From c09e2bd690b2e12cd355e93ca4c9beb8b3ff98e9 Mon Sep 17 00:00:00 2001
From: Mingun <alexander_sergey@mail.ru>
Date: Sat, 3 Aug 2024 16:02:38 +0500
Subject: [PATCH] Add tests for flatten unit variant in adjacently tagged (tag
 + content) enums

---
 test_suite/tests/test_annotations.rs | 165 +++++++++++++++++++++++++++
 1 file changed, 165 insertions(+)

diff --git a/test_suite/tests/test_annotations.rs b/test_suite/tests/test_annotations.rs
index 35de0f2c..510ce5d0 100644
--- a/test_suite/tests/test_annotations.rs
+++ b/test_suite/tests/test_annotations.rs
@@ -2898,6 +2898,7 @@ mod flatten {
             #[derive(Debug, PartialEq, Serialize, Deserialize)]
             #[serde(tag = "tag", content = "content")]
             enum Enum {
+                Unit,
                 Newtype(NewtypeVariant),
                 Struct { index: u32, value: u32 },
             }
@@ -2907,6 +2908,170 @@ mod flatten {
                 value: u32,
             }
 
+            #[test]
+            fn unit() {
+                let value = Flatten {
+                    outer: 42,
+                    data: NewtypeWrapper(Enum::Unit),
+                };
+                // Field order: outer, [tag]
+                assert_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        // content missing
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: [tag], outer
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        // content missing
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: outer, [tag, content]
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        // content
+                        Token::Str("content"),
+                        Token::Unit,
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: outer, [content, tag]
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        // content
+                        Token::Str("content"),
+                        Token::Unit,
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: [tag, content], outer
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        // content
+                        Token::Str("content"),
+                        Token::Unit,
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: [content, tag], outer - did not work
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // content
+                        Token::Str("content"),
+                        Token::Unit,
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: [tag], outer, [content]
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        // content
+                        Token::Str("content"),
+                        Token::Unit,
+                        Token::MapEnd,
+                    ],
+                );
+                // Field order: [content], outer, [tag] - did not work
+                assert_de_tokens(
+                    &value,
+                    &[
+                        Token::Map { len: None },
+                        // content
+                        Token::Str("content"),
+                        Token::Unit,
+                        // outer
+                        Token::Str("outer"),
+                        Token::U32(42),
+                        // tag
+                        Token::Str("tag"),
+                        Token::UnitVariant {
+                            name: "Enum",
+                            variant: "Unit",
+                        },
+                        Token::MapEnd,
+                    ],
+                );
+            }
+
             #[test]
             fn newtype() {
                 let value = Flatten {