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use super::Polygon;
use crate::Point;
#[derive(Default, Debug)]
pub struct PolygonBuilder {
vertices: Vec<Point>,
}
impl PolygonBuilder {
pub fn vertex(mut self, x: f64, y: f64) -> Self {
self.vertices.push(Point { x, y });
self
}
pub fn build(self) -> Result<Polygon, ()> {
Polygon::try_new(self.vertices)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_polygon_builder_works() {
let polygon = PolygonBuilder::default()
.vertex(0.0, 0.0)
.vertex(0.0, 1.0)
.vertex(1.0, 0.0)
.vertex(1.0, 1.0)
.build()
.unwrap();
let expected = Polygon {
vertices: vec![
Point { x: 0.0, y: 0.0 },
Point { x: 0.0, y: 1.0 },
Point { x: 1.0, y: 0.0 },
Point { x: 1.0, y: 1.0 },
],
};
assert_eq!(expected, polygon);
}
#[test]
fn test_polygon_builder_errors_for_no_vertices() {
assert_eq!(Err(()), PolygonBuilder::default().build());
}
#[test]
fn test_polygon_builder_errors_for_one_vertex() {
assert_eq!(Err(()), PolygonBuilder::default().vertex(1.0, 1.0).build());
}
#[test]
fn test_polygon_builder_panicks_for_two_vertices() {
assert_eq!(
Err(()),
PolygonBuilder::default()
.vertex(0.0, 0.0)
.vertex(1.0, 1.0)
.build()
);
}
}