improving tests for Offset trait

Author: thehappycheese

geo/src/algorithm/offset/cross_product.rs

@@ -69,7 +69,7 @@ mod test {
         // expect swapping will result in negative
         assert_eq!(cross_product_2d(ab, ac), -1f64);
 
-        // Add skew
+        // Add skew; results should be the same
         let a = Coord { x: 0f64, y: 0f64 };
         let b = Coord { x: 0f64, y: 1f64 };
         let c = Coord { x: 1f64, y: 1f64 };

geo/src/algorithm/offset/line_intersection.rs

@@ -213,7 +213,7 @@ mod test {
         FalseIntersectionPointType, LineIntersectionWithParameterResult,
         LineSegmentIntersectionType,
     };
-    use crate::Coord;
+    use crate::{Coord, coord};
     use FalseIntersectionPointType::{AfterEnd, BeforeStart};
     use LineSegmentIntersectionType::{FalseIntersectionPoint, TrueIntersectionPoint};
 
@@ -269,6 +269,12 @@ mod test {
         let b = Coord { x: 2f64, y: 3f64 };
         let c = Coord { x: 0f64, y: 2f64 };
         let d = Coord { x: -2f64, y: 6f64 };
+
+        fn check_intersection(intersection:Coord<f64>){
+            let diff = intersection - Coord { x: 1f64 / 3f64, y: 4f64 / 3f64 };
+            assert!(diff.x * diff.x + diff.y * diff.y < 0.00000000001f64);
+        }
+
         if let Some(LineIntersectionWithParameterResult {
             ab,
             cd,
@@ -277,14 +283,7 @@ mod test {
         {
             assert_eq!(ab, FalseIntersectionPoint(BeforeStart));
             assert_eq!(cd, FalseIntersectionPoint(BeforeStart));
-            println!("{intersection:?}");
-            let diff = intersection
-                - Coord {
-                    x: 1.0 / 3.0f64,
-                    y: 4.0 / 3.0f64,
-                };
-            println!("{diff:?}");
-            assert!(diff.x * diff.x + diff.y * diff.y < 0.00000000001f64);
+            check_intersection(intersection);
         } else {
             assert!(false);
         }
@@ -297,14 +296,7 @@ mod test {
         {
             assert_eq!(ab, FalseIntersectionPoint(AfterEnd));
             assert_eq!(cd, FalseIntersectionPoint(BeforeStart));
-            println!("{intersection:?}");
-            let diff = intersection
-                - Coord {
-                    x: 1.0 / 3.0f64,
-                    y: 4.0 / 3.0f64,
-                };
-            println!("{diff:?}");
-            assert!(diff.x * diff.x + diff.y * diff.y < 0.00000000001f64);
+            check_intersection(intersection);
         } else {
             assert!(false);
         }
@@ -317,14 +309,7 @@ mod test {
         {
             assert_eq!(ab, FalseIntersectionPoint(BeforeStart));
             assert_eq!(cd, FalseIntersectionPoint(AfterEnd));
-            println!("{intersection:?}");
-            let diff = intersection
-                - Coord {
-                    x: 1.0 / 3.0f64,
-                    y: 4.0 / 3.0f64,
-                };
-            println!("{diff:?}");
-            assert!(diff.x * diff.x + diff.y * diff.y < 0.00000000001f64);
+            check_intersection(intersection);
         } else {
             assert!(false);
         }

geo/src/algorithm/offset/offset_trait.rs

@@ -115,19 +115,28 @@ where
                         // we are potentially creating a redundant point in the
                         // output here. Colinear segments should maybe get
                         // removed before or after this algorithm
+                        //println!("CASE 0 - colinear");
                         vec![*b]
                     }, 
                     Some(LineIntersectionWithParameterResult {
                         ab,
                         cd,
                         intersection,
                     }) => match (ab, cd) {
-                        (TrueIntersectionPoint, TrueIntersectionPoint) => vec![intersection],
+                        (TrueIntersectionPoint, TrueIntersectionPoint) => {
+                            //println!("CASE 1 - extend");
+                            vec![intersection]
+                        },
                         (FalseIntersectionPoint(AfterEnd), FalseIntersectionPoint(_)) => {
                             // TODO: Mitre limit logic goes here
+                            //println!("CASE 2 - extend");
                             vec![intersection]
                         }
-                        _ => vec![*b, *c],
+                        _ => {
+                            println!("CASE 3 - bridge");
+                            vec![*b, *c]
+                        },
+
                     },
                 }
             },
@@ -282,7 +291,7 @@ mod test {
                 x: 5.279039119779313f64,
                 y: 2.516847170273373f64
             },
-            Coord { x: 5f64, y: 2f64 },
+            Coord { x: 5.20f64, y: 2.36f64 },
             Coord {
                 x: 3.2388869474813826f64,
                 y: 4.489952088082639f64