test: add tests and trait impls in earthlike.rs

* add a test for the `Material2d`'s `fragement_shader()` fn impl for `Earthlike`
* add `randomise()`, `randomise_seed()`, `randomise_rotation()`, and `set_*()` functions as impls for `PlanetShader` trait

src/game.rs

@@ -53,7 +53,7 @@ fn setup(
                     pixels: 100.,
                     rotation: 90f32.to_radians(),
                     radius: 100.,
-                    time_speed: 0.2,
+                    time_speed: 10.,
                 },
                 land_colours: [
                     Color::rgb(0.388235, 0.670588, 0.247059),

src/shaders.rs

@@ -79,7 +79,26 @@ impl Default for CelestialSettings {
     }
 }
 
-pub trait PlanetShader: ShaderType + Component + AsBindGroup + Material2d {}
+pub trait PlanetShader: ShaderType + Component + AsBindGroup + Material2d {
+    fn randomise(&mut self) {
+        self.randomise_seed();
+        self.randomise_rotation();
+    }
+    fn randomise_seed(&mut self) {
+        self.set_seed(rand::thread_rng().gen());
+    }
+    fn randomise_rotation(&mut self) {
+        self.set_rotation(rand::thread_rng().gen_range(0f32..TAU));
+    }
+
+    fn set_seed(&mut self, seed: f32) {}
+
+    fn set_rotation(&mut self, rotation: f32) {}
+
+    fn set_pixels(&mut self, pixels: f32) {}
+
+    fn set_time_speed(&mut self, time_speed: f32) {}
+}
 
 #[derive(Bundle, Reflect, Default, Clone)]
 pub struct CelestialBundle<P: PlanetShader> {

src/shaders/cloud_cover.rs

@@ -30,7 +30,7 @@ impl Default for CloudCover {
 
 impl Material2d for CloudCover {
     fn fragment_shader() -> ShaderRef {
-        "shaderS/celestials/generic/cloud_cover.wgsl".into()
+        "shaders/celestials/generic/cloud_cover.wgsl".into()
     }
 }
 

src/shaders/earthlike.rs

@@ -19,17 +19,12 @@ pub struct Earthlike {
     pub river_colours: [Color; 2],
 }
 
-impl Earthlike {
-    pub(crate) fn randomise(&mut self) {
-        self.randomise_rotation();
-        self.randomise_seed();
-    }
-
-    pub(crate) fn randomise_seed(&mut self) {
+impl PlanetShader for Earthlike {
+    fn randomise_seed(&mut self) {
         self.celestial.seed = rand::thread_rng().gen();
     }
 
-    pub(crate) fn randomise_rotation(&mut self) {
+    fn randomise_rotation(&mut self) {
         self.celestial.rotation = rand::thread_rng().gen_range(0f32..TAU);
     }
 }
@@ -58,13 +53,29 @@ impl Material2d for Earthlike {
     }
 }
 
-impl PlanetShader for Earthlike {}
-
 #[cfg(test)]
 mod test {
 
+    use bevy::{asset::AssetPath, render::render_resource::ShaderRef, sprite::Material2d};
+
     use crate::prelude::*;
 
+    #[test]
+    fn test_earthlike_material2d_impl() {
+        let shader_ref = Earthlike::fragment_shader();
+
+        let ShaderRef::Path(asset_path) = shader_ref else {
+
+            panic!("\"ShaderRef\" from \"Earthlike::fragment_shader()\" isn't of enum variant \"ShaderRef::Path\"");
+
+        };
+
+        assert_eq!(
+            asset_path,
+            AssetPath::from("shaders/celestials/earthlike.wgsl")
+        );
+    }
+
     #[test]
     fn test_earthlike_randomise() {
         let first = Earthlike::default();