Remove code smells

Author: MaggieKimani1

src/Microsoft.OpenApi.Readers/OpenApiYamlReader.cs

@@ -77,7 +77,7 @@ static JsonNode LoadJsonNodesFromYamlDocument(TextReader input)
         {
             var yamlStream = new YamlStream();
             yamlStream.Load(input);
-            var yamlDocument = yamlStream.Documents.First();
+            var yamlDocument = yamlStream.Documents[0];
             return yamlDocument.ToJsonNode();
         }
 

src/Microsoft.OpenApi/Models/OpenApiTag.cs

@@ -55,10 +55,10 @@ public OpenApiTag(OpenApiTag tag)
         {
             Name = tag?.Name ?? Name;
             Description = tag?.Description ?? Description;
-            ExternalDocs = tag?.ExternalDocs != null ? new(tag?.ExternalDocs) : null;
+            ExternalDocs = tag?.ExternalDocs != null ? new(tag.ExternalDocs) : null;
             Extensions = tag?.Extensions != null ? new Dictionary<string, IOpenApiExtension>(tag.Extensions) : null;
             UnresolvedReference = tag?.UnresolvedReference ?? UnresolvedReference;
-            Reference = tag?.Reference != null ? new(tag?.Reference) : null;
+            Reference = tag?.Reference != null ? new(tag.Reference) : null;
         }
 
         /// <summary>

test/Microsoft.OpenApi.Tests/Models/OpenApiTagTests.cs

@@ -18,9 +18,9 @@ namespace Microsoft.OpenApi.Tests.Models
     [Collection("DefaultSettings")]
     public class OpenApiTagTests
     {
-        public static OpenApiTag BasicTag = new();
+        public static readonly OpenApiTag BasicTag = new();
 
-        public static OpenApiTag AdvancedTag = new()
+        public static readonly OpenApiTag AdvancedTag = new()
         {
             Name = "pet",
             Description = "Pets operations",
@@ -104,40 +104,6 @@ public void SerializeBasicTagAsV2YamlWithoutReferenceWorks()
             actual.Should().Be(expected);
         }
 
-        [Theory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task SerializeAdvancedTagAsV3JsonWithoutReferenceWorksAsync(bool produceTerseOutput)
-        {
-            // Arrange
-            var outputStringWriter = new StringWriter(CultureInfo.InvariantCulture);
-            var writer = new OpenApiJsonWriter(outputStringWriter, new() { Terse = produceTerseOutput });
-
-            // Act
-            AdvancedTag.SerializeAsV3(writer);
-            writer.Flush();
-
-            // Assert
-            await Verifier.Verify(outputStringWriter).UseParameters(produceTerseOutput);
-        }
-
-        [Theory]
-        [InlineData(true)]
-        [InlineData(false)]
-        public async Task SerializeAdvancedTagAsV2JsonWithoutReferenceWorksAsync(bool produceTerseOutput)
-        {
-            // Arrange
-            var outputStringWriter = new StringWriter(CultureInfo.InvariantCulture);
-            var writer = new OpenApiJsonWriter(outputStringWriter, new() { Terse = produceTerseOutput });
-
-            // Act
-            AdvancedTag.SerializeAsV2(writer);
-            writer.Flush();
-
-            // Assert
-            await Verifier.Verify(outputStringWriter).UseParameters(produceTerseOutput);
-        }
-
         [Fact]
         public void SerializeAdvancedTagAsV3YamlWithoutReferenceWorks()
         {