Inline tui as helix-tui fork.

We only rely on some of the rendering primitives and implement our
Cursive-style compositor on top.

5 files changed, 1274 insertions, 0 deletions

diff --git a/helix-tui/tests/terminal.rs b/helix-tui/tests/terminal.rs
new file mode 100644
index 00000000..4734dd9a
--- /dev/null
+++ b/helix-tui/tests/terminal.rs
@@ -0,0 +1,36 @@
+use helix_tui::{
+    backend::{Backend, TestBackend},
+    layout::Rect,
+    widgets::Paragraph,
+    Terminal,
+};
+use std::error::Error;
+
+#[test]
+fn terminal_buffer_size_should_be_limited() {
+    let backend = TestBackend::new(400, 400);
+    let terminal = Terminal::new(backend).unwrap();
+    let size = terminal.backend().size().unwrap();
+    assert_eq!(size.width, 255);
+    assert_eq!(size.height, 255);
+}
+
+// #[test]
+// fn terminal_draw_returns_the_completed_frame() -> Result<(), Box<dyn Error>> {
+//     let backend = TestBackend::new(10, 10);
+//     let mut terminal = Terminal::new(backend)?;
+//     let frame = terminal.draw(|f| {
+//         let paragrah = Paragraph::new("Test");
+//         f.render_widget(paragrah, f.size());
+//     })?;
+//     assert_eq!(frame.buffer.get(0, 0).symbol, "T");
+//     assert_eq!(frame.area, Rect::new(0, 0, 10, 10));
+//     terminal.backend_mut().resize(8, 8);
+//     let frame = terminal.draw(|f| {
+//         let paragrah = Paragraph::new("test");
+//         f.render_widget(paragrah, f.size());
+//     })?;
+//     assert_eq!(frame.buffer.get(0, 0).symbol, "t");
+//     assert_eq!(frame.area, Rect::new(0, 0, 8, 8));
+//     Ok(())
+// }
diff --git a/helix-tui/tests/widgets_block.rs b/helix-tui/tests/widgets_block.rs
new file mode 100644
index 00000000..8aaf905b
--- /dev/null
+++ b/helix-tui/tests/widgets_block.rs
@@ -0,0 +1,213 @@
+use helix_tui::{
+    backend::TestBackend,
+    buffer::Buffer,
+    layout::Rect,
+    style::{Color, Style},
+    text::Span,
+    widgets::{Block, Borders},
+    Terminal,
+};
+
+#[test]
+fn widgets_block_renders() {
+    let backend = TestBackend::new(10, 10);
+    let mut terminal = Terminal::new(backend).unwrap();
+    terminal
+        .draw(|f| {
+            let block = Block::default()
+                .title(Span::styled("Title", Style::default().fg(Color::LightBlue)))
+                .borders(Borders::ALL);
+            f.render_widget(
+                block,
+                Rect {
+                    x: 0,
+                    y: 0,
+                    width: 8,
+                    height: 8,
+                },
+            );
+        })
+        .unwrap();
+    let mut expected = Buffer::with_lines(vec![
+        "┌Title─┐  ",
+        "│      │  ",
+        "│      │  ",
+        "│      │  ",
+        "│      │  ",
+        "│      │  ",
+        "│      │  ",
+        "└──────┘  ",
+        "          ",
+        "          ",
+    ]);
+    for x in 1..=5 {
+        expected.get_mut(x, 0).set_fg(Color::LightBlue);
+    }
+    terminal.backend().assert_buffer(&expected);
+}
+
+#[test]
+fn widgets_block_renders_on_small_areas() {
+    let test_case = |block, area: Rect, expected| {
+        let backend = TestBackend::new(area.width, area.height);
+        let mut terminal = Terminal::new(backend).unwrap();
+        terminal
+            .draw(|f| {
+                f.render_widget(block, area);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    let one_cell_test_cases = [
+        (Borders::NONE, "T"),
+        (Borders::LEFT, "│"),
+        (Borders::TOP, "T"),
+        (Borders::RIGHT, "│"),
+        (Borders::BOTTOM, "T"),
+        (Borders::ALL, "┌"),
+    ];
+    for (borders, symbol) in one_cell_test_cases.iter().cloned() {
+        test_case(
+            Block::default().title("Test").borders(borders),
+            Rect {
+                x: 0,
+                y: 0,
+                width: 0,
+                height: 0,
+            },
+            Buffer::empty(Rect {
+                x: 0,
+                y: 0,
+                width: 0,
+                height: 0,
+            }),
+        );
+        test_case(
+            Block::default().title("Test").borders(borders),
+            Rect {
+                x: 0,
+                y: 0,
+                width: 1,
+                height: 0,
+            },
+            Buffer::empty(Rect {
+                x: 0,
+                y: 0,
+                width: 1,
+                height: 0,
+            }),
+        );
+        test_case(
+            Block::default().title("Test").borders(borders),
+            Rect {
+                x: 0,
+                y: 0,
+                width: 0,
+                height: 1,
+            },
+            Buffer::empty(Rect {
+                x: 0,
+                y: 0,
+                width: 0,
+                height: 1,
+            }),
+        );
+        test_case(
+            Block::default().title("Test").borders(borders),
+            Rect {
+                x: 0,
+                y: 0,
+                width: 1,
+                height: 1,
+            },
+            Buffer::with_lines(vec![symbol]),
+        );
+    }
+    test_case(
+        Block::default().title("Test").borders(Borders::LEFT),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 4,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["│Tes"]),
+    );
+    test_case(
+        Block::default().title("Test").borders(Borders::RIGHT),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 4,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["Tes│"]),
+    );
+    test_case(
+        Block::default().title("Test").borders(Borders::RIGHT),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 4,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["Tes│"]),
+    );
+    test_case(
+        Block::default()
+            .title("Test")
+            .borders(Borders::LEFT | Borders::RIGHT),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 4,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["│Te│"]),
+    );
+    test_case(
+        Block::default().title("Test").borders(Borders::TOP),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 4,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["Test"]),
+    );
+    test_case(
+        Block::default().title("Test").borders(Borders::TOP),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 5,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["Test─"]),
+    );
+    test_case(
+        Block::default()
+            .title("Test")
+            .borders(Borders::LEFT | Borders::TOP),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 5,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["┌Test"]),
+    );
+    test_case(
+        Block::default()
+            .title("Test")
+            .borders(Borders::LEFT | Borders::TOP),
+        Rect {
+            x: 0,
+            y: 0,
+            width: 6,
+            height: 1,
+        },
+        Buffer::with_lines(vec!["┌Test─"]),
+    );
+}
diff --git a/helix-tui/tests/widgets_list.rs b/helix-tui/tests/widgets_list.rs
new file mode 100644
index 00000000..e59accd8
--- /dev/null
+++ b/helix-tui/tests/widgets_list.rs
@@ -0,0 +1,88 @@
+use helix_tui::{
+    backend::TestBackend,
+    buffer::Buffer,
+    layout::Rect,
+    style::{Color, Style},
+    symbols,
+    widgets::{Block, Borders, List, ListItem, ListState},
+    Terminal,
+};
+
+#[test]
+fn widgets_list_should_highlight_the_selected_item() {
+    let backend = TestBackend::new(10, 3);
+    let mut terminal = Terminal::new(backend).unwrap();
+    let mut state = ListState::default();
+    state.select(Some(1));
+    terminal
+        .draw(|f| {
+            let size = f.size();
+            let items = vec![
+                ListItem::new("Item 1"),
+                ListItem::new("Item 2"),
+                ListItem::new("Item 3"),
+            ];
+            let list = List::new(items)
+                .highlight_style(Style::default().bg(Color::Yellow))
+                .highlight_symbol(">> ");
+            f.render_stateful_widget(list, size, &mut state);
+        })
+        .unwrap();
+    let mut expected = Buffer::with_lines(vec!["   Item 1 ", ">> Item 2 ", "   Item 3 "]);
+    for x in 0..10 {
+        expected.get_mut(x, 1).set_bg(Color::Yellow);
+    }
+    terminal.backend().assert_buffer(&expected);
+}
+
+#[test]
+fn widgets_list_should_truncate_items() {
+    let backend = TestBackend::new(10, 2);
+    let mut terminal = Terminal::new(backend).unwrap();
+
+    struct TruncateTestCase<'a> {
+        selected: Option<usize>,
+        items: Vec<ListItem<'a>>,
+        expected: Buffer,
+    }
+
+    let cases = vec![
+        // An item is selected
+        TruncateTestCase {
+            selected: Some(0),
+            items: vec![
+                ListItem::new("A very long line"),
+                ListItem::new("A very long line"),
+            ],
+            expected: Buffer::with_lines(vec![
+                format!(">> A ve{}  ", symbols::line::VERTICAL),
+                format!("   A ve{}  ", symbols::line::VERTICAL),
+            ]),
+        },
+        // No item is selected
+        TruncateTestCase {
+            selected: None,
+            items: vec![
+                ListItem::new("A very long line"),
+                ListItem::new("A very long line"),
+            ],
+            expected: Buffer::with_lines(vec![
+                format!("A very {}  ", symbols::line::VERTICAL),
+                format!("A very {}  ", symbols::line::VERTICAL),
+            ]),
+        },
+    ];
+    for case in cases {
+        let mut state = ListState::default();
+        state.select(case.selected);
+        terminal
+            .draw(|f| {
+                let list = List::new(case.items.clone())
+                    .block(Block::default().borders(Borders::RIGHT))
+                    .highlight_symbol(">> ");
+                f.render_stateful_widget(list, Rect::new(0, 0, 8, 2), &mut state);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&case.expected);
+    }
+}
diff --git a/helix-tui/tests/widgets_paragraph.rs b/helix-tui/tests/widgets_paragraph.rs
new file mode 100644
index 00000000..33d693d8
--- /dev/null
+++ b/helix-tui/tests/widgets_paragraph.rs
@@ -0,0 +1,220 @@
+use helix_tui::{
+    backend::TestBackend,
+    buffer::Buffer,
+    layout::Alignment,
+    text::{Span, Spans, Text},
+    widgets::{Block, Borders, Paragraph, Wrap},
+    Terminal,
+};
+
+const SAMPLE_STRING: &str = "The library is based on the principle of immediate rendering with \
+     intermediate buffers. This means that at each new frame you should build all widgets that are \
+     supposed to be part of the UI. While providing a great flexibility for rich and \
+     interactive UI, this may introduce overhead for highly dynamic content.";
+
+#[test]
+fn widgets_paragraph_can_wrap_its_content() {
+    let test_case = |alignment, expected| {
+        let backend = TestBackend::new(20, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let text = vec![Spans::from(SAMPLE_STRING)];
+                let paragraph = Paragraph::new(text)
+                    .block(Block::default().borders(Borders::ALL))
+                    .alignment(alignment)
+                    .wrap(Wrap { trim: true });
+                f.render_widget(paragraph, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    test_case(
+        Alignment::Left,
+        Buffer::with_lines(vec![
+            "┌──────────────────┐",
+            "│The library is    │",
+            "│based on the      │",
+            "│principle of      │",
+            "│immediate         │",
+            "│rendering with    │",
+            "│intermediate      │",
+            "│buffers. This     │",
+            "│means that at each│",
+            "└──────────────────┘",
+        ]),
+    );
+    test_case(
+        Alignment::Right,
+        Buffer::with_lines(vec![
+            "┌──────────────────┐",
+            "│    The library is│",
+            "│      based on the│",
+            "│      principle of│",
+            "│         immediate│",
+            "│    rendering with│",
+            "│      intermediate│",
+            "│     buffers. This│",
+            "│means that at each│",
+            "└──────────────────┘",
+        ]),
+    );
+    test_case(
+        Alignment::Center,
+        Buffer::with_lines(vec![
+            "┌──────────────────┐",
+            "│  The library is  │",
+            "│   based on the   │",
+            "│   principle of   │",
+            "│     immediate    │",
+            "│  rendering with  │",
+            "│   intermediate   │",
+            "│   buffers. This  │",
+            "│means that at each│",
+            "└──────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_paragraph_renders_double_width_graphemes() {
+    let backend = TestBackend::new(10, 10);
+    let mut terminal = Terminal::new(backend).unwrap();
+
+    let s = "コンピュータ上で文字を扱う場合、典型的には文字による通信を行う場合にその両端点では、";
+    terminal
+        .draw(|f| {
+            let size = f.size();
+            let text = vec![Spans::from(s)];
+            let paragraph = Paragraph::new(text)
+                .block(Block::default().borders(Borders::ALL))
+                .wrap(Wrap { trim: true });
+            f.render_widget(paragraph, size);
+        })
+        .unwrap();
+
+    let expected = Buffer::with_lines(vec![
+        "┌────────┐",
+        "│コンピュ│",
+        "│ータ上で│",
+        "│文字を扱│",
+        "│う場合、│",
+        "│典型的に│",
+        "│は文字に│",
+        "│よる通信│",
+        "│を行う場│",
+        "└────────┘",
+    ]);
+    terminal.backend().assert_buffer(&expected);
+}
+
+#[test]
+fn widgets_paragraph_renders_mixed_width_graphemes() {
+    let backend = TestBackend::new(10, 7);
+    let mut terminal = Terminal::new(backend).unwrap();
+
+    let s = "aコンピュータ上で文字を扱う場合、";
+    terminal
+        .draw(|f| {
+            let size = f.size();
+            let text = vec![Spans::from(s)];
+            let paragraph = Paragraph::new(text)
+                .block(Block::default().borders(Borders::ALL))
+                .wrap(Wrap { trim: true });
+            f.render_widget(paragraph, size);
+        })
+        .unwrap();
+
+    let expected = Buffer::with_lines(vec![
+        // The internal width is 8 so only 4 slots for double-width characters.
+        "┌────────┐",
+        "│aコンピ │", // Here we have 1 latin character so only 3 double-width ones can fit.
+        "│ュータ上│",
+        "│で文字を│",
+        "│扱う場合│",
+        "│、      │",
+        "└────────┘",
+    ]);
+    terminal.backend().assert_buffer(&expected);
+}
+
+#[test]
+fn widgets_paragraph_can_wrap_with_a_trailing_nbsp() {
+    let nbsp: &str = "\u{00a0}";
+    let line = Spans::from(vec![Span::raw("NBSP"), Span::raw(nbsp)]);
+    let backend = TestBackend::new(20, 3);
+    let mut terminal = Terminal::new(backend).unwrap();
+    let expected = Buffer::with_lines(vec![
+        "┌──────────────────┐",
+        "│NBSP\u{00a0}             │",
+        "└──────────────────┘",
+    ]);
+    terminal
+        .draw(|f| {
+            let size = f.size();
+
+            let paragraph = Paragraph::new(line).block(Block::default().borders(Borders::ALL));
+            f.render_widget(paragraph, size);
+        })
+        .unwrap();
+    terminal.backend().assert_buffer(&expected);
+}
+#[test]
+fn widgets_paragraph_can_scroll_horizontally() {
+    let test_case = |alignment, scroll, expected| {
+        let backend = TestBackend::new(20, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let text = Text::from(
+                    "段落现在可以水平滚动了！\nParagraph can scroll horizontally!\nShort line",
+                );
+                let paragraph = Paragraph::new(text)
+                    .block(Block::default().borders(Borders::ALL))
+                    .alignment(alignment)
+                    .scroll(scroll);
+                f.render_widget(paragraph, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    test_case(
+        Alignment::Left,
+        (0, 7),
+        Buffer::with_lines(vec![
+            "┌──────────────────┐",
+            "│在可以水平滚动了！│",
+            "│ph can scroll hori│",
+            "│ine               │",
+            "│                  │",
+            "│                  │",
+            "│                  │",
+            "│                  │",
+            "│                  │",
+            "└──────────────────┘",
+        ]),
+    );
+    // only support Alignment::Left
+    test_case(
+        Alignment::Right,
+        (0, 7),
+        Buffer::with_lines(vec![
+            "┌──────────────────┐",
+            "│段落现在可以水平滚│",
+            "│Paragraph can scro│",
+            "│        Short line│",
+            "│                  │",
+            "│                  │",
+            "│                  │",
+            "│                  │",
+            "│                  │",
+            "└──────────────────┘",
+        ]),
+    );
+}
diff --git a/helix-tui/tests/widgets_table.rs b/helix-tui/tests/widgets_table.rs
new file mode 100644
index 00000000..0e0b3003
--- /dev/null
+++ b/helix-tui/tests/widgets_table.rs
@@ -0,0 +1,717 @@
+use helix_tui::{
+    backend::TestBackend,
+    buffer::Buffer,
+    layout::Constraint,
+    style::{Color, Modifier, Style},
+    text::{Span, Spans},
+    widgets::{Block, Borders, Cell, Row, Table, TableState},
+    Terminal,
+};
+
+#[test]
+fn widgets_table_column_spacing_can_be_changed() {
+    let test_case = |column_spacing, expected| {
+        let backend = TestBackend::new(30, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let table = Table::new(vec![
+                    Row::new(vec!["Row11", "Row12", "Row13"]),
+                    Row::new(vec!["Row21", "Row22", "Row23"]),
+                    Row::new(vec!["Row31", "Row32", "Row33"]),
+                    Row::new(vec!["Row41", "Row42", "Row43"]),
+                ])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+                .block(Block::default().borders(Borders::ALL))
+                .widths(&[
+                    Constraint::Length(5),
+                    Constraint::Length(5),
+                    Constraint::Length(5),
+                ])
+                .column_spacing(column_spacing);
+                f.render_widget(table, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    // no space between columns
+    test_case(
+        0,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1Head2Head3             │",
+            "│                            │",
+            "│Row11Row12Row13             │",
+            "│Row21Row22Row23             │",
+            "│Row31Row32Row33             │",
+            "│Row41Row42Row43             │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // one space between columns
+    test_case(
+        1,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1 Head2 Head3           │",
+            "│                            │",
+            "│Row11 Row12 Row13           │",
+            "│Row21 Row22 Row23           │",
+            "│Row31 Row32 Row33           │",
+            "│Row41 Row42 Row43           │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // enough space to just not hide the third column
+    test_case(
+        6,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1      Head2      Head3 │",
+            "│                            │",
+            "│Row11      Row12      Row13 │",
+            "│Row21      Row22      Row23 │",
+            "│Row31      Row32      Row33 │",
+            "│Row41      Row42      Row43 │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // enough space to hide part of the third column
+    test_case(
+        7,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1       Head2       Head│",
+            "│                            │",
+            "│Row11       Row12       Row1│",
+            "│Row21       Row22       Row2│",
+            "│Row31       Row32       Row3│",
+            "│Row41       Row42       Row4│",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_table_columns_widths_can_use_fixed_length_constraints() {
+    let test_case = |widths, expected| {
+        let backend = TestBackend::new(30, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let table = Table::new(vec![
+                    Row::new(vec!["Row11", "Row12", "Row13"]),
+                    Row::new(vec!["Row21", "Row22", "Row23"]),
+                    Row::new(vec!["Row31", "Row32", "Row33"]),
+                    Row::new(vec!["Row41", "Row42", "Row43"]),
+                ])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+                .block(Block::default().borders(Borders::ALL))
+                .widths(widths);
+                f.render_widget(table, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    // columns of zero width show nothing
+    test_case(
+        &[
+            Constraint::Length(0),
+            Constraint::Length(0),
+            Constraint::Length(0),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of 1 width trim
+    test_case(
+        &[
+            Constraint::Length(1),
+            Constraint::Length(1),
+            Constraint::Length(1),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│H H H                       │",
+            "│                            │",
+            "│R R R                       │",
+            "│R R R                       │",
+            "│R R R                       │",
+            "│R R R                       │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of large width just before pushing a column off
+    test_case(
+        &[
+            Constraint::Length(8),
+            Constraint::Length(8),
+            Constraint::Length(8),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1    Head2    Head3     │",
+            "│                            │",
+            "│Row11    Row12    Row13     │",
+            "│Row21    Row22    Row23     │",
+            "│Row31    Row32    Row33     │",
+            "│Row41    Row42    Row43     │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_table_columns_widths_can_use_percentage_constraints() {
+    let test_case = |widths, expected| {
+        let backend = TestBackend::new(30, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let table = Table::new(vec![
+                    Row::new(vec!["Row11", "Row12", "Row13"]),
+                    Row::new(vec!["Row21", "Row22", "Row23"]),
+                    Row::new(vec!["Row31", "Row32", "Row33"]),
+                    Row::new(vec!["Row41", "Row42", "Row43"]),
+                ])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+                .block(Block::default().borders(Borders::ALL))
+                .widths(widths)
+                .column_spacing(0);
+                f.render_widget(table, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    // columns of zero width show nothing
+    test_case(
+        &[
+            Constraint::Percentage(0),
+            Constraint::Percentage(0),
+            Constraint::Percentage(0),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of not enough width trims the data
+    test_case(
+        &[
+            Constraint::Percentage(11),
+            Constraint::Percentage(11),
+            Constraint::Percentage(11),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│HeaHeaHea                   │",
+            "│                            │",
+            "│RowRowRow                   │",
+            "│RowRowRow                   │",
+            "│RowRowRow                   │",
+            "│RowRowRow                   │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of large width just before pushing a column off
+    test_case(
+        &[
+            Constraint::Percentage(33),
+            Constraint::Percentage(33),
+            Constraint::Percentage(33),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1    Head2    Head3     │",
+            "│                            │",
+            "│Row11    Row12    Row13     │",
+            "│Row21    Row22    Row23     │",
+            "│Row31    Row32    Row33     │",
+            "│Row41    Row42    Row43     │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // percentages summing to 100 should give equal widths
+    test_case(
+        &[Constraint::Percentage(50), Constraint::Percentage(50)],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1         Head2         │",
+            "│                            │",
+            "│Row11         Row12         │",
+            "│Row21         Row22         │",
+            "│Row31         Row32         │",
+            "│Row41         Row42         │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_table_columns_widths_can_use_mixed_constraints() {
+    let test_case = |widths, expected| {
+        let backend = TestBackend::new(30, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let table = Table::new(vec![
+                    Row::new(vec!["Row11", "Row12", "Row13"]),
+                    Row::new(vec!["Row21", "Row22", "Row23"]),
+                    Row::new(vec!["Row31", "Row32", "Row33"]),
+                    Row::new(vec!["Row41", "Row42", "Row43"]),
+                ])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+                .block(Block::default().borders(Borders::ALL))
+                .widths(widths);
+                f.render_widget(table, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    // columns of zero width show nothing
+    test_case(
+        &[
+            Constraint::Percentage(0),
+            Constraint::Length(0),
+            Constraint::Percentage(0),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of not enough width trims the data
+    test_case(
+        &[
+            Constraint::Percentage(11),
+            Constraint::Length(20),
+            Constraint::Percentage(11),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Hea Head2                Hea│",
+            "│                            │",
+            "│Row Row12                Row│",
+            "│Row Row22                Row│",
+            "│Row Row32                Row│",
+            "│Row Row42                Row│",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of large width just before pushing a column off
+    test_case(
+        &[
+            Constraint::Percentage(33),
+            Constraint::Length(10),
+            Constraint::Percentage(33),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1     Head2      Head3  │",
+            "│                            │",
+            "│Row11     Row12      Row13  │",
+            "│Row21     Row22      Row23  │",
+            "│Row31     Row32      Row33  │",
+            "│Row41     Row42      Row43  │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of large size (>100% total) hide the last column
+    test_case(
+        &[
+            Constraint::Percentage(60),
+            Constraint::Length(10),
+            Constraint::Percentage(60),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1            Head2      │",
+            "│                            │",
+            "│Row11            Row12      │",
+            "│Row21            Row22      │",
+            "│Row31            Row32      │",
+            "│Row41            Row42      │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_table_columns_widths_can_use_ratio_constraints() {
+    let test_case = |widths, expected| {
+        let backend = TestBackend::new(30, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let table = Table::new(vec![
+                    Row::new(vec!["Row11", "Row12", "Row13"]),
+                    Row::new(vec!["Row21", "Row22", "Row23"]),
+                    Row::new(vec!["Row31", "Row32", "Row33"]),
+                    Row::new(vec!["Row41", "Row42", "Row43"]),
+                ])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+                .block(Block::default().borders(Borders::ALL))
+                .widths(widths)
+                .column_spacing(0);
+                f.render_widget(table, size);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    // columns of zero width show nothing
+    test_case(
+        &[
+            Constraint::Ratio(0, 1),
+            Constraint::Ratio(0, 1),
+            Constraint::Ratio(0, 1),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of not enough width trims the data
+    test_case(
+        &[
+            Constraint::Ratio(1, 9),
+            Constraint::Ratio(1, 9),
+            Constraint::Ratio(1, 9),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│HeaHeaHea                   │",
+            "│                            │",
+            "│RowRowRow                   │",
+            "│RowRowRow                   │",
+            "│RowRowRow                   │",
+            "│RowRowRow                   │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // columns of large width just before pushing a column off
+    test_case(
+        &[
+            Constraint::Ratio(1, 3),
+            Constraint::Ratio(1, 3),
+            Constraint::Ratio(1, 3),
+        ],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1    Head2    Head3     │",
+            "│                            │",
+            "│Row11    Row12    Row13     │",
+            "│Row21    Row22    Row23     │",
+            "│Row31    Row32    Row33     │",
+            "│Row41    Row42    Row43     │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // percentages summing to 100 should give equal widths
+    test_case(
+        &[Constraint::Ratio(1, 2), Constraint::Ratio(1, 2)],
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1         Head2         │",
+            "│                            │",
+            "│Row11         Row12         │",
+            "│Row21         Row22         │",
+            "│Row31         Row32         │",
+            "│Row41         Row42         │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_table_can_have_rows_with_multi_lines() {
+    let test_case = |state: &mut TableState, expected: Buffer| {
+        let backend = TestBackend::new(30, 8);
+        let mut terminal = Terminal::new(backend).unwrap();
+        terminal
+            .draw(|f| {
+                let size = f.size();
+                let table = Table::new(vec![
+                    Row::new(vec!["Row11", "Row12", "Row13"]),
+                    Row::new(vec!["Row21", "Row22", "Row23"]).height(2),
+                    Row::new(vec!["Row31", "Row32", "Row33"]),
+                    Row::new(vec!["Row41", "Row42", "Row43"]).height(2),
+                ])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+                .block(Block::default().borders(Borders::ALL))
+                .highlight_symbol(">> ")
+                .widths(&[
+                    Constraint::Length(5),
+                    Constraint::Length(5),
+                    Constraint::Length(5),
+                ])
+                .column_spacing(1);
+                f.render_stateful_widget(table, size, state);
+            })
+            .unwrap();
+        terminal.backend().assert_buffer(&expected);
+    };
+
+    let mut state = TableState::default();
+    // no selection
+    test_case(
+        &mut state,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│Head1 Head2 Head3           │",
+            "│                            │",
+            "│Row11 Row12 Row13           │",
+            "│Row21 Row22 Row23           │",
+            "│                            │",
+            "│Row31 Row32 Row33           │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // select first
+    state.select(Some(0));
+    test_case(
+        &mut state,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│   Head1 Head2 Head3        │",
+            "│                            │",
+            "│>> Row11 Row12 Row13        │",
+            "│   Row21 Row22 Row23        │",
+            "│                            │",
+            "│   Row31 Row32 Row33        │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // select second (we don't show partially the 4th row)
+    state.select(Some(1));
+    test_case(
+        &mut state,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│   Head1 Head2 Head3        │",
+            "│                            │",
+            "│   Row11 Row12 Row13        │",
+            "│>> Row21 Row22 Row23        │",
+            "│                            │",
+            "│   Row31 Row32 Row33        │",
+            "└────────────────────────────┘",
+        ]),
+    );
+
+    // select 4th (we don't show partially the 1st row)
+    state.select(Some(3));
+    test_case(
+        &mut state,
+        Buffer::with_lines(vec![
+            "┌────────────────────────────┐",
+            "│   Head1 Head2 Head3        │",
+            "│                            │",
+            "│   Row31 Row32 Row33        │",
+            "│>> Row41 Row42 Row43        │",
+            "│                            │",
+            "│                            │",
+            "└────────────────────────────┘",
+        ]),
+    );
+}
+
+#[test]
+fn widgets_table_can_have_elements_styled_individually() {
+    let backend = TestBackend::new(30, 4);
+    let mut terminal = Terminal::new(backend).unwrap();
+    let mut state = TableState::default();
+    state.select(Some(0));
+    terminal
+        .draw(|f| {
+            let size = f.size();
+            let table = Table::new(vec![
+                Row::new(vec!["Row11", "Row12", "Row13"]).style(Style::default().fg(Color::Green)),
+                Row::new(vec![
+                    Cell::from("Row21"),
+                    Cell::from("Row22").style(Style::default().fg(Color::Yellow)),
+                    Cell::from(Spans::from(vec![
+                        Span::raw("Row"),
+                        Span::styled("23", Style::default().fg(Color::Blue)),
+                    ]))
+                    .style(Style::default().fg(Color::Red)),
+                ])
+                .style(Style::default().fg(Color::LightGreen)),
+            ])
+            .header(Row::new(vec!["Head1", "Head2", "Head3"]).bottom_margin(1))
+            .block(Block::default().borders(Borders::LEFT | Borders::RIGHT))
+            .highlight_symbol(">> ")
+            .highlight_style(Style::default().add_modifier(Modifier::BOLD))
+            .widths(&[
+                Constraint::Length(6),
+                Constraint::Length(6),
+                Constraint::Length(6),
+            ])
+            .column_spacing(1);
+            f.render_stateful_widget(table, size, &mut state);
+        })
+        .unwrap();
+
+    let mut expected = Buffer::with_lines(vec![
+        "│   Head1  Head2  Head3      │",
+        "│                            │",
+        "│>> Row11  Row12  Row13      │",
+        "│   Row21  Row22  Row23      │",
+    ]);
+    // First row = row color + highlight style
+    for col in 1..=28 {
+        expected.get_mut(col, 2).set_style(
+            Style::default()
+                .fg(Color::Green)
+                .add_modifier(Modifier::BOLD),
+        );
+    }
+    // Second row:
+    // 1. row color
+    for col in 1..=28 {
+        expected
+            .get_mut(col, 3)
+            .set_style(Style::default().fg(Color::LightGreen));
+    }
+    // 2. cell color
+    for col in 11..=16 {
+        expected
+            .get_mut(col, 3)
+            .set_style(Style::default().fg(Color::Yellow));
+    }
+    for col in 18..=23 {
+        expected
+            .get_mut(col, 3)
+            .set_style(Style::default().fg(Color::Red));
+    }
+    // 3. text color
+    for col in 21..=22 {
+        expected
+            .get_mut(col, 3)
+            .set_style(Style::default().fg(Color::Blue));
+    }
+    terminal.backend().assert_buffer(&expected);
+}
+
+#[test]
+fn widgets_table_should_render_even_if_empty() {
+    let backend = TestBackend::new(30, 4);
+    let mut terminal = Terminal::new(backend).unwrap();
+    terminal
+        .draw(|f| {
+            let size = f.size();
+            let table = Table::new(vec![])
+                .header(Row::new(vec!["Head1", "Head2", "Head3"]))
+                .block(Block::default().borders(Borders::LEFT | Borders::RIGHT))
+                .widths(&[
+                    Constraint::Length(6),
+                    Constraint::Length(6),
+                    Constraint::Length(6),
+                ])
+                .column_spacing(1);
+            f.render_widget(table, size);
+        })
+        .unwrap();
+
+    let expected = Buffer::with_lines(vec![
+        "│Head1  Head2  Head3         │",
+        "│                            │",
+        "│                            │",
+        "│                            │",
+    ]);
+
+    terminal.backend().assert_buffer(&expected);
+}