add test for harmless disease

src/population.rs

@@ -15,6 +15,7 @@ pub struct Population {
     pub height: i32,
     pub age: i32,
     pub plague: Disease,
+    pub size: usize,
 }
 
 pub fn human_idx(x: i32, y: i32, width: i32) -> usize {
@@ -32,28 +33,30 @@ impl Population {
     ) -> Self {
         let mut rng = rand::thread_rng();
 
+        let size: usize = (width * height) as usize;
+
         let mut the_humans: Vec<Human> = vec![
             Human {
                 x: 0,
                 y: 0,
                 present_state: State::Normal
             };
-            (width * height) as usize
+            size
         ];
         for x in 0..width {
             for y in 0..height {
                 let idx = human_idx(x, y, width);
                 let mut present_state = State::Normal;
-                if (start_infected_ratio) > 0
+                if (start_infected_ratio > 0)
-                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_infected_ratio as i32)
+                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_infected_ratio)
                 {
                     present_state = State::Infected;
-                } else if start_immune_ratio > 0
+                } else if (start_immune_ratio > 0)
-                    && rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_immune_ratio as i32
+                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_immune_ratio)
                 {
                     present_state = State::Immune;
-                } else if start_dead_ratio > 0
+                } else if (start_dead_ratio > 0)
-                    && rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_dead_ratio as i32
+                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_dead_ratio)
                 {
                     present_state = State::Dead;
                 }
@@ -69,6 +72,7 @@ impl Population {
             plague: plague,
             age: 0,
             humans: the_humans,
+            size: size,
         }
     }
     // pub fn change_disease(&mut self, plague:Disease){
@@ -98,15 +102,15 @@ impl Population {
 
     pub fn propagate(&mut self) -> [i32; 4] {
         let mut people_to_check: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
+            Vec::with_capacity(self.size);
         let mut possible_infected: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
+            Vec::with_capacity(self.size);
         let mut people_to_infect: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
+            Vec::with_capacity(self.size);
         let mut people_to_cure: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
+            Vec::with_capacity(self.size);
         let mut people_to_kill: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
+            Vec::with_capacity(self.size);
         let mut stats: [i32; 4] = [0, 0, 0, 0];
         // stats[0] Normal stats[1] Infected stats[2] Immune stats[3] Dead
 
@@ -233,7 +237,7 @@ impl Population {
         }
         assert_eq!(
             stats[0] + stats[1] + stats[2] + stats[3],
-            self.humans.len() as i32
+            self.size as i32
         );
         stats
     }
@@ -639,6 +643,27 @@ mod tests {
         }
     }
 
+    #[parameterized(infection_start = {0, 50, 100})]
+    fn propagate_harmless(infection_start: i32) {
+        let disease: Disease = Disease::new(0, 0, 0, String::from("Harmless"));
+        let (width, height) = (100, 100);
+        let mut population: Population = Population::new(infection_start, 0, 0, width, height, disease);
+        let stats_before: Stats;
+        let stats_after: Stats;
+
+        stats_before = humans_stats(&population.humans);
+        let should_be_infected = population.size as i32 * infection_start / 100;
+        let tolerance = (should_be_infected as f32 * 0.20) as i32;
+        println!("{:?}", stats_before);
+        assert!(stats_before.infected <= should_be_infected + tolerance, "{} infected, should be less than {}", stats_before.infected, should_be_infected + tolerance);
+        assert!(stats_before.infected >= should_be_infected - tolerance, "{} infected, should be more than {}", stats_before.infected, should_be_infected - tolerance);
+
+        population.propagate();
+
+        stats_after = humans_stats(&population.humans);
+        assert_eq!(stats_before.infected, stats_after.infected, "no one should have been infected");
+    }
+
     #[parameterized(infection_rate = {0, 100, 0}, death_rate = {0, 0, 100}, infected_expected = {0, 1, 0})]
     fn propagate_test(infection_rate: i32, death_rate: i32, infected_expected: i32) {
         let disease: Disease;