diff --git a/test_suite/tests/test_annotations.rs b/test_suite/tests/test_annotations.rs
index f760085b..2a3e3996 100644
--- a/test_suite/tests/test_annotations.rs
+++ b/test_suite/tests/test_annotations.rs
@@ -2841,11 +2841,66 @@ mod flatten {
 
             #[derive(Debug, PartialEq, Serialize, Deserialize)]
             enum Enum {
+                Tuple(u32, u32),
                 Struct { index: u32, value: u32 },
             }
 
+            /// Reaches crate::private::de::content::VariantDeserializer::tuple_variant
+            /// Content::Seq case
+            /// via FlatMapDeserializer::deserialize_enum
             #[test]
-            fn struct_() {
+            fn tuple() {
+                assert_tokens(
+                    &Flatten {
+                        data: Enum::Tuple(0, 42),
+                        extra: HashMap::from_iter([("extra_key".into(), "extra value".into())]),
+                    },
+                    &[
+                        Token::Map { len: None },
+                        Token::Str("Tuple"), // variant
+                        Token::Seq { len: Some(2) },
+                        Token::U32(0),
+                        Token::U32(42),
+                        Token::SeqEnd,
+                        Token::Str("extra_key"),
+                        Token::Str("extra value"),
+                        Token::MapEnd,
+                    ],
+                );
+            }
+
+            /// Reaches crate::private::de::content::VariantDeserializer::struct_variant
+            /// Content::Seq case
+            /// via FlatMapDeserializer::deserialize_enum
+            #[test]
+            fn struct_from_seq() {
+                assert_de_tokens(
+                    &Flatten {
+                        data: Enum::Struct {
+                            index: 0,
+                            value: 42,
+                        },
+                        extra: HashMap::from_iter([("extra_key".into(), "extra value".into())]),
+                    },
+                    &[
+                        Token::Map { len: None },
+                        Token::Str("Struct"), // variant
+                        Token::Seq { len: Some(2) },
+                        Token::U32(0),  // index
+                        Token::U32(42), // value
+                        Token::SeqEnd,
+                        Token::Str("extra_key"),
+                        Token::Str("extra value"),
+                        Token::MapEnd,
+                    ],
+                );
+            }
+
+            /// Reaches crate::private::de::content::VariantDeserializer::struct_variant
+            /// Content::Map case
+            /// via FlatMapDeserializer::deserialize_enum
+            #[test]
+            fn struct_from_map() {
                 assert_tokens(
                     &Flatten {
                         data: Enum::Struct {
diff --git a/test_suite/tests/test_macros.rs b/test_suite/tests/test_macros.rs
index 0594d8d4..7e700bd2 100644
--- a/test_suite/tests/test_macros.rs
+++ b/test_suite/tests/test_macros.rs
@@ -1430,6 +1430,9 @@ fn test_enum_in_internally_tagged_enum() {
         ],
     );
 
+    // Reaches crate::private::de::content::VariantDeserializer::tuple_variant
+    // Content::Seq case
+    // via ContentDeserializer::deserialize_enum
     assert_tokens(
         &Outer::Inner(Inner::Tuple(1, 1)),
         &[
@@ -1448,6 +1451,9 @@ fn test_enum_in_internally_tagged_enum() {
         ],
     );
 
+    // Reaches crate::private::de::content::VariantDeserializer::struct_variant
+    // Content::Map case
+    // via ContentDeserializer::deserialize_enum
     assert_tokens(
         &Outer::Inner(Inner::Struct { f: 1 }),
         &[
@@ -1465,6 +1471,23 @@ fn test_enum_in_internally_tagged_enum() {
             Token::MapEnd,
         ],
     );
+
+    // Reaches crate::private::de::content::VariantDeserializer::struct_variant
+    // Content::Seq case
+    // via ContentDeserializer::deserialize_enum
+    assert_de_tokens(
+        &Outer::Inner(Inner::Struct { f: 1 }),
+        &[
+            Token::Map { len: Some(2) },
+            Token::Str("type"),
+            Token::Str("Inner"),
+            Token::Str("Struct"),
+            Token::Seq { len: Some(1) },
+            Token::U8(1), // f
+            Token::SeqEnd,
+            Token::MapEnd,
+        ],
+    );
 }
 
 #[test]