test(canvas): add tests for rectangle (#429)

src/widgets/canvas/rectangle.rs

@@ -50,3 +50,91 @@ impl Shape for Rectangle {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{
+        assert_buffer_eq,
+        prelude::*,
+        widgets::{canvas::Canvas, Widget},
+    };
+
+    #[test]
+    fn draw_block_lines() {
+        let mut buffer = Buffer::empty(Rect::new(0, 0, 10, 10));
+        let canvas = Canvas::default()
+            .marker(Marker::Block)
+            .x_bounds([0.0, 10.0])
+            .y_bounds([0.0, 10.0])
+            .paint(|context| {
+                context.draw(&Rectangle {
+                    x: 0.0,
+                    y: 0.0,
+                    width: 10.0,
+                    height: 10.0,
+                    color: Color::Red,
+                });
+            });
+        canvas.render(buffer.area, &mut buffer);
+        let mut expected = Buffer::with_lines(vec![
+            "██████████",
+            "█        █",
+            "█        █",
+            "█        █",
+            "█        █",
+            "█        █",
+            "█        █",
+            "█        █",
+            "█        █",
+            "██████████",
+        ]);
+        expected.set_style(buffer.area, Style::new().red());
+        expected.set_style(buffer.area.inner(&Margin::new(1, 1)), Style::reset());
+        assert_buffer_eq!(buffer, expected);
+    }
+
+    #[test]
+    fn draw_braille_lines() {
+        let mut buffer = Buffer::empty(Rect::new(0, 0, 10, 10));
+        let canvas = Canvas::default()
+            .marker(Marker::Braille)
+            .x_bounds([0.0, 10.0])
+            .y_bounds([0.0, 10.0])
+            .paint(|context| {
+                // a rectangle that will draw the outside part of the braille
+                context.draw(&Rectangle {
+                    x: 0.0,
+                    y: 0.0,
+                    width: 10.0,
+                    height: 10.0,
+                    color: Color::Red,
+                });
+                // a rectangle that will draw the inside part of the braille
+                context.draw(&Rectangle {
+                    x: 2.0,
+                    y: 1.75,
+                    width: 6.5,
+                    height: 6.5,
+                    color: Color::Green,
+                });
+            });
+        canvas.render(buffer.area, &mut buffer);
+        let mut expected = Buffer::with_lines(vec![
+            "⡏⠉⠉⠉⠉⠉⠉⠉⠉⢹",
+            "⡇⢠⠤⠤⠤⠤⠤⠤⡄⢸",
+            "⡇⢸      ⡇⢸",
+            "⡇⢸      ⡇⢸",
+            "⡇⢸      ⡇⢸",
+            "⡇⢸      ⡇⢸",
+            "⡇⢸      ⡇⢸",
+            "⡇⢸      ⡇⢸",
+            "⡇⠈⠉⠉⠉⠉⠉⠉⠁⢸",
+            "⣇⣀⣀⣀⣀⣀⣀⣀⣀⣸",
+        ]);
+        expected.set_style(buffer.area, Style::new().red());
+        expected.set_style(buffer.area.inner(&Margin::new(1, 1)), Style::new().green());
+        expected.set_style(buffer.area.inner(&Margin::new(2, 2)), Style::reset());
+        assert_buffer_eq!(buffer, expected);
+    }
+}