diff --git a/src/Quaternion/Quaternion.h b/src/Quaternion/Quaternion.h
index a1641a5..b546b61 100644
--- a/src/Quaternion/Quaternion.h
+++ b/src/Quaternion/Quaternion.h
@@ -13,10 +13,40 @@ public:
     Quaternion(const Matrix<1, 4> &matrix) : Matrix<1, 4>(matrix) {}
     Quaternion(const std::array<float, 4> &array) : Matrix<1, 4>(array) {}
 
+    /**
+     * @brief Access the elements of the quaternion
+     * @param index The index of the element to access
+     * @return The value of the element at the index
+     */
     float operator[](uint8_t index);
+
+    /**
+     * @brief Add two quaternions together
+     * @param other The quaternion to add to this one
+     * @return The net quaternion
+     */
     Quaternion operator+(const Quaternion &other);
+
+    /**
+     * @brief Rotate a quaternion by another quaternion
+     * @param other The quaternion to rotate by
+     * @param buffer The buffer to store the result in
+     * @return A reference to the buffer
+     */
     Quaternion &Rotate(Quaternion &other, Quaternion &buffer);
+
+    /**
+     * @brief Calculate the Euler angles from the quaternion
+     * @param angleBuffer The buffer to store the angles in
+     * @return A reference to the buffer
+     */
     Matrix<1, 3> &ToEulerAngles(Matrix<1, 3> &angleBuffer);
+
+    /**
+     * @brief Convert the quaternion to a rotation matrix
+     * @param rotationMatrixBuffer The buffer to store the rotation matrix in
+     * @return A reference to the buffer
+     */
     Matrix<3, 3> &ToRotationMatrix(Matrix<3, 3> &rotationMatrixBuffer);
 
     // Give people an easy way to access the elements
diff --git a/unit-tests/CMakeLists.txt b/unit-tests/CMakeLists.txt
index ab34785..9d2afc4 100644
--- a/unit-tests/CMakeLists.txt
+++ b/unit-tests/CMakeLists.txt
@@ -36,6 +36,6 @@ add_executable(quaternion-tests quaternion-tests.cpp)
  
 target_link_libraries(quaternion-tests 
     PRIVATE 
-    quaternion-intf
+    quaternion
     Catch2::Catch2WithMain
 )
\ No newline at end of file
diff --git a/unit-tests/quaternion-tests.cpp b/unit-tests/quaternion-tests.cpp
index 6737548..0b5f1ad 100644
--- a/unit-tests/quaternion-tests.cpp
+++ b/unit-tests/quaternion-tests.cpp
@@ -52,4 +52,55 @@ TEST_CASE("Vector Math", "Vector")
         REQUIRE(q6.v3 == 3);
         REQUIRE(q6.w == 4);
     }
+
+    SECTION("Array access")
+    {
+        REQUIRE(q1[0] == 1);
+        REQUIRE(q1[1] == 2);
+        REQUIRE(q1[2] == 3);
+        REQUIRE(q1[3] == 4);
+    }
+
+    SECTION("Addition")
+    {
+        Quaternion q3 = q1 + q2;
+        REQUIRE(q3.v1 == 5);
+        REQUIRE(q3.v2 == 12);
+        REQUIRE(q3.v3 == 21);
+        REQUIRE(q3.w == 32);
+    }
+
+    SECTION("Rotation")
+    {
+        Quaternion q3;
+        q1.Rotate(q2, q3);
+        REQUIRE(q3.v1 == -24);
+        REQUIRE(q3.v2 == 48);
+        REQUIRE(q3.v3 == 48);
+        REQUIRE(q3.w == -6);
+    }
+
+    SECTION("Euler Angles")
+    {
+        Matrix<1, 3> angles;
+        q1.ToEulerAngles(angles);
+        REQUIRE_THAT(angles.Get(0, 0), Catch::Matchers::WithinRel(-0.1973956f, 1e-6f));
+        REQUIRE_THAT(angles.Get(0, 1), Catch::Matchers::WithinRel(0.823212f, 1e-6f));
+        REQUIRE_THAT(angles.Get(0, 2), Catch::Matchers::WithinRel(1.3734008f, 1e-6f));
+    }
+
+    SECTION("Rotation Matrix")
+    {
+        Matrix<3, 3> rotationMatrix;
+        q1.ToRotationMatrix(rotationMatrix);
+        REQUIRE_THAT(rotationMatrix.Get(0, 0), Catch::Matchers::WithinRel(0.1333333f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(0, 1), Catch::Matchers::WithinRel(-0.6666667f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(0, 2), Catch::Matchers::WithinRel(0.7333333f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(1, 0), Catch::Matchers::WithinRel(0.9333333f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(1, 1), Catch::Matchers::WithinRel(0.3333333f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(1, 2), Catch::Matchers::WithinRel(0.1333333f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(2, 0), Catch::Matchers::WithinRel(-0.3333333f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(2, 1), Catch::Matchers::WithinRel(0.6666667f, 1e-6f));
+        REQUIRE_THAT(rotationMatrix.Get(2, 2), Catch::Matchers::WithinRel(0.6666667f, 1e-6f));
+    }
 }
\ No newline at end of file