diff --git a/cura/BuildVolume.py b/cura/BuildVolume.py
index 37a2a9895e..0bfbe2b1d5 100755
--- a/cura/BuildVolume.py
+++ b/cura/BuildVolume.py
@@ -28,10 +28,11 @@ import numpy
 import math
 import copy
 
-from typing import List, Optional, TYPE_CHECKING, Any, Set, cast, Iterable
+from typing import List, Optional, TYPE_CHECKING, Any, Set, cast, Iterable, Dict
 
 if TYPE_CHECKING:
     from cura.CuraApplication import CuraApplication
+    from cura.Settings.ExtruderStack import ExtruderStack
 
 # Radius of disallowed area in mm around prime. I.e. how much distance to keep from prime position.
 PRIME_CLEARANCE = 6.5
@@ -868,9 +869,10 @@ class BuildVolume(SceneNode):
     #   \param used_extruders The extruder stacks to generate disallowed areas
     #   for.
     #   \return A dictionary with for each used extruder ID the prime areas.
-    def _computeDisallowedAreasPrimeBlob(self, border_size, used_extruders):
-        result = {}
-
+    def _computeDisallowedAreasPrimeBlob(self, border_size: float, used_extruders: List["ExtruderStack"]) -> Dict[str, List[Polygon]]:
+        result = {}  # type: Dict[str, List[Polygon]]
+        if not self._global_container_stack:
+            return result
         machine_width = self._global_container_stack.getProperty("machine_width", "value")
         machine_depth = self._global_container_stack.getProperty("machine_depth", "value")
         for extruder in used_extruders:
@@ -878,13 +880,13 @@ class BuildVolume(SceneNode):
             prime_x = extruder.getProperty("extruder_prime_pos_x", "value")
             prime_y = -extruder.getProperty("extruder_prime_pos_y", "value")
 
-            #Ignore extruder prime position if it is not set or if blob is disabled
+            # Ignore extruder prime position if it is not set or if blob is disabled
             if (prime_x == 0 and prime_y == 0) or not prime_blob_enabled:
                 result[extruder.getId()] = []
                 continue
 
             if not self._global_container_stack.getProperty("machine_center_is_zero", "value"):
-                prime_x = prime_x - machine_width / 2 #Offset by half machine_width and _depth to put the origin in the front-left.
+                prime_x = prime_x - machine_width / 2  # Offset by half machine_width and _depth to put the origin in the front-left.
                 prime_y = prime_y + machine_depth / 2
 
             prime_polygon = Polygon.approximatedCircle(PRIME_CLEARANCE)
diff --git a/tests/TestBuildVolume.py b/tests/TestBuildVolume.py
index facdbfe143..640673e773 100644
--- a/tests/TestBuildVolume.py
+++ b/tests/TestBuildVolume.py
@@ -2,11 +2,16 @@ from unittest.mock import MagicMock, patch
 
 import pytest
 
-from cura.BuildVolume import BuildVolume
+from UM.Math.Polygon import Polygon
+from UM.Settings.SettingInstance import InstanceState
+from cura.BuildVolume import BuildVolume, PRIME_CLEARANCE
 import numpy
 
+
+
+
 @pytest.fixture
-def build_volume():
+def build_volume() -> BuildVolume:
     mocked_application = MagicMock()
     mocked_platform = MagicMock(name="platform")
     with patch("cura.BuildVolume.Platform", mocked_platform):
@@ -36,3 +41,48 @@ def test_buildGridMesh(build_volume):
     mesh = build_volume._buildGridMesh(0, 100, 0, 100, 0, 100, 1)
     result_vertices = numpy.array([[0., -1., 0.], [100., -1., 100.], [100., -1., 0.], [0., -1., 0.], [0., -1., 100.], [100., -1., 100.]])
     assert numpy.array_equal(result_vertices, mesh.getVertices())
+
+
+class TestComputeDisallowedAreasPrimeBlob:
+    setting_property_dict = {"machine_width": {"value": 50},
+                             "machine_depth": {"value": 100},
+                             "prime_blob_enable": {"value": True},
+                             "extruder_prime_pos_x":  {"value": 25},
+                             "extruder_prime_pos_y": {"value": 50},
+                             "machine_center_is_zero": {"value": True},
+                             }
+
+    def getPropertySideEffect(*args, **kwargs):
+        properties = TestComputeDisallowedAreasPrimeBlob.setting_property_dict.get(args[1])
+        if properties:
+            return properties.get(args[2])
+
+    def test_noGlobalContainer(self, build_volume: BuildVolume):
+        # No global container and no extruders, so we expect no blob areas
+        assert build_volume._computeDisallowedAreasPrimeBlob(12, []) == {}
+
+    def test_noExtruders(self, build_volume: BuildVolume):
+        mocked_stack = MagicMock()
+        mocked_stack.getProperty = MagicMock(side_effect=self.getPropertySideEffect)
+
+        build_volume._global_container_stack = mocked_stack
+        # No extruders, so still expect that we get no area
+        assert build_volume._computeDisallowedAreasPrimeBlob(12, []) == {}
+
+    def test_singleExtruder(self, build_volume: BuildVolume):
+        mocked_global_stack = MagicMock(name = "mocked_global_stack")
+        mocked_global_stack.getProperty = MagicMock(side_effect=self.getPropertySideEffect)
+
+        mocked_extruder_stack = MagicMock(name = "mocked_extruder_stack")
+        mocked_extruder_stack.getId = MagicMock(return_value = "0")
+        mocked_extruder_stack.getProperty = MagicMock(side_effect=self.getPropertySideEffect)
+
+        build_volume._global_container_stack = mocked_global_stack
+
+        # Create a polygon that should be the result
+        resulting_polygon = Polygon.approximatedCircle(PRIME_CLEARANCE)
+        # Since we want a blob of size 12;
+        resulting_polygon = resulting_polygon.getMinkowskiHull(Polygon.approximatedCircle(12))
+        # In the The translation result is 25, -50 (due to the settings used)
+        resulting_polygon = resulting_polygon.translate(25, -50)
+        assert build_volume._computeDisallowedAreasPrimeBlob(12, [mocked_extruder_stack]) == {"0": [resulting_polygon]}