Add more misc type converters tests (dotnet/corefx#36655)

*  Add more misc type converters tests

* PR feedback


Commit migrated from dotnet/corefx@e65153e

src/libraries/System.ComponentModel.TypeConverter/src/System/ComponentModel/CharConverter.cs

@@ -7,8 +7,8 @@
 namespace System.ComponentModel
 {
     /// <summary>
-    /// Provides a type converter to convert Unicode character objects
-    /// to and from various other representations.
+    /// Provides a type converter to convert Unicode character objects to and from various
+    /// other representations.
     /// </summary>
     public class CharConverter : TypeConverter
     {
@@ -26,11 +26,11 @@ public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceT
         /// </summary>
         public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
         {
-            if (destinationType == typeof(string) && value is char)
+            if (destinationType == typeof(string) && value is char charValue)
             {
-                if ((char)value == (char)0)
+                if (charValue == '\0')
                 {
-                    return "";
+                    return string.Empty;
                 }
             }
 
@@ -55,6 +55,7 @@ public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo c
                     {
                         throw new FormatException(SR.Format(SR.ConvertInvalidPrimitive, text, nameof(Char)));
                     }
+
                     return text[0];
                 }
 

src/libraries/System.ComponentModel.TypeConverter/src/System/ComponentModel/CollectionConverter.cs

@@ -8,7 +8,8 @@
 namespace System.ComponentModel
 {
     /// <summary>
-    /// Provides a type converter to convert collection objects to and from various other representations.
+    /// Provides a type converter to convert collection objects to and from various other
+    /// representations.
     /// </summary>
     public class CollectionConverter : TypeConverter
     {
@@ -17,11 +18,6 @@ public class CollectionConverter : TypeConverter
         /// </summary>
         public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
         {
-            if (destinationType == null)
-            {
-                throw new ArgumentNullException(nameof(destinationType));
-            }
-
             if (destinationType == typeof(string) && value is ICollection)
             {
                 return SR.Collection;
@@ -31,17 +27,12 @@ public override object ConvertTo(ITypeDescriptorContext context, CultureInfo cul
         }
 
         /// <summary>
-        /// Gets a collection of properties for the type of array specified by the value parameter using
-        /// the specified context and attributes.
+        /// Gets a collection of properties for the type of array specified by the value
+        /// parameter using the specified context and attributes.
         /// </summary>
         public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
         {
             return new PropertyDescriptorCollection(null);
         }
-
-        /// <summary>
-        /// Gets a value indicating whether this object supports properties.
-        /// </summary>
-        public override bool GetPropertiesSupported(ITypeDescriptorContext context) => false;
     }
 }

src/libraries/System.ComponentModel.TypeConverter/tests/BooleanConverterTests.cs

@@ -2,42 +2,49 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Design.Serialization;
 using System.Globalization;
+using System.Linq;
 using Xunit;
 
 namespace System.ComponentModel.Tests
 {
-    public class BooleanConverterTests : ConverterTestBase
+    public class BooleanConverterTests : TypeConverterTestBase
     {
-        private static BooleanConverter s_converter = new BooleanConverter();
+        public override TypeConverter Converter => new BooleanConverter();
 
-        [Fact]
-        public static void CanConvertFrom_WithContext()
+        public override bool StandardValuesSupported => true;
+        public override bool StandardValuesExclusive => true;
+
+        public override IEnumerable<ConvertTest> ConvertToTestData()
         {
-            CanConvertFrom_WithContext(new object[2, 2]
-                {
-                    { typeof(string), true },
-                    { typeof(int), false }
-                },
-                BooleanConverterTests.s_converter);
+            yield return ConvertTest.Valid(true, Boolean.TrueString);
+            yield return ConvertTest.Valid(1, "1");
+
+            yield return ConvertTest.CantConvertTo(true, typeof(bool));
+            yield return ConvertTest.CantConvertTo(true, typeof(InstanceDescriptor));
+            yield return ConvertTest.CantConvertTo(true, typeof(object));
         }
 
-        [Fact]
-        public static void ConvertFrom_WithContext()
+        public override IEnumerable<ConvertTest> ConvertFromTestData()
         {
-            ConvertFrom_WithContext(new object[2, 3]
-                {
-                    { "false  ", false, null },
-                    { "true", true, CultureInfo.InvariantCulture }
-                },
-                BooleanConverterTests.s_converter);
+            yield return ConvertTest.Valid("false  ", false);
+            yield return ConvertTest.Valid("true", true, CultureInfo.InvariantCulture);
+
+            yield return ConvertTest.Throws<FormatException>("1");
+
+            yield return ConvertTest.CantConvertFrom(1);
+            yield return ConvertTest.CantConvertFrom(null);
         }
 
         [Fact]
-        public static void ConvertFrom_WithContext_Negative()
+        public void StandardValues_Get_ReturnsExpected()
         {
-            Assert.Throws<FormatException>(
-                () => BooleanConverterTests.s_converter.ConvertFrom(TypeConverterTests.s_context, null, "1"));
+            ICollection values = Converter.GetStandardValues();
+            Assert.Same(values, Converter.GetStandardValues());
+            Assert.Equal(new object[] { true, false }, values.Cast<object>());
         }
     }
 }

src/libraries/System.ComponentModel.TypeConverter/tests/CharConverterTests.cs

@@ -2,58 +2,40 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Design.Serialization;
 using System.Globalization;
+using System.Linq;
 using Xunit;
 
 namespace System.ComponentModel.Tests
 {
-    public class CharConverterTests : ConverterTestBase
+    public class CharConverterTests : TypeConverterTestBase
     {
-        private static TypeConverter s_converter = new CharConverter();
+        public override TypeConverter Converter => new CharConverter();
 
-        [Fact]
-        public static void CanConvertFrom_WithContext()
+        public override IEnumerable<ConvertTest> ConvertToTestData()
         {
-            CanConvertFrom_WithContext(new object[2, 2]
-                {
-                    { typeof(string), true },
-                    { typeof(int), false }
-                },
-                CharConverterTests.s_converter);
-        }
+            yield return ConvertTest.Valid('a', "a");
+            yield return ConvertTest.Valid('\u20AC', "\u20AC", CultureInfo.InvariantCulture);
+            yield return ConvertTest.Valid('\0', string.Empty);
 
-        [Fact]
-        public static void ConvertTo_WithContext()
-        {
-            ConvertTo_WithContext(new object[3, 3]
-                {
-                    {'a', "a", null},
-                    {'\0', "", null},
-                    {'\u20AC', "\u20AC", CultureInfo.InvariantCulture}
-                },
-                CharConverterTests.s_converter);
+            yield return ConvertTest.CantConvertTo('a', typeof(char));
+            yield return ConvertTest.CantConvertTo('a', typeof(InstanceDescriptor));
+            yield return ConvertTest.CantConvertTo('a', typeof(object));
         }
 
-        [Fact]
-        public static void ConvertFrom_WithContext()
+        public override IEnumerable<ConvertTest> ConvertFromTestData()
         {
-            ConvertFrom_WithContext(new object[3, 3]
-                {
-                    { " a  ", 'a', CultureInfo.InvariantCulture },
-                    { "    ", '\0', null},
-                    { "", '\0', null }
-                },
-               CharConverterTests.s_converter);
-        }
+            yield return ConvertTest.Valid("  a  ", 'a');
+            yield return ConvertTest.Valid("    ", '\0');
+            yield return ConvertTest.Valid("", '\0');
 
-        [Fact]
-        public static void ConvertFrom_WithContext_Negative()
-        {
-            Assert.Throws<FormatException>(
-                () => CharConverterTests.s_converter.ConvertFrom(TypeConverterTests.s_context, null, "aaa"));
+            yield return ConvertTest.Throws<FormatException>("aa");
 
-            Assert.Throws<NotSupportedException>(
-                () => CharConverterTests.s_converter.ConvertFrom(TypeConverterTests.s_context, null, null));
+            yield return ConvertTest.CantConvertFrom(1);
+            yield return ConvertTest.CantConvertFrom(null);
         }
     }
-}
+}

src/libraries/System.ComponentModel.TypeConverter/tests/CollectionConverterTests.cs

@@ -2,29 +2,59 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Globalization;
-using Microsoft.DotNet.RemoteExecutor;
+using System.Collections;
+using System.Collections.Generic;
+using System.ComponentModel.Design.Serialization;
 using Xunit;
 
 namespace System.ComponentModel.Tests
 {
-    public class CollectionConverterTests : ConverterTestBase
+    public class CollectionConverterTests : TypeConverterTestBase
     {
-        private static TypeConverter s_converter = new CollectionConverter();
+        public override TypeConverter Converter => new CollectionConverter();
 
-        [Fact]
-        public static void ConvertTo_WithContext()
+        public override IEnumerable<ConvertTest> ConvertToTestData()
         {
-            RemoteExecutor.Invoke(() =>
-            {
-                CultureInfo.CurrentUICulture = CultureInfo.InvariantCulture;
-
-                ConvertTo_WithContext(new object[1, 3]
-                    {
-                        { new Collection1(), "(Collection)", null }
-                    },
-                    CollectionConverterTests.s_converter);
-            }).Dispose();
+            yield return ConvertTest.Valid(new CustomCollection(), "(Collection)").WithInvariantRemoteInvokeCulture();
+            yield return ConvertTest.Valid(1, "1");
+
+            yield return ConvertTest.CantConvertTo(new CustomCollection(), typeof(CustomCollection));
+            yield return ConvertTest.CantConvertTo(new CustomCollection(), typeof(InstanceDescriptor));
+            yield return ConvertTest.CantConvertTo(new CustomCollection(), typeof(object));
+        }
+
+        public override IEnumerable<ConvertTest> ConvertFromTestData()
+        {
+            yield return ConvertTest.CantConvertFrom(new CustomCollection());
+        }
+
+        public static IEnumerable<object[]> GetProperties_TestData()
+        {
+            yield return new object[] { null };
+            yield return new object[] { new CustomCollection() };
+        }
+
+        [Theory]
+        [MemberData(nameof(GetProperties_TestData))]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework, "Returns null in .NET Framework")]
+        public void GetProperties_Invoke_ReturnsEmpty(object value)
+        {
+            PropertyDescriptorCollection properties = Converter.GetProperties(value);
+            Assert.Empty(properties);
+        }
+
+        [Serializable]
+        public class CustomCollection : ICollection
+        {
+            public void CopyTo(Array array, int index) => throw new NotImplementedException();
+
+            public int Count => throw new NotImplementedException();
+
+            public bool IsSynchronized => throw new NotImplementedException();
+
+            public object SyncRoot => throw new NotImplementedException();
+
+            public IEnumerator GetEnumerator() => throw new NotImplementedException();
         }
     }
 }

src/libraries/System.ComponentModel.TypeConverter/tests/Int16ConverterTests.cs

@@ -32,7 +32,7 @@ public override IEnumerable<ConvertTest> ConvertFromTestData()
             yield return ConvertTest.Throws<ArgumentException, Exception>("32768");
             yield return ConvertTest.Throws<ArgumentException, Exception>("-32769");
 
-            yield return ConvertTest.CantConvert(new object());
+            yield return ConvertTest.CantConvertFrom(new object());
         }
     }
 }

src/libraries/System.ComponentModel.TypeConverter/tests/SampleClasses.cs

@@ -60,35 +60,6 @@ public string ToString(string format, IFormatProvider formatProvider)
         public const string Token = "Formatted class.";
     }
 
-    [Serializable]
-    public class Collection1 : ICollection
-    {
-        public void CopyTo(Array array, int index)
-        {
-            throw new NotImplementedException();
-        }
-
-        public int Count
-        {
-            get { throw new NotImplementedException(); }
-        }
-
-        public bool IsSynchronized
-        {
-            get { throw new NotImplementedException(); }
-        }
-
-        public object SyncRoot
-        {
-            get { throw new NotImplementedException(); }
-        }
-
-        public IEnumerator GetEnumerator()
-        {
-            throw new NotImplementedException();
-        }
-    }
-
     public class MyTypeListConverter : TypeListConverter
     {
         public MyTypeListConverter(Type[] types)

src/libraries/System.ComponentModel.TypeConverter/tests/TypeConverterTestBase.cs

@@ -196,7 +196,7 @@ public static ConvertTest Throws<TNetCoreException, TNetFrameworkException>(obje
                 };
             }
 
-            public static ConvertTest CantConvert(object source, Type destinationType = null, CultureInfo culture = null)
+            public static ConvertTest CantConvertTo(object source, Type destinationType = null, CultureInfo culture = null)
             {
                 return new ConvertTest
                 {
@@ -209,6 +209,18 @@ public static ConvertTest CantConvert(object source, Type destinationType = null
                 };
             }
 
+            public static ConvertTest CantConvertFrom(object source,  CultureInfo culture = null)
+            {
+                return new ConvertTest
+                {
+                    Source = source,
+                    Culture = culture,
+                    NetCoreExceptionType = typeof(NotSupportedException),
+                    NetFrameworkExceptionType = typeof(NotSupportedException),
+                    CanConvert = false
+                };
+            }
+
             public ConvertTest WithContext(ITypeDescriptorContext context)
             {
                 Context = context;