Fix: SettingsProperty constructor ignores serializeAs parameter if it is not SettingsSerializeAs.Binary

src/libraries/System.Configuration.ConfigurationManager/src/System/Configuration/SettingsProperty.cs

@@ -52,6 +52,10 @@ public SettingsProperty(
                     throw new NotSupportedException(Obsoletions.BinaryFormatterMessage);
                 }
             }
+            else
+            {
+                SerializeAs = serializeAs;
+            }
             Attributes = attributes;
             ThrowOnErrorDeserializing = throwOnErrorDeserializing;
             ThrowOnErrorSerializing = throwOnErrorSerializing;

src/libraries/System.Configuration.ConfigurationManager/tests/System.Configuration.ConfigurationManager.Tests.csproj

@@ -78,6 +78,7 @@
     <Compile Include="System\Configuration\SettingsManageabilityAttributeTests.cs" />
     <Compile Include="System\Configuration\SettingsPropertyIsReadOnlyExceptionTests.cs" />
     <Compile Include="System\Configuration\SettingsPropertyNotFoundExceptionTests.cs" />
+    <Compile Include="System\Configuration\SettingsPropertyTests.cs" />
     <Compile Include="System\Configuration\SettingsPropertyWrongTypeExceptionTests.cs" />
     <Compile Include="System\Configuration\SmokeTest.cs" />
     <Compile Include="System\Configuration\StringUtilTests.cs" />
@@ -93,7 +94,7 @@
     <Compile Include="System\Configuration\UrlPathTests.cs" />
     <Compile Include="System\Configuration\ValidatiorUtilsTests.cs" />
     <Compile Include="System\Diagnostics\DiagnosticsTestData.cs" Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'" />
-    <Compile Include="System\Diagnostics\TraceSourceConfigurationTests.cs"  Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'" />
+    <Compile Include="System\Diagnostics\TraceSourceConfigurationTests.cs" Condition="'$(TargetFrameworkIdentifier)' == '.NETCoreApp'" />
     <Compile Include="System\Drawing\Configuration\SystemDrawingSectionTests.cs" />
   </ItemGroup>
   <ItemGroup>

src/libraries/System.Configuration.ConfigurationManager/tests/System/Configuration/SettingsPropertyTests.cs

@@ -0,0 +1,53 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Configuration;
+using Xunit;
+
+namespace System.ConfigurationTests
+{
+    public class SettingsPropertyTests
+    {
+        [Fact]
+        public void SettingsProperty_WithNoArguments()
+        {
+            var settingsProperty = new SettingsProperty("TestName");
+            Assert.Equal("TestName", settingsProperty.Name);
+            Assert.False(settingsProperty.IsReadOnly);
+            Assert.Null(settingsProperty.DefaultValue);
+            Assert.Null(settingsProperty.PropertyType);
+            Assert.Equal(SettingsSerializeAs.String, settingsProperty.SerializeAs);
+            Assert.Null(settingsProperty.Provider);
+            Assert.NotNull(settingsProperty.Attributes);
+            Assert.False(settingsProperty.ThrowOnErrorDeserializing);
+            Assert.False(settingsProperty.ThrowOnErrorSerializing);
+        }
+
+        [Theory]
+        [InlineData(SettingsSerializeAs.String)]
+        [InlineData(SettingsSerializeAs.Xml)]
+        [InlineData(SettingsSerializeAs.ProviderSpecific)]
+        public void SettingsProperty_WithArguments(SettingsSerializeAs serializeAs)
+        {
+            var settingsProperty = new SettingsProperty(
+                "TestName",
+                typeof(string),
+                provider: null,
+                isReadOnly: true,
+                "TestDefaultValue",
+                serializeAs,
+                new SettingsAttributeDictionary(),
+                throwOnErrorDeserializing: true,
+                throwOnErrorSerializing: false);
+            Assert.Equal("TestName", settingsProperty.Name);
+            Assert.True(settingsProperty.IsReadOnly);
+            Assert.Equal("TestDefaultValue", settingsProperty.DefaultValue);
+            Assert.Equal(typeof(string), settingsProperty.PropertyType);
+            Assert.Equal(serializeAs, settingsProperty.SerializeAs);
+            Assert.Null(settingsProperty.Provider);
+            Assert.NotNull(settingsProperty.Attributes);
+            Assert.True(settingsProperty.ThrowOnErrorDeserializing);
+            Assert.False(settingsProperty.ThrowOnErrorSerializing);
+        }
+    }
+}