add cli option to specify number of threads

Cargo.lock

@@ -2,18 +2,74 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "winapi",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
 
+[[package]]
+name = "bitflags"
+version = "1.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "clap"
+version = "3.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85a35a599b11c089a7f49105658d089b8f2cf0882993c17daf6de15285c2c35d"
+dependencies = [
+ "atty",
+ "bitflags",
+ "clap_derive",
+ "clap_lex",
+ "indexmap",
+ "lazy_static",
+ "strsim",
+ "termcolor",
+ "textwrap",
+]
+
+[[package]]
+name = "clap_derive"
+version = "3.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3aab4734e083b809aaf5794e14e756d1c798d2c69c7f7de7a09a2f5214993c1"
+dependencies = [
+ "heck",
+ "proc-macro-error",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a37c35f1112dad5e6e0b1adaff798507497a18fceeb30cceb3bae7d1427b9213"
+dependencies = [
+ "os_str_bytes",
+]
+
 [[package]]
 name = "console"
 version = "0.15.0"
@@ -52,6 +108,21 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d7afe4a420e3fe79967a00898cc1f4db7c8a49a9333a29f8a4bd76a253d5cd04"
 
+[[package]]
+name = "heck"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
+
+[[package]]
+name = "hermit-abi"
+version = "0.1.19"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "62b467343b94ba476dcb2500d242dadbb39557df889310ac77c5d99100aaac33"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "indexmap"
 version = "1.6.2"
@@ -62,6 +133,12 @@ dependencies = [
  "hashbrown",
 ]
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.124"
@@ -74,6 +151,12 @@ version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "87f3e037eac156d1775da914196f0f37741a274155e34a0b7e427c35d2a2ecb9"
 
+[[package]]
+name = "os_str_bytes"
+version = "6.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8e22443d1643a904602595ba1cd8f7d896afe56d26712531c5ff73a15b2fbf64"
+
 [[package]]
 name = "parameterized"
 version = "1.0.0"
@@ -101,6 +184,30 @@ version = "0.2.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "eb9f9e6e233e5c4a35559a617bf40a4ec447db2e84c20b55a6f83167b7e57872"
 
+[[package]]
+name = "proc-macro-error"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "version_check",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.37"
@@ -168,11 +275,18 @@ checksum = "f497285884f3fcff424ffc933e56d7cbca511def0c9831a7f9b5f6153e3cc89b"
 name = "rusty_propagation"
 version = "0.1.0"
 dependencies = [
+ "clap",
  "console",
  "parameterized",
  "rand",
 ]
 
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
 [[package]]
 name = "syn"
 version = "1.0.92"
@@ -184,6 +298,15 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bab24d30b911b2376f3a13cc2cd443142f0c81dda04c118693e35b3835757755"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "terminal_size"
 version = "0.1.17"
@@ -194,6 +317,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "textwrap"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b1141d4d61095b28419e22cb0bbf02755f5e54e0526f97f1e3d1d160e60885fb"
+
 [[package]]
 name = "unicode-width"
 version = "0.1.9"
@@ -206,6 +335,12 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "957e51f3646910546462e67d5f7599b9e4fb8acdd304b087a6494730f9eebf04"
 
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"
@@ -228,6 +363,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"

Cargo.toml

@@ -7,3 +7,4 @@ edition = "2021"
 console = "0.15.0" 
 rand = "0.8.5" 
 parameterized = "1.0.0"
+clap = { version = "3.0", features = ["derive"] }

src/main.rs

@@ -1,3 +1,5 @@
+use clap::Parser;
+
 mod disease;
 mod human;
 mod population;
@@ -13,7 +15,14 @@ mod prelude {
 
 use prelude::*;
 
+#[derive(Parser)]
+struct Cli {
+    /// Number of threads to use
+    threads: usize,
+}
+
 fn main() {
+    let args = Cli::parse();
     let term = Term::stdout();
     term.write_line("********** Rusty Propagation (Console) 2022 **********")
         .expect("Oops Looks like we have a problem here...");
@@ -29,7 +38,7 @@ fn main() {
     let mut counter: u32 = 0;
     loop {
         counter += 1;
-        stats = population.propagate();
+        stats = population.propagate(args.threads);
         //population.display();
         println!(
             "Normal: {} Infecteds: {} Immunes: {} Deads: {}",

src/population.rs

@@ -1,4 +1,8 @@
+
+use std::sync::{Arc, RwLock};
 use crate::prelude::*;
+use std::thread;
+use std::time::{Instant};
 
 #[derive(Debug)]
 pub struct Point {
@@ -10,7 +14,7 @@ pub struct Population {
     pub start_infected_ratio: i32,
     pub start_immune_ratio: i32,
     pub start_dead_ratio: i32,
-    pub humans: Vec<Human>,
+    pub humans: Arc<RwLock<Vec<Human>>>,
     pub width: i32,
     pub height: i32,
     pub age: i32,
@@ -35,7 +39,7 @@ impl Population {
 
         let size: usize = (width * height) as usize;
 
-        let mut the_humans: Vec<Human> = vec![
+        let mut the_humans = vec![
             Human {
                 x: 0,
                 y: 0,
@@ -43,6 +47,7 @@ impl Population {
             };
             size
         ];
+
         for x in 0..width {
             for y in 0..height {
                 let idx = human_idx(x, y, width);
@@ -63,6 +68,7 @@ impl Population {
                 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,
@@ -71,7 +77,7 @@ impl Population {
             height: height,
             plague: plague,
             age: 0,
-            humans: the_humans,
+            humans: Arc::new(RwLock::new(the_humans)),
             size: size,
         }
     }
@@ -79,28 +85,31 @@ impl Population {
     //     self.plague = plague;
     // }
 
-    fn is_inside(&self, pos: &Point) -> bool {
+    // fn is_inside(&self, pos: &Point) -> bool {
-        if pos.x >= 0 && pos.x < self.width && pos.y >= 0 && pos.y < self.height {
+    //     if pos.x >= 0 && pos.x < self.width && pos.y >= 0 && pos.y < self.height {
-            true
+    //         true
-        } else {
+    //     } else {
-            false
+    //         false
-        }
+    //     }
-    }
+    // }
 
-    fn is_inside_and_infected(&self, point: Point) -> bool {
+    // fn is_inside_and_infected(&self, point: Point) -> bool {
-        if self.is_inside(&point) {
+    //     let humans = Arc::clone(&self.humans);
-            let idx = human_idx(point.x, point.y, self.width);
+    //     if self.is_inside(&point) {
-            if self.humans[idx].present_state == State::Infected {
+    //         let idx = human_idx(point.x, point.y, self.width);
-                roll(self.plague.infection_rate)
+    //         let humans = humans.read().unwrap();
-            } else {
+    //         if humans[idx].present_state == State::Infected {
-                false
+    //             roll(self.plague.infection_rate)
-            }
+    //         } else {
-        } else {
+    //             false
-            false
+    //         }
-        }
+    //     } else {
-    }
+    //         false
+    //     }
+    // }
 
-    pub fn propagate(&mut self) -> [i32; 4] {
+    pub fn propagate(&mut self, num_threads: usize) -> [i32; 4] {
+        let timer = Instant::now();
         let mut people_to_check: Vec<Point> =
             Vec::with_capacity(self.size);
         let mut possible_infected: Vec<Point> =
@@ -114,7 +123,29 @@ impl Population {
         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() {
+        let mut threads = vec![];
+
+        let len: usize = (self.width * self.height) as usize;
+        let mut lines = (len / num_threads) as usize;
+        if len % num_threads != 0 {
+            lines += 1;
+        }
+        for x in 0..num_threads {
+            let lower_bound = x * lines;
+            let mut upper_bound = (x + 1) * lines;
+            if upper_bound > len {
+                upper_bound = len;
+            };
+
+            let humans = Arc::clone(&self.humans);
+            threads.push(thread::spawn(move || {
+                let mut possible_infected: Vec<Point> =Vec::with_capacity(lines);
+                let mut people_to_check: Vec<Point> =Vec::with_capacity(lines);
+                let mut stats: [i32; 4] = [0, 0, 0, 0];
+                let humans = humans.read().unwrap();
+
+                for idx in lower_bound..upper_bound {
+                    let h = &humans[idx];
                     match h.present_state {
                         State::Normal => {
                             possible_infected.push(Point{ x: h.x, y: h.y});
@@ -132,113 +163,233 @@ impl Population {
                         }
                     }
                 }
-        //        for pos in &people_to_check {
+                (possible_infected, people_to_check, stats)
-        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
+        for t in threads {
-            //let idx = human_idx(pos.x as i32, pos.y as i32, self.width as i32);
+            let mut res = t.join().unwrap();
-            if roll(self.plague.curing_rate) {
+            possible_infected.append(&mut res.0);
+            people_to_check.append(&mut res.1);
+            for x in 0..4 {
+                stats[x] += res.2[x];
+            }
+        }
+
+        #[cfg(debug_assertions)]
+        println!("after first pass {:?}", timer.elapsed());
+
+        debug_assert_eq!(
+            stats[0] + stats[1] + stats[2] + stats[3],
+            self.size as i32
+        );
+
+
+        let mut threads = vec![];
+
+        let len: usize = people_to_check.len();
+        let mut lines = (len / num_threads) as usize;
+        if len % num_threads != 0 {
+            lines += 1;
+        }
+        let people_to_check_arc = Arc::new(people_to_check);
+        for x in 0..num_threads {
+            let lower_bound = x * lines;
+            let mut upper_bound = (x + 1) * lines;
+            if upper_bound > len {
+                upper_bound = len;
+            };
+            let curing_rate = self.plague.curing_rate;
+            let death_rate = self.plague.death_rate;
+            let people_to_check = Arc::clone(&people_to_check_arc);
+            threads.push(thread::spawn(move || {
+                let mut people_to_cure: Vec<Point> =Vec::with_capacity(lines);
+                let mut people_to_kill: Vec<Point> =Vec::with_capacity(lines);
+                for idx in lower_bound..upper_bound {
+                    let pos = &people_to_check[idx];
+                    if roll(curing_rate) {
                         //checks if the man recovers
                         people_to_cure.push(Point { x: pos.x, y: pos.y });
                     } else {
-                if roll(self.plague.death_rate) {
+                        if roll(death_rate) {
                             //cheks if the man dies
                             people_to_kill.push(Point { x: pos.x, y: pos.y });
                         }
                     }
                 }
-        for pos in possible_infected.iter() {
+                (people_to_cure, people_to_kill)
-            let infected: bool = self.is_inside_and_infected(
+            }));
+        }
+        for t in threads {
+            let mut res = t.join().unwrap();
+            people_to_cure.append(&mut res.0);
+            people_to_kill.append(&mut res.1);
+        }
+
+        #[cfg(debug_assertions)]
+        println!("after people_to_check {:?}", timer.elapsed());
+
+        // check normal people to see if someone near is infected
+
+        let mut threads = vec![];
+
+        let len: usize = possible_infected.len();
+        let mut lines = (len / num_threads) as usize;
+        if len % num_threads != 0 {
+            lines += 1;
+        }
+        let possible_infected_arc = Arc::new(possible_infected);
+
+        {
+            let (width, height) = (self.width, self.height);
+            let infection_rate = self.plague.infection_rate;
+
+            for x in 0..num_threads {
+                let humans = Arc::clone(&self.humans);
+
+
+                let lower_bound = x * lines;
+                let mut upper_bound = (x + 1) * lines;
+                if upper_bound > len {
+                    upper_bound = len;
+                };
+                let possible_infected = Arc::clone(&possible_infected_arc);
+                threads.push(thread::spawn(move || {
+                    let humans = &humans.read().unwrap().to_vec();
+                    let mut people_to_infect: Vec<Point> =Vec::with_capacity(lines);
+                    for idx in lower_bound..upper_bound {
+                        let pos = &possible_infected[idx];
+
+                        let infected: bool = fn_is_inside_and_infected(
                             Point {
                                 x: pos.x - 1,
                                 y: pos.y - 1,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Top Left
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x,
                                 y: pos.y - 1,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Top
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x + 1,
                                 y: pos.y - 1,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Top Right
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x - 1,
                                 y: pos.y,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Left
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x + 1,
                                 y: pos.y,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Right
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x - 1,
                                 y: pos.y + 1,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Bottom Left
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x,
                                 y: pos.y + 1,
-                },
+                            }, width, height, humans, infection_rate
                         ) || //Bottom
-            self.is_inside_and_infected(
+                        fn_is_inside_and_infected(
                             Point {
                                 x: pos.x + 1,
                                 y: pos.y + 1,
-                },
+                            }, width, height, humans, infection_rate
                         ); //Bottom Right
                         if infected {
                             people_to_infect.push(Point { x: pos.x, y: pos.y });
                         }
                     }
-
+                    people_to_infect
-        for infected_position in people_to_infect.iter() {
+                }));
-            // println!("To infect: {:?}", infected_position);
+            }
-            //people_to_infect.iter().map(|infected_position|{
+            for t in threads {
-            let infected_index = human_idx(infected_position.x, infected_position.y, self.width);
+                let mut res = t.join().unwrap();
-            // let _ = infected_position.x;
+                people_to_infect.append(&mut res);
-            //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");
         }
 
+        #[cfg(debug_assertions)]
+        println!("after possible_infected {:?}", timer.elapsed());
+
+        let mut threads = vec![];
+
+        {
+            let humans = Arc::clone(&self.humans);
+            let width = self.width;
+            threads.push(thread::spawn(move || {
+                for infected_position in people_to_infect.iter() {
+                    let infected_index = human_idx(infected_position.x, infected_position.y, width);
+                    {
+                        // eprint!("i");
+                        let mut humans = humans.write().unwrap();
+                        humans[infected_index].present_state = State::Infected;
+                    }
+                }
+            }));
+        }
+
+        {
+            let humans = Arc::clone(&self.humans);
+            let width = self.width;
+            threads.push(thread::spawn(move || {
                 for cured_position in people_to_cure.iter() {
                     //people_to_cure.iter().map(|cured_position|{
-            let cured_index = human_idx(cured_position.x, cured_position.y, self.width);
+                    let cured_index = human_idx(cured_position.x, cured_position.y, width);
-            if self.humans[cured_index].present_state != State::Infected {
+                    {
-                println!("not infected");
+                        let humans = humans.read().unwrap();
+                        debug_assert_eq!(humans[cured_index].present_state, State::Infected, "This human should be infected: {:?}", humans[cured_index].present_state);
+                    }
+                    {
+                        // eprint!("c");
+                        let mut humans = humans.write().unwrap();
+                        humans[cured_index].present_state = State::Immune;
                     }
-            self.humans[cured_index].present_state = State::Immune;
                     //DEBUG
                     //println!("Cured someone");
                 }
+            }));
+        }
 
+        {
+            let humans = Arc::clone(&self.humans);
+            let width = self.width;
+            threads.push(thread::spawn(move || {
                 for dead_position in people_to_kill.iter() {
                     //people_to_kill.iter().map(|dead_position|{
-            let dead_index = human_idx(dead_position.x, dead_position.y, self.width);
+                    let dead_index = human_idx(dead_position.x, dead_position.y, width);
-            if self.humans[dead_index].present_state == State::Dead {
+                    {
-                // println!("Already dead");
+                        let humans = humans.read().unwrap();
-            } else {
+                        debug_assert!(humans[dead_index].present_state != State::Dead);
-                self.humans[dead_index].present_state = State::Dead;
                     }
-            //DEBUG
+                    {
+                        // eprint!("k");
+                        let mut humans = humans.write().unwrap();
+                        humans[dead_index].present_state = State::Dead;
                     }
-        assert_eq!(
+                }
-            stats[0] + stats[1] + stats[2] + stats[3],
+            }));
-            self.size as i32
+        }
-        );
+
+        for t in threads {
+            t.join().unwrap();
+        }
+
+        #[cfg(debug_assertions)]
+        println!("after kills and co {:?}", timer.elapsed());
+
         stats
     }
 
@@ -270,450 +421,24 @@ pub fn roll(probability: i32) -> bool {
     }
 }
 
-#[cfg(test)]
+fn fn_is_inside(pos: &Point, width: i32, height: i32) -> bool {
-mod tests {
+    if (pos.x >= 0) && (pos.x < width) && (pos.y >= 0) && (pos.y < height) {
-    use super::*;
+        true
-    use parameterized::parameterized;
+    } else {
-
+        false
-    #[derive(Debug)]
-    struct Stats {
-        normal: i32,
-        infected: i32,
-        immune: i32,
-        dead: i32,
-    }
-
-    impl Stats {
-        fn new() -> Stats {
-            Stats {
-                normal: 0,
-                infected: 0,
-                immune: 0,
-                dead: 0,
-            }
-        }
-    }
-
-    fn humans_stats(humans: &Vec<Human>) -> Stats {
-        let mut stats: Stats = Stats::new();
-        for human in humans.iter() {
-            match human.present_state {
-                State::Normal => {
-                    stats.normal += 1;
-                }
-                State::Infected => {
-                    stats.infected += 1;
-                }
-                State::Immune => {
-                    stats.immune += 1;
-                }
-                State::Dead => {
-                    stats.dead += 1;
-                }
-            }
-        }
-        stats
-    }
-
-    #[parameterized(x = {
-        2, 3, 5
-    }, y = {
-        1, 4, 0
-    }, width = {
-        3, 5, 7
-    }, res = {
-        5, 23, 5
-    })]
-    fn test_human_idx(x: i32, y: i32, width: i32, res: usize) {
-        assert_eq!(human_idx(x, y, width), res);
-    }
-
-    #[test]
-    fn test_human_stats() {
-        let mut humans: Vec<Human> = Vec::with_capacity(10);
-        let mut stats: Stats;
-
-        for _ in 0..10 {
-            humans.push(Human {
-                present_state: State::Normal,
-                x: 0,
-                y: 0,
-            });
-        }
-        stats = humans_stats(&humans);
-        assert_eq!(stats.normal, 10);
-
-        for x in 0..2 {
-            humans[x].present_state = State::Infected;
-        }
-        for x in 2..5 {
-            humans[x].present_state = State::Immune;
-        }
-        for x in 5..9 {
-            humans[x].present_state = State::Dead;
-        }
-        stats = humans_stats(&humans);
-        assert_eq!(stats.normal, 1);
-        assert_eq!(stats.infected, 2);
-        assert_eq!(stats.immune, 3);
-        assert_eq!(stats.dead, 4);
-    }
-
-    #[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 h in population.humans.iter() {
-            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 population = Population::new(20, 10, 5, 5, 7, disease);
-
-        let stats: Stats = humans_stats(&population.humans);
-        println!("Stats: {:?}", stats);
-
-        assert_eq!(
-            stats.normal + stats.infected + stats.immune + stats.dead,
-            width * height
-        );
-    }
-
-    #[test]
-    fn plague_init_stats() {
-        let mut disease: Disease;
-        let mut population: Population;
-        let mut stats: Stats;
-        let (width, height) = (5, 7);
-
-        disease = Disease::new(0, 0, 0, String::from("Test"));
-        population = Population::new(0, 0, 0, width, height, disease);
-        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);
-        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);
-        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);
-        stats = humans_stats(&population.humans);
-        println!("should be dead: {:?}", stats);
-        assert_eq!(stats.dead, width * height);
-    }
-
-    #[parameterized(rate = {0, 100}, expected = {false, true})]
-    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();
-        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();
-            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();
-        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();
-            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();
-        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();
-        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();
-            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();
-
-        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);
-
-        stats = humans_stats(&population.humans);
-        println!("Population after init: {:?}", stats);
-
-        // 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();
-
-        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);
-        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);
     }
 }
+
+fn fn_is_inside_and_infected(point: Point, width: i32, height: i32, humans: &Vec<Human>, infection_rate: i32) -> bool {
+    if fn_is_inside(&point, width, height) {
+        let idx = human_idx(point.x, point.y, width);
+        if humans[idx].present_state == State::Infected {
+            roll(infection_rate)
+        } else {
+            false
+        }
+    } else {
+        false
+    }
+}
+

src/tests.rs

@@ -0,0 +1,448 @@
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use parameterized::parameterized;
+
+    #[derive(Debug)]
+    struct Stats {
+        normal: i32,
+        infected: i32,
+        immune: i32,
+        dead: i32,
+    }
+
+    impl Stats {
+        fn new() -> Stats {
+            Stats {
+                normal: 0,
+                infected: 0,
+                immune: 0,
+                dead: 0,
+            }
+        }
+    }
+
+    fn humans_stats(humans: &Vec<Human>) -> Stats {
+        let mut stats: Stats = Stats::new();
+        for human in humans.iter() {
+            match human.present_state {
+                State::Normal => {
+                    stats.normal += 1;
+                }
+                State::Infected => {
+                    stats.infected += 1;
+                }
+                State::Immune => {
+                    stats.immune += 1;
+                }
+                State::Dead => {
+                    stats.dead += 1;
+                }
+            }
+        }
+        stats
+    }
+
+    #[parameterized(x = {
+        2, 3, 5
+    }, y = {
+        1, 4, 0
+    }, width = {
+        3, 5, 7
+    }, res = {
+        5, 23, 5
+    })]
+    fn test_human_idx(x: i32, y: i32, width: i32, res: usize) {
+        assert_eq!(human_idx(x, y, width), res);
+    }
+
+    #[test]
+    fn test_human_stats() {
+        let mut humans: Vec<Human> = Vec::with_capacity(10);
+        let mut stats: Stats;
+
+        for _ in 0..10 {
+            humans.push(Human {
+                present_state: State::Normal,
+                x: 0,
+                y: 0,
+            });
+        }
+        stats = humans_stats(&humans);
+        assert_eq!(stats.normal, 10);
+
+        for x in 0..2 {
+            humans[x].present_state = State::Infected;
+        }
+        for x in 2..5 {
+            humans[x].present_state = State::Immune;
+        }
+        for x in 5..9 {
+            humans[x].present_state = State::Dead;
+        }
+        stats = humans_stats(&humans);
+        assert_eq!(stats.normal, 1);
+        assert_eq!(stats.infected, 2);
+        assert_eq!(stats.immune, 3);
+        assert_eq!(stats.dead, 4);
+    }
+
+    #[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);
+        let humans = Arc::clone(&population.humans);
+        assert_eq!(humans.lock().unwrap().len(), 5 * 7);
+        for h in humans.lock().unwrap().iter() {
+            let idx = human_idx(h.x, h.y, width);
+            assert_eq!(humans.lock().unwrap()[idx].x, h.x, "coordinates should match");
+            assert_eq!(humans.lock().unwrap()[idx].y, h.y, "coordinates should match");
+        }
+        assert_eq!(humans.lock().unwrap().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 population = Population::new(20, 10, 5, 5, 7, disease);
+
+        let stats: Stats = humans_stats(&population.humans);
+        println!("Stats: {:?}", stats);
+
+        assert_eq!(
+            stats.normal + stats.infected + stats.immune + stats.dead,
+            width * height
+        );
+    }
+
+    #[test]
+    fn plague_init_stats() {
+        let mut disease: Disease;
+        let mut population: Population;
+        let mut stats: Stats;
+        let (width, height) = (5, 7);
+
+        disease = Disease::new(0, 0, 0, String::from("Test"));
+        population = Population::new(0, 0, 0, width, height, disease);
+        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);
+        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);
+        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);
+        stats = humans_stats(&population.humans);
+        println!("should be dead: {:?}", stats);
+        assert_eq!(stats.dead, width * height);
+    }
+
+    #[parameterized(rate = {0, 100}, expected = {false, true})]
+    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();
+        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();
+            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();
+        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();
+            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();
+        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();
+        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();
+            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();
+
+        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);
+
+        stats = humans_stats(&population.humans);
+        println!("Population after init: {:?}", stats);
+
+        // 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();
+
+        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);
+        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);
+    }
+}