remove dead code

src/disease.rs

@@ -5,14 +5,14 @@
 
 // #[derive(Debug)]
 pub struct Disease {
-    pub infection_rate: u32,
+    pub infection_rate: i32,
-    pub curing_rate: u32,
+    pub curing_rate: i32,
-    pub death_rate: u32,
+    pub death_rate: i32,
-    pub traits: Vec<u32>,
+    pub traits: Vec<i32>,
     pub name: String,
 }
 impl Disease {
-    pub fn new(infection_r: u32, curing_r: u32, death_r: u32, the_name: String) -> Self {
+    pub fn new(infection_r: i32, curing_r: i32, death_r: i32, the_name: String) -> Self {
         Self {
             infection_rate: infection_r,
             curing_rate: curing_r,

src/human.rs

@@ -1,33 +1,33 @@
 // use crate::prelude::*;
 
 // #[derive(Copy, Clone, PartialEq)]
-#[derive(PartialEq)]
+#[derive(PartialEq, Debug, Clone)]
 pub enum State {
     Normal,
     Infected,
     Dead,
     Immune,
 }
-// #[derive(Clone)]
+#[derive(Clone)]
 pub struct Human {
     pub present_state: State,
     pub x: i32,
     pub y: i32,
 }
-impl Human {
+// impl Human {
-    // humans with state "Normal"
+//     // humans with state "Normal"
-    pub fn new(pos_x: i32, pos_y: i32) -> Self {
+//     pub fn new(pos_x: i32, pos_y: i32) -> Self {
-        Self {
-            present_state: State::Normal,
-            x: pos_x,
-            y: pos_y,
-        }
-    }
-    // pub fn new_empty() -> Self{
 //         Self {
 //             present_state: State::Normal,
-    //         x : 0,
+//             x: pos_x,
-    //         y : 0,
+//             y: pos_y,
 //         }
 //     }
-}
+//     // pub fn new_empty() -> Self{
+//     //     Self{
+//     //         present_state:State::Normal,
+//     //         x : 0,
+//     //         y : 0,
+//     //     }
+//     // }
+// }

src/main.rs

@@ -17,28 +17,23 @@ fn main() {
     let term = Term::stdout();
     term.write_line("********** Rusty Propagation (Console) 2022 **********")
         .expect("Oops Looks like we have a problem here...");
-    term.write_line("Press any key to start the propagation")
-        .expect("Oops Looks like we have a problem here...");
 
     let disease = Disease::new(20, 10, 5, String::from("Covid 44"));
-    let mut population = Population::new(20, 10, 5, 300, 300, disease);
+    let mut population = Population::new(20, 10, 5, 1000, 1000, disease);
     //population.change_disease(disease);
-    println!("Before Filling");
-    //population.display();
-    population.generate();
     println!("After Filling");
     //population.display();
-    println!("After Propagation");
+    //population.display();
     let mut stats: [i32; 4];
     // = [0,0,0,0];
     let mut counter: u32 = 0;
     loop {
         counter += 1;
-        stats = population.propagate();
+        stats = population.propagate_new();
         //population.display();
         println!(
-            "Infecteds: {} Immunes: {} Deads: {}",
+            "Normal: {} Infecteds: {} Immunes: {} Deads: {}",
-            stats[1], stats[2], stats[3]
+            stats[0], stats[1], stats[2], stats[3]
         );
         if stats[1] == 0 {
             break;

src/population.rs

@@ -1,11 +1,168 @@
 use crate::prelude::*;
 
-// #[derive(Debug)]
+pub struct Population {
-pub struct Point {
+    pub start_infected_ratio: i32,
-    x: i32,
+    pub start_immune_ratio: i32,
-    y: i32,
+    pub start_dead_ratio: i32,
+    pub humans: Vec<Human>,
+    pub width: i32,
+    pub height: i32,
+    pub age: i32,
+    pub plague: Disease,
+    pub size: usize,
 }
 
+pub fn human_idx(x: i32, y: i32, width: i32) -> usize {
+    ((y * width) + x) as usize
+}
+
+impl Population {
+    pub fn new(
+        start_infected_ratio: i32,
+        start_immune_ratio: i32,
+        start_dead_ratio: i32,
+        width: i32,
+        height: i32,
+        plague: Disease,
+    ) -> 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
+            };
+            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)
+                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_infected_ratio)
+                {
+                    present_state = State::Infected;
+                } else if (start_immune_ratio > 0)
+                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_immune_ratio)
+                {
+                    present_state = State::Immune;
+                } else if (start_dead_ratio > 0)
+                    && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= start_dead_ratio)
+                {
+                    present_state = State::Dead;
+                }
+                the_humans[idx] = Human{x: x, y: y, present_state: present_state};
+            }
+        }
+        Self {
+            start_infected_ratio: start_infected_ratio,
+            start_immune_ratio: start_immune_ratio,
+            start_dead_ratio: start_dead_ratio,
+            width: width,
+            height: height,
+            plague: plague,
+            age: 0,
+            humans: the_humans,
+            size: size,
+        }
+    }
+
+    pub fn propagate_new(&mut self) -> [i32; 4] {
+        let mut stats: [i32; 4] = [0, 0, 0, 0];
+        let mut humans_n_plus_1: Vec<Human> = Vec::with_capacity(self.humans.len());
+
+        for human in self.humans.iter() {
+            let mut neighbors: Vec<&Human> = Vec::with_capacity(8);
+            if human.present_state == State::Normal {
+                let possible = [
+                    (human.x - 1, human.y - 1), (human.x, human.y - 1), (human.x + 1, human.y - 1),
+                    (human.x - 1, human.y)    ,                         (human.x + 1, human.y),
+                    (human.x - 1, human.y + 1), (human.x, human.y + 1), (human.x + 1, human.y + 1),
+                ];
+                for neigh_coords in possible.iter() {
+                    let neigh_idx = point_to_index(neigh_coords.0, neigh_coords.1, self.width, self.height);
+                    match neigh_idx {
+                        Some(x) => neighbors.push(&self.humans[x]),
+                        None => {},
+                    }
+                }
+            }
+            let new_human = evolve(human, neighbors, self.plague.infection_rate, self.plague.curing_rate, self.plague.death_rate);
+            match human.present_state {
+                State::Normal => { stats[0] += 1; }
+                State::Infected => { stats[1] += 1; }
+                State::Immune => { stats[2] += 1; }
+                State::Dead => { stats[3] += 1; }
+            }
+            humans_n_plus_1.push(new_human);
+        }
+
+        self.humans = humans_n_plus_1;
+        stats
+    }
+}
+
+fn evolve(human: &Human, neighbors: Vec<&Human>, infection_rate: i32, curing_rate: i32, death_rate: i32) -> Human {
+    let mut new_human = human.clone();
+    match human.present_state {
+        State::Normal => {
+            new_human.present_state = infect_by_neighbors(neighbors, infection_rate);
+        }
+        State::Infected => {
+            new_human.present_state = die_or_cure(curing_rate, death_rate);
+        }
+        State::Immune => {}
+        State::Dead => {}
+    }
+    new_human
+}
+
+fn infect_by_neighbors(neighbors: Vec<&Human>, infection_rate: i32) -> State {
+    for neighbor in neighbors.iter() {
+        if neighbor.present_state == State::Infected {
+            if roll(infection_rate) {
+                return State::Infected;
+            }
+        }
+    }
+    State::Normal
+}
+
+fn die_or_cure(curing_rate: i32, death_rate: i32) -> State {
+    if roll(curing_rate) {
+        State::Immune
+    } else if roll(death_rate) {
+        State::Dead
+    } else {
+        State::Infected
+    }
+}
+
+fn point_to_index(x: i32, y: i32, width: i32, height: i32) -> Option<usize> {
+    if (x >= 0) && (x < width) && (y >= 0) && (y < height) {
+        Some(human_idx(x, y, width))
+    } else {
+        None
+    }
+}
+
+pub fn roll(probability: i32) -> bool {
+    if probability > 0 {
+        let mut rng = rand::thread_rng();
+        rng.gen_range(0..CORRECTED_PERCENTAGE) <= probability
+    } else {
+        false
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use parameterized::parameterized;
+
     #[derive(Debug)]
     struct Stats {
         normal: i32,
@@ -25,21 +182,6 @@ impl Stats {
         }
     }
 
-pub struct Population {
-    pub start_infected_ratio: u32,
-    pub start_immune_ratio: u32,
-    pub start_dead_ratio: u32,
-    pub humans: Vec<Human>,
-    pub width: i32,
-    pub height: i32,
-    pub age: i32,
-    pub plague: Disease,
-}
-
-pub fn human_idx(x: i32, y: i32, width: i32) -> usize {
-    ((y * width) + x) as usize
-}
-
     fn humans_stats(humans: &Vec<Human>) -> Stats {
         let mut stats: Stats = Stats::new();
         for human in humans.iter() {
@@ -61,260 +203,6 @@ fn humans_stats(humans: &Vec<Human>) -> Stats {
         stats
     }
 
-
-impl Population {
-    pub fn new(
-        start_infected_ratio: u32,
-        start_immune_ratio: u32,
-        start_dead_ratio: u32,
-        width: i32,
-        height: i32,
-        plague: Disease,
-    ) -> Self {
-        let mut the_humans: Vec<Human> = Vec::with_capacity((width * height) as usize);
-        for x in 0..width {
-            for y in 0..height {
-                the_humans.push(Human::new(x, y));
-            }
-        }
-        Self {
-            start_infected_ratio: start_infected_ratio,
-            start_immune_ratio: start_immune_ratio,
-            start_dead_ratio: start_dead_ratio,
-            width: width,
-            height: height,
-            plague: plague,
-            age: 0,
-            humans: the_humans,
-        }
-    }
-    // pub fn change_disease(&mut self, plague:Disease){
-    //     self.plague = plague;
-    // }
-    pub fn generate(&mut self) {
-        //The ratios will not be exact, for example someone who wants 100% infected 100% immune and 100% dead, he will have 100% dead because they are overwriting each others
-        //Maybe consider limiting the total to not exceed 100 in the view
-        //Other thing, there will always be more of the last one because someone who is already infected for example could be then put to immune or dead
-        //One solution to this issue would be to have if else else statements but in this case for example 20% would be lower with the last because its 20% on the remaining population and not of the all
-        //In other words I did it that way but it can be changed just its not the right method to have perfect ratios
-        let mut rng = rand::thread_rng();
-
-        for x in self.humans.iter_mut() {
-            if (self.start_infected_ratio) > 0 && (rng.gen_range(0..CORRECTED_PERCENTAGE) <= self.start_infected_ratio as i32) {
-                x.present_state = State::Infected;
-            } else if self.start_immune_ratio > 0 && rng.gen_range(0..CORRECTED_PERCENTAGE) <= self.start_immune_ratio as i32 {
-                x.present_state = State::Immune;
-            } else if self.start_dead_ratio > 0 && rng.gen_range(0..CORRECTED_PERCENTAGE) <= self.start_dead_ratio as i32 {
-                x.present_state = State::Dead;
-            }
-        }
-    }
-
-    pub fn propagate(&mut self) -> [i32; 4] {
-        let mut people_to_check: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
-        let mut people_to_infect: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
-        let mut people_to_cure: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
-        let mut people_to_kill: Vec<Point> =
-            Vec::with_capacity((self.width * self.height) as usize);
-        let mut stats: [i32; 4] = [0, 0, 0, 0];
-        // stats[0] Normal stats[1] Infected stats[2] Immune stats[3] Dead
-
-        for h in self.humans.iter() {
-            match h.present_state {
-                State::Normal => {
-                    stats[0] += 1;
-                }
-                State::Infected => {
-                    people_to_check.push(Point { x: h.x, y: h.y });
-                    stats[1] += 1;
-                }
-                State::Immune => {
-                    stats[2] += 1;
-                }
-                State::Dead => {
-                    stats[3] += 1;
-                }
-            }
-        }
-        //        for pos in &people_to_check {
-        for pos in people_to_check.iter() {
-            //people_to_check.iter().map(|pos|{
-            //get all the other people next to me and check if i die cure or infect
-            //now we can start to check if people would be infected or not
-            //let idx = human_idx(pos.x as i32, pos.y as i32, self.width as i32);
-            if pos.x > 0 && pos.x < self.width - 1 && pos.y > 0 && pos.y < self.height - 1 {
-                if self.roll(self.plague.curing_rate) {
-                    //checks if the man dies
-                    people_to_cure.push(Point { x: pos.x, y: pos.y });
-                } else {
-                    if self.roll(self.plague.death_rate) {
-                        //cheks if the man dies
-                        people_to_kill.push(Point { x: pos.x, y: pos.y });
-                    } else {
-                        let mut possible_infections: Vec<Point> = Vec::with_capacity(8);
-                        // Vec::new();
-                        //possible_infections.push(Point{x:pos.x,y:pos.y});
-
-                        possible_infections.push(Point {
-                            x: pos.x - 1,
-                            y: pos.y - 1,
-                        }); //Top Left
-                        possible_infections.push(Point {
-                            x: pos.x,
-                            y: pos.y - 1,
-                        }); //Top
-                        possible_infections.push(Point {
-                            x: pos.x + 1,
-                            y: pos.y - 1,
-                        }); //Top Right
-
-                        possible_infections.push(Point {
-                            x: pos.x - 1,
-                            y: pos.y,
-                        }); //Left
-                        possible_infections.push(Point {
-                            x: pos.x + 1,
-                            y: pos.y,
-                        }); //Right
-
-                        possible_infections.push(Point {
-                            x: pos.x - 1,
-                            y: pos.y + 1,
-                        }); //Bottom Left
-                        possible_infections.push(Point {
-                            x: pos.x,
-                            y: pos.y + 1,
-                        }); //Bottom
-                        possible_infections.push(Point {
-                            x: pos.x + 1,
-                            y: pos.y + 1,
-                        }); //Bottom Right
-
-                        for poss_infected_pos in possible_infections.iter() {
-                            //possible_infections.iter().map(|poss_infected_pos|{
-                            let inf_idx =
-                                human_idx(poss_infected_pos.x, poss_infected_pos.y, self.width);
-                            if self.humans[inf_idx].present_state == State::Normal {
-                                if self.roll(self.plague.infection_rate) {
-                                    people_to_infect.push(Point {
-                                        x: poss_infected_pos.x,
-                                        y: poss_infected_pos.y,
-                                    });
-                                }
-                            }
-                        }
-                    }
-                }
-            } else {
-                //TODO
-                //Check every special cases (corners sides etc..)
-
-                //REMOVE WHEN IMPLEMENTED
-                //It is here to prevent an infected in the borders to keep the programm running as he thinks there are still people to simulate
-                people_to_kill.push(Point { x: pos.x, y: pos.y });
-
-                //    @##
-                //    ###
-                //    ###
-
-                //    #@#
-                //    ###
-                //    ###
-
-                //    ##@
-                //    ###
-                //    ###
-
-                //    ###
-                //    @##
-                //    ###
-
-                //    ###
-                //    ##@
-                //    ###
-
-                //    ###
-                //    ###
-                //    @##
-
-                //    ###
-                //    ###
-                //    #@#
-
-                //    ###
-                //    ###
-                //    ##@
-            }
-        }
-        println!(
-            "{} to infect, {} to cure, {} to kill",
-            people_to_infect.len(),
-            people_to_cure.len(),
-            people_to_kill.len()
-        );
-        for infected_position in &people_to_infect {
-            // println!("To infect: {:?}", infected_position);
-            //people_to_infect.iter().map(|infected_position|{
-            let infected_index = human_idx(infected_position.x, infected_position.y, self.width);
-            // let _ = infected_position.x;
-            //DEBUG
-            //println!("x: {} y: {} index: {}",infected_position.x,infected_position.y,infected_index);
-            self.humans[infected_index].present_state = State::Infected;
-            //DEBUG
-            //println!("Infected someone");
-        }
-
-        for cured_position in &people_to_cure {
-            //people_to_cure.iter().map(|cured_position|{
-            let cured_index = human_idx(cured_position.x, cured_position.y, self.width);
-            self.humans[cured_index].present_state = State::Immune;
-            //DEBUG
-            //println!("Cured someone");
-        }
-
-        for dead_position in &people_to_kill {
-            //people_to_kill.iter().map(|dead_position|{
-            let dead_index = human_idx(dead_position.x, dead_position.y, self.width);
-            if self.humans[dead_index].present_state == State::Dead {
-                println!("Already dead");
-            } else {
-                self.humans[dead_index].present_state = State::Dead;
-            }
-            //DEBUG
-        }
-        stats
-    }
-    pub fn roll(&self, probability: u32) -> bool {
-        let mut rng = rand::thread_rng();
-        rng.gen_range(0..CORRECTED_PERCENTAGE) <= probability as i32
-    }
-    // pub fn display(&mut self){
-    //     let sprite = "#";
-    //     print!("\n");
-    //     for x in 0..self.width{
-    //         for y in 0..self.height{
-    //             let index = human_idx(x as i32,y as i32,self.width as i32);
-    //             match self.humans[index].present_state {
-    //                 State::Normal => print!("{}",style(sprite).green()),
-    //                 State::Dead => print!("{}",style(sprite).black()),
-    //                 State::Infected => print!("{}",style(sprite).red()),
-    //                 State::Immune => print!("{}",style(sprite).blue()),
-    //                 _ => print!("{}",style(sprite).white()),
-    //             }
-    //         }
-    //         print!("\n");
-    //     }
-    // }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use parameterized::parameterized;
-
     #[parameterized(x = {
         2, 3, 5
     }, y = {
@@ -334,7 +222,11 @@ mod tests {
         let mut stats: Stats;
 
         for _ in 0..10 {
-            humans.push(Human::new(0, 0));
+            humans.push(Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 0,
+            });
         }
         stats = humans_stats(&humans);
         assert_eq!(stats.normal, 10);
@@ -358,20 +250,23 @@ mod tests {
     #[test]
     fn population_new() {
         let disease = Disease::new(20, 10, 5, String::from("Covid 44"));
+        let (width, height) = (5, 7);
         let population = Population::new(20, 10, 5, 5, 7, disease);
         assert_eq!(population.humans.len(), 5 * 7);
-        for human in population.humans.iter() {
+        for h in population.humans.iter() {
-            assert!(human.present_state == State::Normal, "all humans should be normal");
+            let idx = human_idx(h.x, h.y, width);
+            assert_eq!(population.humans[idx].x, h.x, "coordinates should match");
+            assert_eq!(population.humans[idx].y, h.y, "coordinates should match");
         }
+        assert_eq!(population.humans.len(), (width * height) as usize);
     }
 
     #[test]
     fn population_gen() {
         let disease = Disease::new(20, 10, 5, String::from("Covid 44"));
         let (width, height) = (5, 7);
-        let mut population = Population::new(20, 10, 5, 5, 7, disease);
+        let population = Population::new(20, 10, 5, 5, 7, disease);
 
-        population.generate();
         let stats: Stats = humans_stats(&population.humans);
         println!("Stats: {:?}", stats);
 
@@ -390,48 +285,323 @@ mod tests {
 
         disease = Disease::new(0, 0, 0, String::from("Test"));
         population = Population::new(0, 0, 0, width, height, disease);
-        population.generate();
         stats = humans_stats(&population.humans);
         println!("should be normal: {:?}", stats);
         assert_eq!(stats.normal, width * height);
 
         disease = Disease::new(0, 0, 0, String::from("Test"));
         population = Population::new(100, 0, 0, width, height, disease);
-        population.generate();
         stats = humans_stats(&population.humans);
         println!("should be infected: {:?}", stats);
         assert_eq!(stats.infected, width * height);
 
         disease = Disease::new(0, 0, 0, String::from("Test"));
         population = Population::new(0, 100, 0, width, height, disease);
-        population.generate();
         stats = humans_stats(&population.humans);
         println!("should be immune: {:?}", stats);
         assert_eq!(stats.immune, width * height);
 
         disease = Disease::new(0, 0, 0, String::from("Test"));
         population = Population::new(0, 0, 100, width, height, disease);
-        population.generate();
         stats = humans_stats(&population.humans);
         println!("should be dead: {:?}", stats);
         assert_eq!(stats.dead, width * height);
-
     }
 
-    #[parameterized(infection_rate = {0, 100}, infected_expected = {0, 1})]
+    #[parameterized(rate = {0, 100}, expected = {false, true})]
-    fn propage_test(infection_rate: u32, infected_expected: i32) {
+    fn roll_test(rate: i32, expected: bool) {
+        let tries = 100000;
+        let mut result = 0;
+        println!("Testing roll, rate {}, expected {}", rate, expected);
+        for _x in 0..tries {
+            if roll(rate) == expected {
+                result += 1;
+            }
+        }
+        assert_eq!(result, tries);
+    }
+
+    #[test]
+    fn propagate_simple() {
+        let disease: Disease = Disease::new(0, 0, 100, String::from("Deadly"));
+        let mut population: Population = Population::new(100, 0, 0, 10, 10, disease);
+        let mut stats: Stats;
+        let mut propagate_stats: [i32; 4];
+
+        // infect every one
+        stats = humans_stats(&population.humans);
+        println!("stats after init: {:?}", stats);
+        assert_eq!(stats.infected, 100, "everybody should be infected");
+
+        // kill every one
+        propagate_stats = population.propagate_new();
+        stats = humans_stats(&population.humans);
+        println!("propate_stats: {:?}", propagate_stats);
+        assert_eq!(propagate_stats, [0, 100, 0, 0]);
+        assert_eq!(stats.normal, 0);
+        assert_eq!(stats.infected, 0);
+        assert_eq!(stats.immune, 0);
+        assert_eq!(stats.dead, 100);
+
+        for _x in 0..100 {
+            propagate_stats = population.propagate_new();
+            stats = humans_stats(&population.humans);
+            println!("propate_stats: {:?}", propagate_stats);
+            assert_eq!(propagate_stats, [0, 0, 0, 100]);
+            assert_eq!(stats.normal, 0);
+            assert_eq!(stats.infected, 0);
+            assert_eq!(stats.immune, 0);
+            assert_eq!(stats.dead, 100);
+        }
+    }
+
+    #[test]
+    fn propagate_infect_all() {
+        let disease: Disease = Disease::new(100, 0, 0, String::from("Deadly"));
+        let mut population: Population = Population::new(0, 0, 0, 3, 3, disease);
+        let mut stats: Stats;
+        let mut propagate_stats: [i32; 4];
+
+        // start with normal population
+        population.humans = vec![
+            Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 0,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 1,
+                y: 0,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 2,
+                y: 0,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 1,
+            },
+            Human {
+                present_state: State::Infected,
+                x: 1,
+                y: 1,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 2,
+                y: 1,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 2,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 1,
+                y: 2,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 2,
+                y: 2,
+            },
+        ];
+        stats = humans_stats(&population.humans);
+        println!("stats after init: {:?}", stats);
+        assert_eq!(stats.normal, 8);
+
+        // kill every one
+        propagate_stats = population.propagate_new();
+        stats = humans_stats(&population.humans);
+        println!("propate_stats: {:?}", propagate_stats);
+        assert_eq!(propagate_stats, [8, 1, 0, 0]);
+        assert_eq!(stats.normal, 0);
+        assert_eq!(stats.infected, 9);
+        assert_eq!(stats.immune, 0);
+        assert_eq!(stats.dead, 0);
+
+        for _x in 0..100 {
+            propagate_stats = population.propagate_new();
+            stats = humans_stats(&population.humans);
+            println!("propate_stats: {:?}", propagate_stats);
+            assert_eq!(propagate_stats, [0, 9, 0, 0]);
+            assert_eq!(stats.normal, 0);
+            assert_eq!(stats.infected, 9);
+            assert_eq!(stats.immune, 0);
+            assert_eq!(stats.dead, 0);
+        }
+    }
+
+    #[test]
+    fn propagate_infect_cure_all() {
+        let disease: Disease = Disease::new(100, 100, 0, String::from("Deadly"));
+        let mut population: Population = Population::new(0, 0, 0, 3, 3, disease);
+        let mut stats: Stats;
+        let mut propagate_stats: [i32; 4];
+
+        // start with normal population
+        population.humans = vec![
+            Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 0,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 1,
+                y: 0,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 2,
+                y: 0,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 1,
+            },
+            Human {
+                present_state: State::Infected,
+                x: 1,
+                y: 1,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 2,
+                y: 1,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 2,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 1,
+                y: 2,
+            },
+            Human {
+                present_state: State::Normal,
+                x: 2,
+                y: 2,
+            },
+        ];
+        stats = humans_stats(&population.humans);
+        println!("stats after init: {:?}", stats);
+        assert_eq!(stats.normal, 8);
+
+        // infect every one
+        propagate_stats = population.propagate_new();
+        stats = humans_stats(&population.humans);
+        println!("propate_stats: {:?}", propagate_stats);
+        println!("population: {:?}", stats);
+        assert_eq!(propagate_stats, [8, 1, 0, 0]);
+        assert_eq!(stats.normal, 0);
+        assert_eq!(stats.infected, 8);
+        assert_eq!(stats.immune, 1);
+        assert_eq!(stats.dead, 0);
+
+        // cure every one
+        propagate_stats = population.propagate_new();
+        stats = humans_stats(&population.humans);
+        println!("propate_stats: {:?}", propagate_stats);
+        println!("population: {:?}", stats);
+        assert_eq!(propagate_stats, [0, 8, 1, 0]);
+        assert_eq!(stats.normal, 0);
+        assert_eq!(stats.infected, 0);
+        assert_eq!(stats.immune, 9);
+        assert_eq!(stats.dead, 0);
+
+        // then
+        for _x in 0..100 {
+            propagate_stats = population.propagate_new();
+            stats = humans_stats(&population.humans);
+            println!("propate_stats: {:?}", propagate_stats);
+            println!("population: {:?}", stats);
+            assert_eq!(propagate_stats, [0, 0, 9, 0]);
+            assert_eq!(stats.normal, 0);
+            assert_eq!(stats.infected, 0);
+            assert_eq!(stats.immune, 9);
+            assert_eq!(stats.dead, 0);
+        }
+    }
+
+    #[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_new();
+
+        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;
         let mut population: Population;
         let mut stats: Stats;
         let (width, height) = (100, 100);
+        let start_infected = 50;
+
+        println!(
+            "infection rate: {}, death_rate: {}",
+            infection_rate, death_rate
+        );
+
+        disease = Disease::new(infection_rate, 0, death_rate, String::from("Test"));
+        population = Population::new(start_infected, 0, 0, width, height, disease);
 
-        disease = Disease::new(infection_rate, 0, 0, String::from("Test"));
-        population = Population::new(50, 0, 0, width, height, disease);
         stats = humans_stats(&population.humans);
-        println!("Population: {:?}", stats);
+        println!("Population after init: {:?}", stats);
-        population.generate();
+
-        population.propagate();
+        // total * proba - 20% < infected < total * proba + 20%
+        let infected_at_start_proba = width * height * start_infected / 100;
+        let infected_tolerance = ((width * height) as f32 * 0.2) as i32;
+        assert!(stats.infected <= infected_at_start_proba + infected_tolerance);
+        assert!(stats.infected >= infected_at_start_proba - infected_tolerance);
+        assert_eq!(stats.dead, 0);
+
+        let infected_at_start = stats.infected;
+        let dead_at_start = stats.dead;
+
+        let propa_stats: [i32; 4] = population.propagate_new();
+
+        assert!(propa_stats[3] >= dead_at_start);
+
+        if death_rate == 0 {
+            assert_eq!(propa_stats[3], 0, "no human should have died");
+        }
+
         stats = humans_stats(&population.humans);
-        assert!(stats.normal <= width * height * infected_expected);
+        println!("Population after propagate: {:?}", stats);
+
+        assert!(stats.infected <= infected_at_start + width * height * infected_expected);
+
+        let should_be_dead = infected_at_start * death_rate / 100;
+        let dead_tolerance = (should_be_dead as f32 * 0.20) as i32;
+
+        assert!(
+            stats.dead <= should_be_dead + dead_tolerance,
+            "death count should be less or equal than {}",
+            should_be_dead + dead_tolerance
+        );
+        assert!(stats.dead >= should_be_dead - dead_tolerance);
     }
 }