Add polyfill for splitting on a single char or string

Author: jnyrup

Src/FluentAssertions/Common/MemberPath.cs

@@ -116,7 +116,7 @@ public bool HasSameParentAs(MemberPath path)
     private string[] Segments =>
         segments ??= dottedPath
             .Replace("[]", "[*]", StringComparison.Ordinal)
-            .Split(new[] { '.', '[', ']' }, StringSplitOptions.RemoveEmptyEntries);
+            .Split(['.', '[', ']'], StringSplitOptions.RemoveEmptyEntries);
 
     /// <summary>
     /// Returns a copy of the current object as if it represented an un-indexed item in a collection.

Src/FluentAssertions/Common/StringExtensions.cs

@@ -103,7 +103,7 @@ public static string Capitalize(this string @this)
     public static string IndentLines(this string @this)
     {
         return string.Join(Environment.NewLine,
-            @this.Split(new[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries).Select(x => $"\t{x}"));
+            @this.Split(['\r', '\n'], StringSplitOptions.RemoveEmptyEntries).Select(x => $"\t{x}"));
     }
 
     public static string RemoveNewLines(this string @this)

Src/FluentAssertions/Equivalency/Execution/ObjectReference.cs

@@ -39,7 +39,7 @@ public override bool Equals(object obj)
 
     private string[] GetPathElements() => pathElements
         ??= path.ToUpperInvariant().Replace("][", "].[", StringComparison.Ordinal)
-            .Split(new[] { '.' }, StringSplitOptions.RemoveEmptyEntries);
+            .Split('.', StringSplitOptions.RemoveEmptyEntries);
 
     private bool IsParentOrChildOf(ObjectReference other)
     {

Src/FluentAssertions/Equivalency/Tracing/StringBuilderTraceWriter.cs

@@ -28,7 +28,7 @@ public IDisposable AddBlock(string trace)
 
     private void WriteLine(string trace)
     {
-        foreach (string traceLine in trace.Split([Environment.NewLine], StringSplitOptions.RemoveEmptyEntries))
+        foreach (string traceLine in trace.Split(Environment.NewLine, StringSplitOptions.RemoveEmptyEntries))
         {
             builder.Append(new string(' ', depth * 2)).AppendLine(traceLine);
         }

Src/FluentAssertions/Formatting/XElementValueFormatter.cs

@@ -48,6 +48,6 @@ private static string FormatElementWithChildren(XElement element)
     private static string[] SplitIntoSeparateLines(XElement element)
     {
         string formattedXml = element.ToString();
-        return formattedXml.Split([Environment.NewLine], StringSplitOptions.None);
+        return formattedXml.Split(Environment.NewLine, StringSplitOptions.None);
     }
 }

Src/FluentAssertions/Polyfill/SystemExtensions.cs

@@ -23,6 +23,12 @@ public static bool Contains(this string str, char value, StringComparison compar
     // https://source.dot.net/#System.Private.CoreLib/src/libraries/System.Private.CoreLib/src/System/String.Comparison.cs,1014
     public static bool StartsWith(this string str, char value) =>
         str.Length != 0 && str[0] == value;
+
+    public static string[] Split(this string str, char separator, StringSplitOptions options = StringSplitOptions.None) =>
+        str.Split([separator], options);
+
+    public static string[] Split(this string str, string separator, StringSplitOptions options = StringSplitOptions.None) =>
+        str.Split([separator], options);
 }
 
 #endif