Always write an object for ClaimsPrincipal

src/Verify.Tests/Serialization/ClaimsTests.ClaimsPrincipalWithIdentity.verified.txt

@@ -0,0 +1,15 @@
+{
+  Principal: {
+    Identities: [
+      {
+        Claims: [
+          {
+            TheClaimType: TheClaimValue
+          }
+        ],
+        AuthenticationType: TheAuthenticationType
+      }
+    ]
+  },
+  Name: TheValue
+}

src/Verify.Tests/Serialization/ClaimsTests.EmptyClaimsPrincipal.verified.txt

@@ -0,0 +1,4 @@
+{
+  Principal: {},
+  Name: TheValue
+}

src/Verify.Tests/Serialization/ClaimsTests.cs

@@ -0,0 +1,25 @@
+public class ClaimsTests
+{
+    [Fact]
+    public Task EmptyClaimsPrincipal() =>
+        // An empty principal still writes an object. Writing no token would leave the
+        // writer mid-property and corrupt every member written after it.
+        Verify(
+            new
+            {
+                Principal = new ClaimsPrincipal(),
+                Name = "TheValue"
+            });
+
+    [Fact]
+    public Task ClaimsPrincipalWithIdentity() =>
+        Verify(
+            new
+            {
+                Principal = new ClaimsPrincipal(
+                    new ClaimsIdentity(
+                        [new Claim("TheClaimType", "TheClaimValue")],
+                        "TheAuthenticationType")),
+                Name = "TheValue"
+            });
+}

src/Verify/Serialization/Converters/ClaimsPrincipalConverter.cs

@@ -5,11 +5,10 @@ class ClaimsPrincipalConverter :
 {
     public override void Write(VerifyJsonWriter writer, ClaimsPrincipal principal)
     {
-        if (!principal.Identities.Any())
-        {
-            return;
-        }
-
+        // The object is always written, even with no identities. Writing no token at all
+        // leaves the writer in Property state after the caller has written the member
+        // name, which corrupts every subsequent write. WriteMember drops the empty
+        // Identities collection, so an empty principal renders as {}.
         writer.WriteStartObject();
         writer.WriteMember(principal, principal.Identities, "Identities");
         writer.WriteEndObject();