diff --git a/tardis/montecarlo/montecarlo_numba/tests/test_packet.py b/tardis/montecarlo/montecarlo_numba/tests/test_packet.py
index 752378cb51b..891a213928d 100644
--- a/tardis/montecarlo/montecarlo_numba/tests/test_packet.py
+++ b/tardis/montecarlo/montecarlo_numba/tests/test_packet.py
@@ -154,52 +154,6 @@ def test_calculate_tau_electron(electron_density, distance):
     assert_almost_equal(actual, expected)
 
 
-@pytest.mark.parametrize(
-    ["mu", "r", "inv_t_exp", "expected"],
-    [
-        (0.3, 7.5e14, 1 / 5.2e7, 0.9998556693818854),
-        (-0.3, 0, 1 / 2.6e7, 1.0),
-        (0, 1, 1 / 2.6e7, 1.0),
-    ],
-)
-def test_get_doppler_factor(mu, r, inv_t_exp, expected):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-
-    obtained = frame_transformations.get_doppler_factor(r, mu, time_explosion)
-
-    # Perform required assertions
-    assert_almost_equal(obtained, expected)
-
-
-@pytest.mark.parametrize(
-    ["mu", "r", "inv_t_exp", "expected"],
-    [
-        (0.3, 7.5e14, 1 / 5.2e7, 1 / 0.9998556693818854),
-        (-0.3, 0, 1 / 2.6e7, 1.0),
-        (0, 1, 1 / 2.6e7, 1.0),
-    ],
-)
-def test_get_inverse_doppler_factor(mu, r, inv_t_exp, expected):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-
-    obtained = frame_transformations.get_inverse_doppler_factor(
-        r, mu, time_explosion
-    )
-
-    # Perform required assertions
-    assert_almost_equal(obtained, expected)
-
-
 def test_get_random_mu(set_seed_fixture):
     """
     Ensure that different calls results
diff --git a/tardis/montecarlo/tests/test_montecarlo.py b/tardis/montecarlo/tests/test_montecarlo.py
index 80d131a8e4c..363d54be899 100644
--- a/tardis/montecarlo/tests/test_montecarlo.py
+++ b/tardis/montecarlo/tests/test_montecarlo.py
@@ -238,120 +238,6 @@ def test_binary_search(x, x_insert, imin, imax, expected_params):
     assert obtained_result == expected_params["result"]
 
 
-@pytest.mark.parametrize(
-    ["mu", "r", "inv_t_exp", "expected"],
-    [
-        (0.3, 7.5e14, 1 / 5.2e7, 0.9998556693818854),
-        (-0.3, 0, 1 / 2.6e7, 1.0),
-        (0, 1, 1 / 2.6e7, 1.0),
-    ],
-)
-def test_get_doppler_factor(mu, r, inv_t_exp, expected):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-
-    obtained = get_doppler_factor(r, mu, time_explosion)
-
-    # Perform required assertions
-    assert_almost_equal(obtained, expected)
-
-
-@pytest.mark.parametrize(["mu", "r", "inv_t_exp"], [(-0.3, 5, 1e10)])
-def test_unphysical_doppler_factor(mu, r, inv_t_exp):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-    with pytest.raises(r_packet.SuperluminalError):
-        obtained = get_doppler_factor(r, mu, time_explosion)
-
-
-@pytest.mark.parametrize(
-    ["mu", "r", "inv_t_exp", "expected"],
-    [
-        (0.3, 7.5e14, 1 / 5.2e7, 1 / 0.9998556693818854),
-        (-0.3, 0, 1 / 2.6e7, 1.0),
-        (0, 1, 1 / 2.6e7, 1.0),
-    ],
-)
-def test_get_inverse_doppler_factor(mu, r, inv_t_exp, expected):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-
-    obtained = r_packet.get_inverse_doppler_factor(r, mu, time_explosion)
-
-    # Perform required assertions
-    assert_almost_equal(obtained, expected)
-
-
-@pytest.mark.parametrize(["mu", "r", "inv_t_exp"], [(-0.3, 5, 1e10)])
-def test_unphysical_inverse_doppler_factor(mu, r, inv_t_exp):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-    with pytest.raises(r_packet.SuperluminalError):
-        obtained = r_packet.get_inverse_doppler_factor(r, mu, time_explosion)
-
-
-@pytest.mark.parametrize(
-    ["mu", "r", "inv_t_exp", "expected"],
-    [
-        (-0.3, 10000000, 0.001, 1.0000001000692842),
-        (-0.3, 0, 1 / 2.6e7, 1.0),
-        (0, 1, 1 / 2.6e7, 1.0),
-    ],
-)
-def test_get_doppler_factor_full_relativity(mu, r, inv_t_exp, expected):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    mc.full_relativity = True
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-
-    obtained = get_doppler_factor(r, mu, time_explosion)
-    mc.full_relativity = False
-    # Perform required assertions
-    assert_almost_equal(obtained, expected)
-
-
-@pytest.mark.parametrize(
-    ["mu", "r", "inv_t_exp", "expected"],
-    [
-        (-0.3, 10000000, 0.001, 0.999999899930827),
-        (-0.3, 0, 1 / 2.6e7, 1.0),
-        (0, 1, 1 / 2.6e7, 1.0),
-    ],
-)
-def test_get_inverse_doppler_factor_full_relativity(mu, r, inv_t_exp, expected):
-    # Set the params from test cases here
-    # TODO: add relativity tests
-    mc.full_relativity = True
-    time_explosion = 1 / inv_t_exp
-
-    # Perform any other setups just before this, they can be additional calls
-    # to other methods or introduction of some temporary variables
-
-    obtained = r_packet.get_inverse_doppler_factor(r, mu, time_explosion)
-    mc.full_relativity = False
-    # Perform required assertions
-    assert_almost_equal(obtained, expected)
-
-
 def test_get_random_mu_different_output():
     """
     Ensure that different calls results
diff --git a/tardis/transport/tests/test_doppler_factor.py b/tardis/transport/tests/test_doppler_factor.py
new file mode 100644
index 00000000000..4d1ff158970
--- /dev/null
+++ b/tardis/transport/tests/test_doppler_factor.py
@@ -0,0 +1,191 @@
+import pytest
+import numpy as np
+
+import tardis.transport.frame_transformations as frame_transformations
+import tardis.montecarlo.montecarlo_numba.r_packet as r_packet
+
+from numpy.testing import (
+    assert_almost_equal,
+)
+
+
+@pytest.mark.parametrize(
+    ["mu", "r", "inv_t_exp", "expected"],
+    [
+        (0.3, 7.5e14, 1 / 5.2e7, 0.9998556693818854),
+        (-0.3, 0, 1 / 2.6e7, 1.0),
+        (0, 1, 1 / 2.6e7, 1.0),
+    ],
+)
+def test_get_doppler_factor(mu, r, inv_t_exp, expected):
+    """
+    Checks the get_doppler_factor function.
+
+    Parameters
+    ----------
+    mu : float
+        Angle of movement of the packet.
+    r : float
+        Radius of the position of the packet.
+    inv_t_exp : float
+        Inverse of t_explosion.
+    expected : float
+        Expected value of the doppler factor.
+    """
+    # Set the params from test cases here
+    time_explosion = 1 / inv_t_exp
+
+    # Perform any other setups just before this, they can be additional calls
+    # to other methods or introduction of some temporary variables
+
+    obtained = frame_transformations.get_doppler_factor(r, mu, time_explosion)
+
+    # Perform required assertions
+    assert_almost_equal(obtained, expected)
+
+
+@pytest.mark.parametrize(
+    ["mu", "beta", "expected"],
+    [
+        (0.3, 0.2, 0.94),
+        (-0.3, 0, 1.0),
+        (0, 0.8, 1.0),
+    ],
+)
+def test_get_doppler_factor_partial_relativity(mu, beta, expected):
+    """
+    Checks the get_doppler_factor_partial_relativity.
+
+    Parameters
+    ----------
+    mu : float
+        Angle of movement of the packet.
+    beta : float
+        Velocity over speed of light for the packet.
+    expected : float
+        Expected value of the doppler factor.
+    """
+    obtained = frame_transformations.get_doppler_factor_partial_relativity(
+        mu, beta
+    )
+    assert_almost_equal(obtained, expected)
+
+
+@pytest.mark.parametrize(
+    ["mu", "beta", "expected"],
+    [
+        (0.3, 0.2, 0.95938348),
+        (-0.3, 0, 1.0),
+        (0, 0.8, 1.6666667),
+    ],
+)
+def test_get_doppler_factor_full_relativity(mu, beta, expected):
+    """
+    Checks the get_doppler_factor_full_relativity.
+
+    Parameters
+    ----------
+    mu : float
+        Angle of movement of the packet.
+    beta : float
+        Velocity over speed of light for the packet.
+    expected : float
+        Expected value of the doppler factor.
+    """
+    obtained = frame_transformations.get_doppler_factor_full_relativity(
+        mu, beta
+    )
+    assert_almost_equal(obtained, expected)
+
+
+@pytest.mark.parametrize(
+    ["mu", "r", "inv_t_exp", "expected"],
+    [
+        (0.3, 7.5e14, 1 / 5.2e7, 1 / 0.9998556693818854),
+        (-0.3, 0, 1 / 2.6e7, 1.0),
+        (0, 1, 1 / 2.6e7, 1.0),
+    ],
+)
+def test_get_inverse_doppler_factor(mu, r, inv_t_exp, expected):
+    """
+    Checks the get_inverse_doppler_factor function.
+
+    Parameters
+    ----------
+    mu : float
+        Angle of movement of the packet.
+    r : float
+        Radius of the position of the packet.
+    inv_t_exp : float
+        Inverse of t_explosion.
+    expected : float
+        Expected value of the inverse doppler factor.
+    """
+    # Set the params from test cases here
+    time_explosion = 1 / inv_t_exp
+
+    # Perform any other setups just before this, they can be additional calls
+    # to other methods or introduction of some temporary variables
+
+    obtained = frame_transformations.get_inverse_doppler_factor(
+        r, mu, time_explosion
+    )
+
+    # Perform required assertions
+    assert_almost_equal(obtained, expected)
+
+
+@pytest.mark.parametrize(
+    ["mu", "beta", "expected"],
+    [
+        (0.3, 0.2, 1 / 0.94),
+        (-0.3, 0, 1.0),
+        (0, 0.8, 1.0),
+    ],
+)
+def test_get_inverse_doppler_factor_partial_relativity(mu, beta, expected):
+    """
+    Checks the get_inverse_doppler_factor_partial_relativity function.
+
+    Parameters
+    ----------
+    mu : float
+        Angle of movement of the packet.
+    beta : float
+        Velocity over speed of light for the packet.
+    expected : float
+        Expected value of the inverse doppler factor.
+    """
+    obtained = (
+        frame_transformations.get_inverse_doppler_factor_partial_relativity(
+            mu, beta
+        )
+    )
+    assert_almost_equal(obtained, expected)
+
+
+@pytest.mark.parametrize(
+    ["mu", "beta", "expected"],
+    [
+        (0.3, 0.2, 1.0818579),
+        (-0.3, 0, 1.0),
+        (0, 0.8, 1.6666667),
+    ],
+)
+def test_get_inverse_doppler_factor_full_relativity(mu, beta, expected):
+    """
+    Checks the get_inverse_doppler_factor_full_relativity function.
+
+    Parameters
+    ----------
+    mu : float
+        Angle of movement of the packet.
+    beta : float
+        Velocity over speed of light for the packet.
+    expected : float
+        Expected value of the inverse doppler factor.
+    """
+    obtained = frame_transformations.get_inverse_doppler_factor_full_relativity(
+        mu, beta
+    )
+    assert_almost_equal(obtained, expected)