Add tests for backlog rendering

src/components/backlog.rs

@@ -25,6 +25,7 @@ use crate::widgets::prerender::{PrerenderInner, PrerenderValue};
 use crate::widgets::{BottomAlignedParagraph, OverlappableWidget};
 
 use super::Component;
+use crate::buffers::BufferItem;
 
 #[derive(Default)]
 pub struct Backlog {
@@ -40,7 +41,7 @@ impl Component for Backlog {
         kind: KeyEventKind::Press,
         state: _,
       } => {
-        self.scroll += 20; // TODO: use the component height
+        self.scroll_up(20); // TODO: use the component height
       },
       KeyEvent {
         code: KeyCode::PageDown,
@@ -48,7 +49,7 @@ impl Component for Backlog {
         kind: KeyEventKind::Press,
         state: _,
       } => {
-        self.scroll = self.scroll.saturating_sub(20); // TODO: use the component height
+        self.scroll_down(20) // TODO: use the component height
       },
       _ => {},
     }
@@ -62,12 +63,37 @@ impl Component for Backlog {
     area: Rect,
     buffers: &crate::buffers::Buffers,
   ) -> Result<()> {
+    let active_buffer = buffers.active_buffer();
+    let items = active_buffer.content();
+    let unused_top_lines = self.draw_items(frame.buffer_mut(), area, items)?;
+
+    // There is empty room on screen, ask the buffer to fetch more backlog if it can
+    if unused_top_lines > 0 {
+      active_buffer.request_back_pagination(100);
+    }
+
+    Ok(())
+  }
+}
+
+impl Backlog {
+  pub fn scroll_up(&mut self, lines: u64) {
+    self.scroll = self.scroll.saturating_add(lines);
+  }
+  pub fn scroll_down(&mut self, lines: u64) {
+    self.scroll = self.scroll.saturating_sub(20);
+  }
+  /// Returns how many lines are unused at the top of the area.
+  pub fn draw_items<'a>(
+    &mut self,
+    frame_buffer: &mut Buffer,
+    area: Rect,
+    mut items: impl Iterator<Item = BufferItem<'a>>,
+  ) -> Result<u16> {
     let block = Block::new().borders(Borders::ALL);
     let mut text_area = block.inner(area);
-    block.render(area, frame.buffer_mut());
+    block.render(area, frame_buffer);
 
-    let active_buffer = buffers.active_buffer();
-    let mut items = active_buffer.content();
     let mut scroll = self.scroll;
 
     // Skip widgets at the bottom (if scrolled up), and render the first visible one
@@ -103,7 +129,7 @@ impl Component for Backlog {
 
       // TODO: cache this
       let widget = BottomAlignedParagraph::new(item.text).scroll(scroll);
-      let height = widget.render_overlap(text_area, frame.buffer_mut());
+      let height = widget.render_overlap(text_area, frame_buffer);
       text_area.height = text_area.height.saturating_sub(height);
 
       scroll = scroll.saturating_sub(expected_height);
@@ -113,7 +139,7 @@ impl Component for Backlog {
     }
     if text_area.height == 0 {
       // No more room to display other paragraphs, stop now
-      return Ok(());
+      return Ok(0);
     }
 
     // Render other widgets
@@ -135,7 +161,7 @@ impl Component for Backlog {
               width: text_area.width,
               height: buf.area.height - skip_top_lines,
             },
-            frame.buffer_mut(),
+            frame_buffer,
             Rect {
               y: text_area.y + top_padding,
               height: text_area.height - top_padding,
@@ -147,7 +173,7 @@ impl Component for Backlog {
         },
         prerender => {
           let widget = BottomAlignedParagraph::new(item.text);
-          let height = widget.render_overlap(text_area, frame.buffer_mut());
+          let height = widget.render_overlap(text_area, frame_buffer);
 
           // If the whole widget fits in the text_area, copy the drawn result to a buffer
           // for caching
@@ -160,7 +186,7 @@ impl Component for Backlog {
             });
             let top_padding = text_area.height.saturating_sub(buf.area.height);
             copy_buffer(
-              frame.buffer_mut(),
+              frame_buffer,
               Rect {
                 y: text_area.y + top_padding,
                 height: text_area.height - top_padding,
@@ -188,14 +214,11 @@ impl Component for Backlog {
       text_area.height = text_area.height.saturating_sub(height); // Remove lines at the bottom used by this paragraph
       if text_area.height == 0 {
         // No more room to display other paragraphs, stop now
-        return Ok(());
+        return Ok(0);
       }
     }
 
-    // There is empty room on screen, ask the buffer to fetch more backlog if it can
+    Ok(text_area.height)
-    active_buffer.request_back_pagination(100);
-
-    Ok(())
   }
 }
 

src/lib.rs

@@ -0,0 +1,23 @@
+#![allow(dead_code)]
+#![allow(unused_imports)]
+#![allow(unused_variables)]
+
+pub mod action;
+pub mod app;
+pub mod buffers;
+pub mod cli;
+pub mod commands;
+pub mod components;
+pub mod config;
+pub mod log;
+pub mod mode;
+pub mod plugins;
+pub mod tui;
+pub mod utils;
+pub mod widgets;
+
+use crate::{
+  app::App,
+  log::initialize_logging,
+  utils::{initialize_panic_handler, version},
+};

src/main.rs

@@ -1,30 +1,7 @@
-#![allow(dead_code)]
-#![allow(unused_imports)]
-#![allow(unused_variables)]
-
-pub mod action;
-pub mod app;
-pub mod buffers;
-pub mod cli;
-pub mod commands;
-pub mod components;
-pub mod config;
-pub mod log;
-pub mod mode;
-pub mod plugins;
-pub mod tui;
-pub mod utils;
-pub mod widgets;
-
 use clap::Parser;
-use cli::Cli;
 use color_eyre::eyre::Result;
 
-use crate::{
+use ratatrix::{app::App, cli::Cli, log::initialize_logging, utils::initialize_panic_handler};
-  app::App,
-  log::initialize_logging,
-  utils::{initialize_panic_handler, version},
-};
 
 async fn tokio_main() -> Result<()> {
   let mem_log = initialize_logging()?;

src/widgets/prerender.rs

@@ -36,4 +36,11 @@ impl Prerender {
   pub fn new() -> Prerender {
     Prerender(Arc::new(Mutex::new(None)))
   }
+
+  /// If this cache contains anything, returns its key
+  ///
+  /// This is only meant for testing
+  pub fn key(&self) -> Option<u16> {
+    self.0.lock().unwrap().as_ref().map(|inner| inner.key)
+  }
 }

tests/components/backlog.rs

@@ -0,0 +1,344 @@
+/*
+ * Copyright (C) 2023  Valentin Lorentz
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+use color_eyre::eyre::WrapErr;
+use pretty_assertions::assert_eq;
+use ratatui::prelude::*;
+
+use ratatrix::buffers::BufferItem;
+use ratatrix::components::Backlog;
+use ratatrix::widgets::Prerender;
+
+fn rect(x: u16, y: u16, width: u16, height: u16) -> Rect {
+  Rect {
+    x,
+    y,
+    width,
+    height,
+  }
+}
+
+#[test]
+fn test_single_item() {
+  let mut bl = Backlog::default();
+  let prerender = Prerender::new();
+  let item = BufferItem {
+    text: Text::raw("hello"),
+    prerender: &prerender,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 18, 8));
+  bl.draw_items(&mut buf, rect(3, 2, 12, 4), vec![item].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "                  ",
+    "                  ",
+    "   ┌──────────┐   ",
+    "   │          │   ",
+    "   │hello     │   ",
+    "   └──────────┘   ",
+    "                  ",
+    "                  ",
+  ]);
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_single_item_cached() {
+  let mut bl = Backlog::default();
+  let prerender = Prerender::new();
+  let item = BufferItem {
+    text: Text::raw("hello"),
+    prerender: &prerender,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 18, 8));
+  let area = rect(3, 2, 12, 4);
+  bl.draw_items(&mut buf, area, vec![item].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "                  ",
+    "                  ",
+    "   ┌──────────┐   ",
+    "   │          │   ",
+    "   │hello     │   ",
+    "   └──────────┘   ",
+    "                  ",
+    "                  ",
+  ]);
+  assert_eq!(buf, expected);
+
+  assert_eq!(prerender.key(), Some(10));
+
+  let item = BufferItem {
+    text: Text::raw("hello"),
+    prerender: &prerender,
+  };
+  bl.draw_items(&mut buf, area, vec![item].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_single_item_tight() {
+  let mut bl = Backlog::default();
+  let prerender = Prerender::new();
+  let item = BufferItem {
+    text: Text::raw("hello"),
+    prerender: &prerender,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 13, 7));
+  bl.draw_items(&mut buf, rect(3, 2, 7, 3), vec![item].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "             ",
+    "             ",
+    "   ┌─────┐   ",
+    "   │hello│   ",
+    "   └─────┘   ",
+    "             ",
+    "             ",
+  ]);
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_two_items() {
+  let mut bl = Backlog::default();
+  let prerender1 = Prerender::new();
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let prerender2 = Prerender::new();
+  let item2 = BufferItem {
+    text: Text::raw("world"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │          │ ",
+    " │hi        │ ",
+    " │world     │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_two_items_scroll() {
+  let mut bl = Backlog::default();
+  let prerender1 = Prerender::new();
+  let prerender2 = Prerender::new();
+
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let item2 = BufferItem {
+    text: Text::raw("world"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │          │ ",
+    " │hi        │ ",
+    " │world     │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+
+  bl.scroll_up(1);
+
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let item2 = BufferItem {
+    text: Text::raw("world"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │          │ ",
+    " │          │ ",
+    " │hi        │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+
+  bl.scroll_up(1);
+
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let item2 = BufferItem {
+    text: Text::raw("world"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │          │ ",
+    " │          │ ",
+    " │          │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_two_items_multiline() {
+  let mut bl = Backlog::default();
+  let prerender1 = Prerender::new();
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let prerender2 = Prerender::new();
+  let item2 = BufferItem {
+    text: Text::raw("world\n!"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │hi        │ ",
+    " │world     │ ",
+    " │!         │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_two_items_tight() {
+  let mut bl = Backlog::default();
+  let prerender1 = Prerender::new();
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let prerender2 = Prerender::new();
+  let item2 = BufferItem {
+    text: Text::raw("world"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 9, 6));
+  bl.draw_items(&mut buf, rect(1, 1, 7, 4), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+
+  let expected = Buffer::with_lines(vec![
+    "         ",
+    " ┌─────┐ ",
+    " │hi   │ ",
+    " │world│ ",
+    " └─────┘ ",
+    "         ",
+  ]);
+  assert_eq!(buf, expected);
+}
+
+#[test]
+fn test_cache_moved() {
+  let mut bl = Backlog::default();
+  let prerender1 = Prerender::new();
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+
+  // Draw once
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │          │ ",
+    " │          │ ",
+    " │hi        │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+
+  // New item added at bottom
+  let item1 = BufferItem {
+    text: Text::raw("hi"),
+    prerender: &prerender1,
+  };
+  let prerender2 = Prerender::new();
+  let item2 = BufferItem {
+    text: Text::raw("world"),
+    prerender: &prerender2,
+  };
+  let mut buf = Buffer::empty(rect(0, 0, 14, 7));
+  bl.draw_items(&mut buf, rect(1, 1, 12, 5), vec![item2, item1].into_iter())
+    .context("Failed to draw")
+    .unwrap();
+  let expected = Buffer::with_lines(vec![
+    "              ",
+    " ┌──────────┐ ",
+    " │          │ ",
+    " │hi        │ ",
+    " │world     │ ",
+    " └──────────┘ ",
+    "              ",
+  ]);
+  assert_eq!(buf, expected);
+}

tests/components/main.rs

@@ -0,0 +1 @@
+mod backlog;