diff --git a/tests/test_flatland_core_grid_grid_utils.py b/tests/test_flatland_core_grid_grid_utils.py
index 35ecd247dc9908c4c70529ad977e22b45f8add1d..d598255375b6b86cb44132e03796403b968676c0 100644
--- a/tests/test_flatland_core_grid_grid_utils.py
+++ b/tests/test_flatland_core_grid_grid_utils.py
@@ -2,8 +2,6 @@ import numpy as np
 
 from flatland.core.grid.grid_utils import Vec2dOperations as Vec2d
 
-machine_epsilon = 10.0 * np.finfo(float).eps
-
 
 def test_vec2d_is_equal():
     node_a = (1, 2)
@@ -79,8 +77,8 @@ def test_vec2d_normalize():
     node_b = (1, -2)
     res_1 = Vec2d.normalize(node_a)
     res_2 = Vec2d.normalize(node_b)
-    assert (1.0 - Vec2d.get_norm(res_1)) < machine_epsilon
-    assert (1.0 - Vec2d.get_norm(res_2)) < machine_epsilon
+    assert np.isclose(1.0, Vec2d.get_norm(res_1))
+    assert np.isclose(1.0, Vec2d.get_norm(res_2))
 
 
 def test_vec2d_scale():
@@ -144,9 +142,9 @@ def test_vec2d_rotate():
     res_5 = (Vec2d.get_norm(Vec2d.subtract(res_5, (-2.2, 1.95))))
     res_6 = (Vec2d.get_norm(Vec2d.subtract(res_6, (-0.5887495373796556, -2.880255888325765))))
 
-    assert res_1 < machine_epsilon
-    assert res_2 < machine_epsilon
-    assert res_3 < machine_epsilon
-    assert res_4 < machine_epsilon
-    assert res_5 < machine_epsilon
-    assert res_6 < machine_epsilon
+    assert np.isclose(0, res_1)
+    assert np.isclose(0, res_2)
+    assert np.isclose(0, res_3)
+    assert np.isclose(0, res_4)
+    assert np.isclose(0, res_5)
+    assert np.isclose(0, res_6)
diff --git a/tests/test_flatland_envs_city_generator.py b/tests/test_flatland_envs_city_generator.py
index a7a96e51d5d6afa62f9edbec0fa69ab05ebae12a..353bb1d414e5fe2ca57831ada73cdaa1851be391 100644
--- a/tests/test_flatland_envs_city_generator.py
+++ b/tests/test_flatland_envs_city_generator.py
@@ -26,6 +26,7 @@ def test_city_generator():
                   number_of_agents=10,
                   obs_builder_object=GlobalObsForRailEnv())
 
+    # approximative test (replace image comparison)
     assert (np.sum(env.rail.grid) == 2718122)
     s0 = 0
     s1 = 0
diff --git a/tests/test_flatland_envs_sparse_rail_generator.py b/tests/test_flatland_envs_sparse_rail_generator.py
index 19c2614edac28a413d86a722dd5292a7a1b2c642..c32b3c3e3309069a3232393a45997434af3cfb96 100644
--- a/tests/test_flatland_envs_sparse_rail_generator.py
+++ b/tests/test_flatland_envs_sparse_rail_generator.py
@@ -24,6 +24,7 @@ def test_sparse_rail_generator():
                   number_of_agents=10,
                   obs_builder_object=GlobalObsForRailEnv())
 
+    # approximative test (replace image comparison)
     assert (np.sum(env.rail.grid) == 10746925)
     s0 = 0
     s1 = 0