diff --git a/.idea/MatrixMania.iml b/.idea/MatrixMania.iml
index 51bcf32..3b1d427 100644
--- a/.idea/MatrixMania.iml
+++ b/.idea/MatrixMania.iml
@@ -7,4 +7,10 @@
     <orderEntry type="jdk" jdkName="Python 3.12 (MatrixMania)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
+  <component name="PackageRequirementsSettings">
+    <option name="requirementsPath" value="" />
+  </component>
+  <component name="TestRunnerService">
+    <option name="PROJECT_TEST_RUNNER" value="py.test" />
+  </component>
 </module>
\ No newline at end of file
diff --git a/matrixmania/compute.py b/matrixmania/compute.py
index e9b3c0a..3e1c779 100644
--- a/matrixmania/compute.py
+++ b/matrixmania/compute.py
@@ -74,7 +74,32 @@ def rot_2D(angle: int) -> List[List[float]]:
 
     return [[zahl1, zahl2], [zahl3, zahl4]]
 
+def rot_3D(angle: float, axis: str) -> List[List[float]]:
+    """
+    Rotation matrix 3D
+    :param angle: between 0 and 360 degrees
+    :param axis: x,y,z axis of rotation matrix
+    :return: 3D rotation matrix
+    """
+    if angle > 360:
+        raise ValueError("angle must be less than 360")
+    elif angle < 0:
+        raise ValueError("angle must be greater than 0")
+
+    cos = math.cos(math.radians(angle))
+    sin = math.sin(math.radians(angle))
+
+    if axis == "x":
+        return [[1,0,0],[0, cos, -sin],[0, sin, cos]]
+    elif axis == "y":
+        return [[cos, 0, sin],[0,1,0],[-sin,0,cos]]
+    elif axis == "z":
+        return [[cos, -sin, 0],[sin, cos, 0],[0, 0, 1]]
+
+    else:
+        raise ValueError("Not a valid axis. Choose from 'x', 'y', 'z'.")
+
 
 if __name__ == "__main__":
-    "alles selbst gemacht"
-    print(rot_2D())
\ No newline at end of file
+
+    print(rot_3D(90, "x"))
\ No newline at end of file
diff --git a/tests/test_matmul.py b/tests/test_matmul.py
index a56903d..240618e 100644
--- a/tests/test_matmul.py
+++ b/tests/test_matmul.py
@@ -12,4 +12,5 @@ def test_matmul():
     matrix_c = matmul(matrix_a, matrix_b)
     print(f"Matrix A: {matrix_a} mal Matrix B: {matrix_b} = Matrix C: {matrix_c}")
 
+    assert matrix_c == [[20, 37, 26], [-1, 27, -8]]
 
diff --git a/tests/test_rot.py b/tests/test_rot2D.py
similarity index 63%
rename from tests/test_rot.py
rename to tests/test_rot2D.py
index 5c9b55d..3b92cca 100644
--- a/tests/test_rot.py
+++ b/tests/test_rot2D.py
@@ -5,4 +5,6 @@ def test_rot_2D():
     result = rot_2D(angle)
     print(f"Angle:{angle}   Rot-Matrix:{result}")
 
+    assert result == [[6.123233995736766e-17, -1.0], [1.0, 6.123233995736766e-17]]
+
 
diff --git a/tests/test_rot3D.py b/tests/test_rot3D.py
new file mode 100644
index 0000000..ad408f3
--- /dev/null
+++ b/tests/test_rot3D.py
@@ -0,0 +1 @@
+from matrixmania import rot_3D
\ No newline at end of file
diff --git a/tests/test_transpose.py b/tests/test_transpose.py
new file mode 100644
index 0000000..b73f7bd
--- /dev/null
+++ b/tests/test_transpose.py
@@ -0,0 +1 @@
+from matrixmania import transpose