Implemented delta-ing methods w/ unit tests.

gamelog/src/event.rs

@@ -57,13 +57,14 @@ impl Event {
                 unreachable!()
             };
 
-            Some((a - b) as i8)
+            Some(a as i8 - b as i8)
         }
     }
 }
 
-#[derive(Debug, Deserialize, Clone, PartialEq)]
+#[derive(Debug, Deserialize, Clone, PartialEq, Default)]
 pub enum ScorePoints {
+    #[default]
     Touchdown,
     FieldGoal,
     Safety,
@@ -86,3 +87,73 @@ impl ScorePoints {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::{Action, Down, Team, TerrainState};
+
+    #[test]
+    fn delta() {
+        let kickoff = Event::Kickoff(Team::Nebraska);
+        let first_down = Event::Play(Play {
+            action: Action::Unknown,
+            down: Some(Down::First),
+            terrain: Some(TerrainState::Yards(10)),
+        });
+        let second_down = Event::Play(Play {
+            action: Action::Unknown,
+            down: Some(Down::Second),
+            terrain: Some(TerrainState::Yards(10)),
+        });
+        let third_down = Event::Play(Play {
+            action: Action::Unknown,
+            down: Some(Down::Third),
+            terrain: Some(TerrainState::Yards(13)),
+        });
+        let fourth_down = Event::Play(Play {
+            action: Action::Unknown,
+            down: Some(Down::Fourth),
+            terrain: Some(TerrainState::Yards(5)),
+        });
+        let penalty = Event::Penalty(TerrainState::Yards(15));
+        let turnover = Event::Turnover(Team::Nebraska);
+        let noned_down = Event::Play(Play {
+            action: Action::Unknown,
+            down: None,
+            terrain: None,
+        });
+        let score = Event::Score(ScorePoints::default());
+        let goal_line = Event::Play(Play {
+            action: Action::Unknown,
+            down: Some(Down::First),
+            terrain: Some(TerrainState::GoalLine),
+        });
+        let inches = Event::Play(Play {
+            action: Action::Unknown,
+            down: Some(Down::First),
+            terrain: Some(TerrainState::Inches),
+        });
+
+        assert!(10_i8 == kickoff.delta(&first_down).unwrap());
+        assert!(0_i8 == first_down.delta(&second_down).unwrap());
+        assert!(-3_i8 == second_down.delta(&third_down).unwrap());
+        assert!(10_i8 == first_down.delta(&kickoff).unwrap());
+        assert!(10_i8 == first_down.delta(&goal_line).unwrap());
+        assert!(10_i8 == first_down.delta(&inches).unwrap());
+        assert!(13_i8 == third_down.delta(&kickoff).unwrap());
+        assert!(8_i8 == third_down.delta(&fourth_down).unwrap());
+        assert!(13_i8 == third_down.delta(&goal_line).unwrap());
+        assert!(None == fourth_down.delta(&turnover));
+        assert!(None == kickoff.delta(&penalty));
+        assert!(None == first_down.delta(&penalty));
+        assert!(None == noned_down.delta(&kickoff));
+        assert!(None == noned_down.delta(&turnover));
+        assert!(None == kickoff.delta(&score));
+        assert!(None == first_down.delta(&score));
+        assert!(None == turnover.delta(&score));
+        assert!(None == goal_line.delta(&first_down));
+        assert!(None == inches.delta(&first_down));
+        assert!(None == goal_line.delta(&inches));
+    }
+}