Update JsonWriter unit tests.

src/System.Text.Json/src/Resources/Strings.resx

@@ -324,4 +324,7 @@
   <data name="SerializerOptionsImmutable" xml:space="preserve">
     <value>Serializer options cannot be changed once serialization or deserialization has occurred.</value>
   </data>
+  <data name="StreamNotWritable" xml:space="preserve">
+    <value>Stream was not writable.</value>
+  </data>
 </root>

src/System.Text.Json/src/System/Text/Json/Writer/Utf8JsonWriter.cs

@@ -122,7 +122,12 @@ public Utf8JsonWriter(IBufferWriter<byte> bufferWriter, JsonWriterOptions option
         /// </exception>
         public Utf8JsonWriter(Stream utf8Json, JsonWriterOptions options = default)
         {
-            _stream = utf8Json ?? throw new ArgumentNullException(nameof(utf8Json));
+            if (utf8Json == null)
+                throw new ArgumentNullException(nameof(utf8Json));
+            if (!utf8Json.CanWrite)
+                throw new ArgumentException(SR.StreamNotWritable);
+
+            _stream = utf8Json;
             _arrayBufferWriter = new ArrayBufferWriter<byte>();
             _output = _arrayBufferWriter;
 
@@ -166,11 +171,16 @@ public void Reset()
         /// but now write to the passed in <see cref="Stream" /> as the new destination.
         /// </remarks>
         /// <exception cref="ArgumentNullException">
-        /// Thrown when the instance of <see cref="IBufferWriter{Byte}" /> that is passed in is null.
+        /// Thrown when the instance of <see cref="Stream" /> that is passed in is null.
         /// </exception>
         public void Reset(Stream utf8Json)
         {
-            _stream = utf8Json ?? throw new ArgumentNullException(nameof(utf8Json));
+            if (utf8Json == null)
+                throw new ArgumentNullException(nameof(utf8Json));
+            if (!utf8Json.CanWrite)
+                throw new ArgumentException(SR.StreamNotWritable);
+
+            _stream = utf8Json;
             if (_arrayBufferWriter == null)
             {
                 _arrayBufferWriter = new ArrayBufferWriter<byte>();
@@ -193,7 +203,7 @@ public void Reset(Stream utf8Json)
         /// but now write to the passed in <see cref="IBufferWriter{Byte}" /> as the new destination.
         /// </remarks>
         /// <exception cref="ArgumentNullException">
-        /// Thrown when the instance of <see cref="Stream" /> that is passed in is null.
+        /// Thrown when the instance of <see cref="IBufferWriter{Byte}" /> that is passed in is null.
         /// </exception>
         public void Reset(IBufferWriter<byte> bufferWriter)
         {
@@ -792,7 +802,7 @@ private void WriteEndIndented(byte token)
                 }
 
                 Debug.Assert(indent <= 2 * JsonConstants.MaxWriterDepth);
-                Debug.Assert(_tokenType != JsonTokenType.None);
+                Debug.Assert(Options.SkipValidation || _tokenType != JsonTokenType.None);
 
                 int maxRequired = indent + 3; // 1 end token, 1-2 bytes for new line
 

src/System.Text.Json/tests/FixedSizedBufferWriter.cs

@@ -26,6 +26,8 @@ public void Clear()
 
         public byte[] Formatted => _buffer.AsSpan(0, _count).ToArray();
 
+        public int FormattedCount => _count;
+
         public Memory<byte> GetMemory(int minimumLength = 0) => _buffer.AsMemory(_count);
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

src/System.Text.Json/tests/JsonElementWriteTests.cs

@@ -831,15 +831,14 @@ public static void WritePropertyOutsideObject(bool skipValidation)
             using (var doc = JsonDocument.Parse("[ null, false, true, \"hi\", 5, {}, [] ]", s_readerOptions))
             {
                 JsonElement root = doc.RootElement;
-                JsonWriterState state = new JsonWriterState(
-                    new JsonWriterOptions
-                    {
-                        SkipValidation = skipValidation,
-                    });
+                var options = new JsonWriterOptions
+                {
+                    SkipValidation = skipValidation,
+                };
 
                 const string CharLabel = "char";
                 byte[] byteUtf8 = Encoding.UTF8.GetBytes("byte");
-                Utf8JsonWriter writer = new Utf8JsonWriter(buffer, state);
+                var writer = new Utf8JsonWriter(buffer, options);
 
                 if (skipValidation)
                 {
@@ -874,11 +873,7 @@ public static void WritePropertyOutsideObject(bool skipValidation)
                             (ref Utf8JsonWriter w) => val.WriteAsProperty(byteUtf8, ref w));
                     }
 
-                    JsonTestHelper.AssertThrows<InvalidOperationException>(
-                        ref writer,
-                        (ref Utf8JsonWriter w) => w.Flush());
-
-                    writer.Flush(isFinalBlock: false);
+                    writer.Flush();
 
                     AssertContents("", buffer);
                 }
@@ -894,13 +889,12 @@ public static void WriteValueInsideObject(bool skipValidation)
             using (var doc = JsonDocument.Parse("[ null, false, true, \"hi\", 5, {}, [] ]", s_readerOptions))
             {
                 JsonElement root = doc.RootElement;
-                JsonWriterState state = new JsonWriterState(
-                    new JsonWriterOptions
-                    {
-                        SkipValidation = skipValidation,
-                    });
+                var options = new JsonWriterOptions
+                {
+                    SkipValidation = skipValidation,
+                };
 
-                Utf8JsonWriter writer = new Utf8JsonWriter(buffer, state);
+                var writer = new Utf8JsonWriter(buffer, options);
                 writer.WriteStartObject();
 
                 if (skipValidation)
@@ -941,13 +935,12 @@ private static void WriteSimpleValue(bool indented, string jsonIn, string jsonOu
             {
                 JsonElement target = doc.RootElement[0];
 
-                var state = new JsonWriterState(
-                    new JsonWriterOptions
-                    {
-                        Indented = indented,
-                    });
+                var options = new JsonWriterOptions
+                {
+                    Indented = indented,
+                };
 
-                var writer = new Utf8JsonWriter(buffer, state);
+                var writer = new Utf8JsonWriter(buffer, options);
 
                 target.WriteAsValue(ref writer);
                 writer.Flush();
@@ -967,13 +960,12 @@ private static void WriteComplexValue(
             {
                 JsonElement target = doc.RootElement[0];
 
-                var state = new JsonWriterState(
-                    new JsonWriterOptions
-                    {
-                        Indented = indented,
-                    });
+                var options = new JsonWriterOptions
+                {
+                    Indented = indented,
+                };
 
-                var writer = new Utf8JsonWriter(buffer, state);
+                var writer = new Utf8JsonWriter(buffer, options);
 
                 target.WriteAsValue(ref writer);
                 writer.Flush();
@@ -1023,13 +1015,12 @@ private static void WritePropertyValue(
             {
                 JsonElement target = doc.RootElement[0];
 
-                var state = new JsonWriterState(
-                    new JsonWriterOptions
-                    {
-                        Indented = indented,
-                    });
+                var options = new JsonWriterOptions
+                {
+                    Indented = indented,
+                };
 
-                var writer = new Utf8JsonWriter(buffer, state);
+                var writer = new Utf8JsonWriter(buffer, options);
 
                 writer.WriteStartObject();
                 target.WriteAsProperty(propertyName, ref writer);
@@ -1059,13 +1050,12 @@ private static void WritePropertyValue(
             {
                 JsonElement target = doc.RootElement[0];
 
-                var state = new JsonWriterState(
-                    new JsonWriterOptions
-                    {
-                        Indented = indented,
-                    });
+                var options = new JsonWriterOptions
+                {
+                    Indented = indented,
+                };
 
-                var writer = new Utf8JsonWriter(buffer, state);
+                var writer = new Utf8JsonWriter(buffer, options);
 
                 writer.WriteStartObject();
                 target.WriteAsProperty(propertyName, ref writer);

src/System.Text.Json/tests/JsonWriterOptionsTests.cs

@@ -0,0 +1,56 @@
+// 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.Text.Json.Tests
+{
+    public static partial class JsonWriterOptionsTests
+    {
+        [Fact]
+        public static void JsonWriterOptionsDefaultCtor()
+        {
+            JsonWriterOptions options = default;
+
+            var expectedOption = new JsonWriterOptions
+            {
+                Indented = false,
+                SkipValidation = false
+            };
+            Assert.Equal(expectedOption, options);
+        }
+
+        [Fact]
+        public static void JsonWriterOptionsCtor()
+        {
+            var options = new JsonWriterOptions();
+
+            var expectedOption = new JsonWriterOptions
+            {
+                Indented = false,
+                SkipValidation = false
+            };
+            Assert.Equal(expectedOption, options);
+        }
+
+        [Theory]
+        [InlineData(true, true)]
+        [InlineData(true, false)]
+        [InlineData(false, true)]
+        [InlineData(false, false)]
+        public static void JsonWriterOptions(bool indented, bool skipValidation)
+        {
+            var options = new JsonWriterOptions();
+            options.Indented = indented;
+            options.SkipValidation = skipValidation;
+
+            var expectedOption = new JsonWriterOptions
+            {
+                Indented = indented,
+                SkipValidation = skipValidation
+            };
+            Assert.Equal(expectedOption, options);
+        }
+    }
+}

src/System.Text.Json/tests/System.Text.Json.Tests.csproj

@@ -21,7 +21,7 @@
     <Compile Include="JsonNumberTestData.cs" />
     <Compile Include="JsonReaderStateAndOptionsTests.cs" />
     <Compile Include="JsonTestHelper.cs" />
-    <Compile Include="JsonWriterStateTests.cs" />
+    <Compile Include="JsonWriterOptionsTests.cs" />
     <Compile Include="ResizableArray.cs" />
     <Compile Include="Serialization\Array.ReadTests.cs" />
     <Compile Include="Serialization\Array.WriteTests.cs" />