Add visual TUI test coverage

tests/screens.rs

@@ -4,8 +4,10 @@ mod helpers;
 
 use helpers::app_builder::TestAppBuilder;
 use helpers::snapshot_utils::{buffer_to_string, render_to_buffer};
-use helpers::test_data::create_test_chat;
+use helpers::test_data::{create_test_chat, TestChatBuilder, TestMessageBuilder};
 use insta::assert_snapshot;
+use tele_tui::accounts::AccountProfile;
+use tele_tui::app::AccountSwitcherState;
 use tele_tui::app::AppScreen;
 use tele_tui::tdlib::AuthState;
 
@@ -113,3 +115,114 @@ fn snapshot_main_screen_terminal_too_small() {
     let output = buffer_to_string(&buffer);
     assert_snapshot!("main_screen_terminal_too_small", output);
 }
+
+#[test]
+fn snapshot_main_screen_chat_list_loaded() {
+    let mut app = TestAppBuilder::new()
+        .screen(AppScreen::Main)
+        .with_chats(sample_chats())
+        .build();
+
+    let buffer = render_to_buffer(100, 30, |f| {
+        tele_tui::ui::render(f, &mut app);
+    });
+
+    let output = buffer_to_string(&buffer);
+    assert_snapshot!("main_screen_chat_list_loaded", output);
+}
+
+#[test]
+fn snapshot_main_screen_chat_open_with_messages() {
+    let mut app = TestAppBuilder::new()
+        .screen(AppScreen::Main)
+        .with_chats(sample_chats())
+        .selected_chat(102)
+        .with_messages(102, sample_work_messages())
+        .message_input("Draft reply")
+        .insert_mode()
+        .build();
+
+    let buffer = render_to_buffer(100, 30, |f| {
+        tele_tui::ui::render(f, &mut app);
+    });
+
+    let output = buffer_to_string(&buffer);
+    assert_snapshot!("main_screen_chat_open_with_messages", output);
+}
+
+#[test]
+fn snapshot_main_screen_chat_open_narrow_valid() {
+    let mut app = TestAppBuilder::new()
+        .screen(AppScreen::Main)
+        .with_chats(sample_chats())
+        .selected_chat(102)
+        .with_messages(102, sample_work_messages())
+        .build();
+
+    let buffer = render_to_buffer(60, 16, |f| {
+        tele_tui::ui::render(f, &mut app);
+    });
+
+    let output = buffer_to_string(&buffer);
+    assert_snapshot!("main_screen_chat_open_narrow_valid", output);
+}
+
+#[test]
+fn snapshot_main_screen_account_switcher_overlay() {
+    let mut app = TestAppBuilder::new()
+        .screen(AppScreen::Main)
+        .with_chats(sample_chats())
+        .build();
+    app.current_account_name = "personal".to_string();
+    app.account_switcher = Some(AccountSwitcherState::SelectAccount {
+        accounts: vec![
+            AccountProfile {
+                name: "personal".to_string(),
+                display_name: "Personal".to_string(),
+            },
+            AccountProfile {
+                name: "work".to_string(),
+                display_name: "Work".to_string(),
+            },
+        ],
+        selected_index: 1,
+        current_account: "personal".to_string(),
+    });
+
+    let buffer = render_to_buffer(100, 30, |f| {
+        tele_tui::ui::render(f, &mut app);
+    });
+
+    let output = buffer_to_string(&buffer);
+    assert_snapshot!("main_screen_account_switcher_overlay", output);
+}
+
+fn sample_chats() -> Vec<tele_tui::tdlib::ChatInfo> {
+    vec![
+        TestChatBuilder::new("Mom", 101)
+            .last_message("Dinner at 7?")
+            .unread_count(2)
+            .build(),
+        TestChatBuilder::new("Work Group", 102)
+            .last_message("Standup notes are ready")
+            .unread_mentions(1)
+            .build(),
+        TestChatBuilder::new("Boss", 103)
+            .last_message("Please review the deck")
+            .build(),
+    ]
+}
+
+fn sample_work_messages() -> Vec<tele_tui::tdlib::MessageInfo> {
+    vec![
+        TestMessageBuilder::new("Morning, team", 201)
+            .sender("Alice")
+            .build(),
+        TestMessageBuilder::new("Standup notes are ready", 202)
+            .sender("Bob")
+            .build(),
+        TestMessageBuilder::new("Thanks, I will review them after lunch", 203)
+            .outgoing()
+            .build(),
+    ]
+}