diff --git a/csg/src/plane.rs b/csg/src/plane.rs
index ebaf997..0afc3f5 100644
--- a/csg/src/plane.rs
+++ b/csg/src/plane.rs
@@ -106,3 +106,90 @@ impl PlaneIntersection {
         .transpose()
     }
 }
+
+#[cfg(test)]
+mod plane_tests {
+    use super::*;
+
+    #[test]
+    fn from_point_normal() {
+        let point = glam::vec3(1.0, 1.0, 0.0);
+        let normal = glam::vec3(1.0, 1.0, 1.0);
+
+        let expected = Plane {
+            normal,
+            offset: 2.0,
+        };
+
+        assert_eq!(Plane::from_point_normal(point, normal), expected);
+    }
+}
+
+#[cfg(test)]
+mod plane_intersection_tests {
+    use super::*;
+
+    #[test]
+    fn from_planes() {
+        let planes = vec![
+            Plane::from_point_normal(Vec3::X, Vec3::X),
+            Plane::from_point_normal(Vec3::Y, Vec3::Y),
+            Plane::from_point_normal(Vec3::Z, Vec3::Z),
+            Plane::from_point_normal(Vec3::NEG_X, Vec3::NEG_X),
+        ];
+
+        let intersection1 = PlaneIntersection::from_planes(planes[0], planes[1], planes[2]);
+        let intersection2 = PlaneIntersection::from_planes(planes[0], planes[1], planes[3]);
+
+        assert!(intersection1.is_some());
+        assert!(intersection2.is_none());
+    }
+
+    #[test]
+    fn get_intersection_point() {
+        let planes = vec![
+            Plane::from_point_normal(Vec3::X, Vec3::X),
+            Plane::from_point_normal(Vec3::Y, Vec3::Y),
+            Plane::from_point_normal(Vec3::Z, Vec3::Z),
+            Plane::from_point_normal(glam::vec3(1.0, 1.0, 0.0), Vec3::ONE),
+        ];
+
+        let intersection1 = PlaneIntersection::from_planes(planes[0], planes[1], planes[2]);
+        let intersection2 = PlaneIntersection::from_planes(planes[0], planes[1], planes[3]);
+        assert_eq!(intersection1.unwrap().get_intersection_point(), Vec3::ONE);
+        assert_eq!(
+            intersection2.unwrap().get_intersection_point(),
+            glam::vec3(1.0, 1.0, 0.0)
+        );
+    }
+
+    #[test]
+    fn in_half_space_mat() {
+        let intersection = PlaneIntersection::from_planes(
+            Plane::from_point_normal(Vec3::X, Vec3::X),
+            Plane::from_point_normal(Vec3::Y, Vec3::Y),
+            Plane::from_point_normal(Vec3::Z, Vec3::Z),
+        )
+        .unwrap();
+
+        let p1 = Plane::from_point_normal(Vec3::NEG_ONE, Vec3::NEG_ONE);
+        let p2 = Plane::from_point_normal(Vec3::ZERO, Vec3::ONE);
+        assert!(intersection.in_halfspace_mat(&p1));
+        assert!(!intersection.in_halfspace_mat(&p2));
+    }
+
+    #[test]
+    fn in_half_space() {
+        let intersection = PlaneIntersection::from_planes(
+            Plane::from_point_normal(Vec3::X, Vec3::X),
+            Plane::from_point_normal(Vec3::Y, Vec3::Y),
+            Plane::from_point_normal(Vec3::Z, Vec3::Z),
+        )
+        .unwrap();
+
+        let p1 = Plane::from_point_normal(Vec3::NEG_ONE, Vec3::NEG_ONE);
+        let p2 = Plane::from_point_normal(Vec3::ZERO, Vec3::ONE);
+        assert!(intersection.in_halfspace(&p1));
+        assert!(!intersection.in_halfspace(&p2));
+    }
+}