[browser][wasm][tests] Add tests for DataView (dotnet#38498)

src/libraries/System.Runtime.InteropServices.JavaScript/tests/System.Runtime.InteropServices.JavaScript.Tests.csproj

@@ -9,5 +9,6 @@
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetsBrowser)' == 'true'">
     <Compile Include="System\Runtime\InteropServices\JavaScript\JavaScriptTests.cs" />
+    <Compile Include="System\Runtime\InteropServices\JavaScript\DataViewTests.cs" />
   </ItemGroup>
 </Project>

src/libraries/System.Runtime.InteropServices.JavaScript/tests/System/Runtime/InteropServices/JavaScript/DataViewTests.cs

@@ -0,0 +1,136 @@
+// 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 System.Collections.Generic;
+using System.Runtime.InteropServices.JavaScript;
+using Xunit;
+
+namespace System.Runtime.InteropServices.JavaScript.Tests
+{
+    public static class DataViewTests
+    {
+        [Fact]
+        public static void DataViewConstructor()
+        {
+            // create an ArrayBuffer with a size in bytes
+            var buffer = new ArrayBuffer(16);
+
+            // Create a couple of views
+            var view1 = new DataView(buffer);
+            var view2 = new DataView(buffer, 12, 4); //from byte 12 for the next 4 bytes
+            view1.SetInt8(12, 42); // put 42 in slot 12 
+
+            Assert.Equal(42, view2.GetInt8(0));
+        }
+
+        public static IEnumerable<object[]> ArrayBuffer_Test_Data()
+        {
+            yield return new object[] { new ArrayBuffer(12) };
+        }
+
+        [Theory]
+        [MemberData(nameof(ArrayBuffer_Test_Data))]
+        public static void DataViewArrayBuffer(ArrayBuffer buffer)
+        {
+            var x = new DataView(buffer);
+            Assert.True(buffer == x.Buffer);
+        }
+
+        [Theory]
+        [MemberData(nameof(ArrayBuffer_Test_Data))]
+        public static void DataViewByteLength(ArrayBuffer buffer)
+        {
+            var x = new DataView(buffer, 4, 2);
+            Assert.Equal(2, x.ByteLength);
+        }
+
+        [Theory]
+        [MemberData(nameof(ArrayBuffer_Test_Data))]
+        public static void DataViewByteOffset(ArrayBuffer buffer)
+        {
+            var x = new DataView(buffer, 4, 2);
+            Assert.Equal(4, x.ByteOffset);
+        }
+
+        public static IEnumerable<object[]> DataView_Test_Data()
+        {
+            yield return new object[] { new DataView(new ArrayBuffer(12), 0) };
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+
+        public static void DataViewGetFloat32(DataView view)
+        {
+            view.SetFloat32(1, (float)Math.PI);
+            Assert.Equal((float)Math.Round(Math.PI, 5), (float)Math.Round(view.GetFloat32(1), 5));
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetFloat64(DataView view)
+        {
+            view.SetFloat64(1, (float)Math.PI);
+            Assert.Equal(Math.Round(Math.PI, 5), Math.Round(view.GetFloat64(1), 5));
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetInt16(DataView view)
+        {
+            view.SetInt16(1, 1234);
+            Assert.Equal(1234, view.GetInt16(1));
+
+            view.SetInt16(1, -1234);
+            Assert.Equal(-1234, view.GetInt16(1));
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetInt32(DataView view)
+        {
+            view.SetInt32(1, 1234);
+            Assert.Equal(1234, view.GetInt32(1));
+
+            view.SetInt32(1, -1234);
+            Assert.Equal(-1234, view.GetInt32(1));
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetInt8(DataView view)
+        {
+            view.SetInt8(1, 123);
+            Assert.Equal(123, view.GetInt8(1));
+
+            view.SetInt8(1, -123);
+            Assert.Equal(-123, view.GetInt8(1));
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetUint16(DataView view)
+        {
+            view.SetUint16(1, 1234);
+            Assert.Equal(1234, view.GetUint16(1));
+
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetUint32(DataView view)
+        {
+            view.SetUint32(1, 1234);
+            Assert.Equal(1234u, view.GetUint32(1));
+        }
+
+        [Theory]
+        [MemberData(nameof(DataView_Test_Data))]
+        public static void DataViewGetUint8(DataView view)
+        {
+            view.SetUint8(1, 123);
+            Assert.Equal(123u, view.GetUint8(1));
+        }
+    }
+}