Selecting XML nodes with XPath: retarget net10.0, drop null-forgiving operators, add LINQ to XML XPath method and tests (#2199)

Author: vladimir-pecanac-main

xml-csharp/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpath/Program.cs

@@ -1,18 +1,25 @@
 using SelectingXmlNodesWithXpath;
 using System.Xml;
+using System.Xml.Linq;
+
+var path = Path.Combine(AppContext.BaseDirectory, "BooksCatalog.xml");
 
 var doc = new XmlDocument();
-doc.Load("BooksCatalog.xml");
+doc.Load(path);
 var root = doc.DocumentElement!;
 
 Console.WriteLine("Selected book:");
 var singleResult = XmlNodesSelector.SelectSingleBook(root);
-Console.WriteLine(singleResult);
+Console.WriteLine(singleResult ?? "No book matched the query.");
 
 Console.WriteLine("\nSelected books:");
 var results = XmlNodesSelector.SelectBooks(root);
 results.ForEach(Console.WriteLine);
 
 Console.WriteLine("\nSelected books:");
 var resultsFromNamespaces = XmlNodesSelector.SelectBooksUsingNamespaces(doc);
-resultsFromNamespaces.ForEach(Console.WriteLine);
+resultsFromNamespaces.ForEach(Console.WriteLine);
+
+Console.WriteLine("\nSelected books with LINQ to XML:");
+var linqResults = XmlNodesSelector.SelectBooksWithLinqToXml(XDocument.Load(path));
+linqResults.ForEach(Console.WriteLine);

xml-csharp/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpath.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>

xml-csharp/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpath/XmlNodesSelector.cs

@@ -1,5 +1,6 @@
 using System.Xml;
 using System.Xml.Linq;
+using System.Xml.XPath;
 
 namespace SelectingXmlNodesWithXpath;
 
@@ -10,18 +11,23 @@ public static string FormatXml(string unformattedXml)
         return XElement.Parse(unformattedXml).ToString();
     }
 
-    public static string SelectSingleBook(XmlNode root)
+    public static string? SelectSingleBook(XmlNode root)
     {
         var node = root.SelectSingleNode("//catalog/book[position()=2]");
-        
-        return FormatXml(node!.OuterXml);
+
+        return node is null ? null : FormatXml(node.OuterXml);
     }
 
     public static List<string> SelectBooks(XmlNode root)
     {
         var nodes = root.SelectNodes("//catalog/book[price<50.00]");
 
-        return nodes!
+        if (nodes is null)
+        {
+            return [];
+        }
+
+        return nodes
             .Cast<XmlNode>()
             .Select(x => FormatXml(x.OuterXml))
             .ToList();
@@ -34,9 +40,22 @@ public static List<string> SelectBooksUsingNamespaces(XmlDocument doc)
 
         var nodes = doc.SelectNodes("descendant::ex:book", nsmgr);
 
-        return nodes!
+        if (nodes is null)
+        {
+            return [];
+        }
+
+        return nodes
             .Cast<XmlNode>()
             .Select(x => FormatXml(x.OuterXml))
             .ToList();
     }
+
+    public static List<string> SelectBooksWithLinqToXml(XDocument doc)
+    {
+        return doc
+            .XPathSelectElements("//catalog/book[price<50.00]")
+            .Select(x => x.ToString())
+            .ToList();
+    }
 }

xml-csharp/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpathTests/GlobalUsings.cs

@@ -1,3 +1,4 @@
 global using SelectingXmlNodesWithXpath;
 global using System.Xml;
-global using Xunit;
+global using Xunit;
+global using System.Xml.Linq;

xml-csharp/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpathTests/Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 
@@ -16,13 +16,13 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.6.0" />
-    <PackageReference Include="xunit" Version="2.4.2" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.10.0" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="4.0.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="3.2.0">
+    <PackageReference Include="coverlet.collector" Version="10.0.1">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>

xml-csharp/SelectingXmlNodesWithXpath/SelectingXmlNodesWithXpathTests/XmlNodesSelectorTest.cs

@@ -64,18 +64,20 @@ public void GivenAnXmlFile_WhenSelectingASingleNode_ThenReturnsTheSecondPosition
     {
         var result = XmlNodesSelector.SelectSingleBook(_document.DocumentElement!);
 
-        Assert.Equal(result, _expectedResults["Book2"]);
+        Assert.Equal(result?.ReplaceLineEndings(), _expectedResults["Book2"].ReplaceLineEndings());
     }
 
     [Fact]
     public void GivenAnXmlFile_WhenSelectingNodes_ThenReturnBooksWithPriceLowerThan50()
     {
         var expected = _expectedResults
             .Where(pair => pair.Key is "Book1" or "Book3")
-            .Select(pair => pair.Value)
+            .Select(pair => pair.Value.ReplaceLineEndings())
             .ToList();
 
-        var result = XmlNodesSelector.SelectBooks(_document.DocumentElement!);
+        var result = XmlNodesSelector.SelectBooks(_document.DocumentElement!)
+            .Select(x => x.ReplaceLineEndings())
+            .ToList();
 
         Assert.Equal(result, expected);
     }
@@ -86,11 +88,53 @@ public void GivenAnXmlFile_WhenSelectingNodesUsingNamespaces_ThenReturnBookEleme
         var expected =
             _expectedResults
             .Where(pair => pair.Key is "Book4")
-            .Select(pair => pair.Value)
+            .Select(pair => pair.Value.ReplaceLineEndings())
             .ToList();
 
-        var result = XmlNodesSelector.SelectBooksUsingNamespaces(_document);
+        var result = XmlNodesSelector.SelectBooksUsingNamespaces(_document)
+            .Select(x => x.ReplaceLineEndings())
+            .ToList();
 
         Assert.Equal(result, expected);
     }
-}
+
+    [Fact]
+    public void GivenAnXmlFile_WhenSelectSingleNodeMatchesNothing_ThenReturnsNull()
+    {
+        var node = _document.DocumentElement!.SelectSingleNode("//catalog/book[price>1000]");
+
+        Assert.Null(node);
+    }
+
+    [Fact]
+    public void GivenAnXmlFile_WhenSelectNodesMatchesNothing_ThenReturnsAnEmptyList()
+    {
+        var nodes = _document.DocumentElement!.SelectNodes("//catalog/book[price>1000]");
+
+        Assert.NotNull(nodes);
+        Assert.Equal(0, nodes.Count);
+    }
+
+    [Fact]
+    public void GivenABookInADefaultNamespace_WhenQueryingWithAnUnprefixedName_ThenReturnsThreeOfTheFourBooks()
+    {
+        var nodes = _document.DocumentElement!.SelectNodes("//catalog/book");
+
+        Assert.NotNull(nodes);
+        Assert.Equal(3, nodes.Count);
+    }
+
+    [Fact]
+    public void GivenAnXDocument_WhenSelectingWithXPathSelectElements_ThenReturnsTheSameBooksAsSelectNodes()
+    {
+        var expected = XmlNodesSelector.SelectBooks(_document.DocumentElement!)
+            .Select(x => x.ReplaceLineEndings())
+            .ToList();
+
+        var result = XmlNodesSelector.SelectBooksWithLinqToXml(XDocument.Load("BooksCatalog.xml"))
+            .Select(x => x.ReplaceLineEndings())
+            .ToList();
+
+        Assert.Equal(expected, result);
+    }
+}