
+    </EmbeddedResource>
+    <EmbeddedResource Include="Resources\24x16.bmp">
+      <LogicalName>System.Drawing.Design.Tests.24x16.bmp</LogicalName>
+    </EmbeddedResource>
+    <EmbeddedResource Include="Resources\16x24.bmp">
+      <LogicalName>System.Drawing.Design.Tests.16x24.bmp</LogicalName>
+    </EmbeddedResource>
+  </ItemGroup>
 </Project>

src/System.Windows.Forms.Design/tests/UnitTests/System/Drawing/Design/ToolboxItemCollectionTests.cs

@@ -0,0 +1,75 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Xunit;
+
+namespace System.Drawing.Design.Tests
+{
+    public class ToolboxItemCollectionTests
+    {
+        [Fact]
+        public void ToolboxItemCollection_Ctor_ToolboxItemArray()
+        {
+            var item = new ToolboxItem();
+            var collection = new ToolboxItemCollection(new ToolboxItem[] { item });
+            Assert.Same(item, Assert.Single(collection));
+            Assert.Same(item, collection[0]);
+            Assert.True(collection.Contains(item));
+            Assert.Equal(0, collection.IndexOf(item));
+        }
+
+        [Fact]
+        public void ToolboxItemCollection_Ctor_NullToolboxItemArray_ThrowsArgumentNullException()
+        {
+            Assert.Throws<ArgumentNullException>("c", () => new ToolboxItemCollection((ToolboxItem[])null));
+        }
+
+        [Fact]
+        public void ToolboxItemCollection_Ctor_ToolboxItemCollection()
+        {
+            var item = new ToolboxItem();
+            var value = new ToolboxItemCollection(new ToolboxItem[] { item });
+            var collection = new ToolboxItemCollection(value);
+            Assert.Same(item, Assert.Single(collection));
+            Assert.Same(item, collection[0]);
+            Assert.True(collection.Contains(item));
+            Assert.Equal(0, collection.IndexOf(item));
+        }
+
+        [Fact]
+        public void ToolboxItemCollection_Ctor_NullToolboxItemCollection_ThrowsArgumentNullException()
+        {
+            Assert.Throws<ArgumentNullException>("c", () => new ToolboxItemCollection((ToolboxItemCollection)null));
+        }
+
+        [Fact]
+        public void ToolboxItemCollection_Contains_NoSuchValue_ReturnsFalse()
+        {
+            var item = new ToolboxItem();
+            var collection = new ToolboxItemCollection(new ToolboxItem[] { item });
+            Assert.False(collection.Contains(new ToolboxItem { DisplayName = "Other" }));
+            Assert.False(collection.Contains(null));
+        }
+
+        [Fact]
+        public void ToolboxItemCollection_IndexOf_NoSuchValue_ReturnsNegativeOne()
+        {
+            var item = new ToolboxItem();
+            var collection = new ToolboxItemCollection(new ToolboxItem[] { item });
+            Assert.Equal(-1, collection.IndexOf(new ToolboxItem { DisplayName = "Other" }));
+            Assert.Equal(-1, collection.IndexOf(null));
+        }
+
+        [Fact]
+        public void ToolboxItemCollection_CopyTo_Invoke_Success()
+        {
+            var item = new ToolboxItem();
+            var collection = new ToolboxItemCollection(new ToolboxItem[] { item });
+
+            var array = new ToolboxItem[3];
+            collection.CopyTo(array, 1);
+            Assert.Equal(new ToolboxItem[] { null, item, null }, array);
+        }
+    }
+}