add more newline tests (#723)

src/Verify.Tests/NewLineTests.WithNestedNewlineAddedByScrubber.verified.txt

@@ -0,0 +1,7 @@
+{
+  Property:
+value
+line2
+line3
+line4
+}

src/Verify.Tests/NewLineTests.WithRootNewlineAddedByScrubber.verified.txt

@@ -0,0 +1,4 @@
+value
+line2
+line3
+line4

src/Verify.Tests/NewLineTests.cs

@@ -12,6 +12,25 @@ public class NewLineTests
             Property = "F\roo"
         });
 
+    [Fact]
+    public async Task WithRootNewlineAddedByScrubber()
+    {
+        var result = await Verify("value")
+            .AddScrubber(_ => _.Append("\rline2\r\nline3\nline4"));
+        Assert.False(File.ReadAllText(result.Files.Single()).Contains("\r"));
+    }
+
+    [Fact]
+    public async Task WithNestedNewlineAddedByScrubber()
+    {
+        var result = await Verify(new
+            {
+                Property = "value"
+            })
+            .AddScrubber(_ => _.Append("\rline2\r\nline3\nline4"));
+        Assert.False(File.ReadAllText(result.Files.Single()).Contains("\r"));
+    }
+
 #if NET6_0_OR_GREATER
     [Fact]
     public async Task StringWithDifferingNewline()