[librsvg] viewport.rs: Start adding tests

[Federico Mena Quintero <federico src gnome org>]

commit 01a4b0a2d4985c7dc25afcfac0709e9d5eefb439
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Sep 27 14:40:08 2017 -0500

    viewport.rs: Start adding tests

 rust/src/viewport.rs |  120 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 120 insertions(+), 0 deletions(-)
---
diff --git a/rust/src/viewport.rs b/rust/src/viewport.rs
index 0a56546..6a8cfc6 100644
--- a/rust/src/viewport.rs
+++ b/rust/src/viewport.rs
@@ -123,3 +123,123 @@ fn in_viewport<F>(ctx: &mut ViewportCtx,
     ctx.pop_discrete_layer();
     ctx.pop_view_box();
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use parsers::Parse;
+
+    #[derive(Default, PartialEq)]
+    struct Ctx {
+        pub view_box_size: Option<(f64, f64)>,
+        pub clipping_rect: Option<(f64, f64, f64, f64)>,
+        pub affine:        Option<cairo::Matrix>,
+
+        pub expected_view_box_size: Option<(f64, f64)>,
+        pub expected_clipping_rect: Option<(f64, f64, f64, f64)>,
+        pub expected_affine:        Option<cairo::Matrix>,
+    }
+
+    impl ViewportCtx for Ctx {
+        fn push_view_box(&mut self, width: f64, height: f64) {
+            self.view_box_size = Some((width, height));
+        }
+
+        fn pop_view_box(&mut self) {
+        }
+
+        fn push_discrete_layer(&mut self) {
+        }
+
+        fn pop_discrete_layer(&mut self) {
+        }
+
+        fn add_clipping_rect(&mut self, x: f64, y: f64, w: f64, h: f64) {
+            self.clipping_rect = Some((x, y, w, h));
+        }
+
+        fn set_affine(&mut self, affine: cairo::Matrix) {
+            self.affine = Some(affine);
+        }
+    }
+
+    fn call_in_viewport(vx: f64, vy: f64, vw: f64, vh: f64,
+                        clip_before_layer_push: bool,
+                        do_clip: bool,
+                        vbox: Option<ViewBox>,
+                        preserve_aspect_ratio: AspectRatio,
+                        affine: cairo::Matrix,
+                        ctx: &mut Ctx) {
+        in_viewport(ctx,
+                    vx, vy, vw, vh,
+                    clip_before_layer_push,
+                    do_clip,
+                    vbox,
+                    preserve_aspect_ratio,
+                    affine,
+                    || ());
+
+        assert_eq!(ctx.view_box_size, ctx.expected_view_box_size);
+        assert_eq!(ctx.clipping_rect, ctx.expected_clipping_rect);
+        assert_eq!(ctx.affine, ctx.expected_affine);
+    }
+
+    #[test]
+    fn clip_after_layer_push() {
+        let mut affine = cairo::Matrix::identity();
+        affine.scale(0.20, 0.20);
+
+        let mut ctx = Ctx {
+            view_box_size: None,
+            clipping_rect: None,
+            affine:        None,
+
+            expected_view_box_size: Some((50.0, 50.0)),
+            expected_clipping_rect: Some((10.0, 10.0, 10.0, 10.0)),
+            expected_affine: Some(affine)
+        };
+
+        call_in_viewport(10.0, 10.0, 10.0, 10.0,
+                         false,
+                         true,
+                         Some(ViewBox(cairo::Rectangle {
+                             x: 50.0,
+                             y: 50.0,
+                             width: 50.0,
+                             height: 50.0,
+                         })),
+                         AspectRatio::parse("xMidYMid meet", ()).unwrap(),
+                         cairo::Matrix::identity(),
+                         &mut ctx);
+    }
+
+    #[test]
+    fn clip_before_layer_push() {
+        let mut affine = cairo::Matrix::identity();
+        affine.translate(10.0, 10.0);
+        affine.scale(0.40, 0.40);
+
+        let mut ctx = Ctx {
+            view_box_size: None,
+            clipping_rect: None,
+            affine:        None,
+
+            expected_view_box_size: Some((50.0, 50.0)),
+            expected_clipping_rect: Some((0.0, 0.0, 50.0, 50.0)),
+            expected_affine: Some(affine)
+        };
+
+        call_in_viewport(10.0, 10.0, 20.0, 20.0,
+                         true,
+                         true,
+                         Some(ViewBox(cairo::Rectangle {
+                             x: 0.0,
+                             y: 0.0,
+                             width: 50.0,
+                             height: 50.0,
+                         })),
+                         AspectRatio::parse("xMidYMid meet", ()).unwrap(),
+                         cairo::Matrix::identity(),
+                         &mut ctx);
+    }
+}