Netcore: migrate more unittests (#8939)

* Migrated unit tests

* Migrated CoreThings tests

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* Migrated Property Editor unit tests

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* Migrated CoreXml tests

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* Moved more tests

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* revert some IsSZArray test code

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* Renamed bad named test

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

* removed unnecessary file mentions in csproj file

Signed-off-by: Bjarke Berg <mail@bergmania.dk>

Co-authored-by: Elitsa Marinovska <elm@umbraco.dk>

src/Umbraco.Tests.Common/TestHelpers/StringNewlineExtensions.cs

@@ -0,0 +1,44 @@
+namespace Umbraco.Tests
+{
+    public static class StringNewLineExtensions
+    {
+        /// <summary>
+        /// Ensures Lf only everywhere.
+        /// </summary>
+        /// <param name="text">The text to filter.</param>
+        /// <returns>The filtered text.</returns>
+        public static string Lf(this string text)
+        {
+            if (string.IsNullOrEmpty(text)) return text;
+            text = text.Replace("\r", ""); // remove CR
+            return text;
+        }
+
+        /// <summary>
+        /// Ensures CrLf everywhere.
+        /// </summary>
+        /// <param name="text">The text to filter.</param>
+        /// <returns>The filtered text.</returns>
+        public static string CrLf(this string text)
+        {
+            if (string.IsNullOrEmpty(text)) return text;
+            text = text.Replace("\r", ""); // remove CR
+            text = text.Replace("\n", "\r\n"); // add CRLF everywhere
+            return text;
+        }
+
+        /// <summary>
+        /// Replaces Cr/Lf by a single space.
+        /// </summary>
+        /// <param name="text">The text to filter.</param>
+        /// <returns>The filtered text.</returns>
+        public static string NoCrLf(this string text)
+        {
+            if (string.IsNullOrEmpty(text)) return text;
+            text = text.Replace("\r\n", " "); // remove CRLF
+            text = text.Replace("\r", " "); // remove CR
+            text = text.Replace("\n", " "); // remove LF
+            return text;
+        }
+    }
+}