diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 2f671da1a8..3043b2c3f6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -130,5 +130,6 @@ jobs:
           cd ../bcf && make test
           pip install requests
           cd ../bsdd && make test
+          cd ../ifcdiff && make test
           cd ../ifcpatch && make test
           cd ../ifctester && make test
diff --git a/src/ifcdiff/Makefile b/src/ifcdiff/Makefile
index 3a1b16b3e7..1aaf288b57 100644
--- a/src/ifcdiff/Makefile
+++ b/src/ifcdiff/Makefile
@@ -20,6 +20,10 @@ PACKAGE_NAME:=ifcdiff.py
 IS_MODULE:=true
 include ../common.mk
 
+.PHONY: test
+test:
+	pytest -p no:pytest-blender test.py
+
 .PHONY: qa
 qa:
 	black .
diff --git a/src/ifcdiff/test.py b/src/ifcdiff/test.py
new file mode 100644
index 0000000000..fa0aee15ea
--- /dev/null
+++ b/src/ifcdiff/test.py
@@ -0,0 +1,94 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2022 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import ifcdiff
+import ifcopenshell
+import ifcopenshell.api.context
+import ifcopenshell.api.geometry
+import ifcopenshell.api.root
+import ifcopenshell.util.representation
+
+
+def setup_project() -> ifcopenshell.file:
+    ifc_file = ifcopenshell.file(schema="IFC4")
+    ifcopenshell.api.run("root.create_entity", ifc_file, ifc_class="IfcProject")
+    unit = ifcopenshell.api.run("unit.add_si_unit", ifc_file, unit_type="LENGTHUNIT", prefix="MILLI")
+    ifcopenshell.api.run("unit.assign_unit", ifc_file, units=[unit])
+    model = ifcopenshell.api.context.add_context(ifc_file, "Model")
+    ifcopenshell.api.context.add_context(ifc_file, "Model", "Body", "MODEL_VIEW", parent=model)
+    return ifc_file
+
+
+class TestIfcDiff:
+    def test_add_element(self):
+        ifc_file = setup_project()
+
+        new_file = ifc_file.from_string(ifc_file.to_string())
+        wall = ifcopenshell.api.root.create_entity(new_file, ifc_class="IfcWall")
+
+        ifc_diff = ifcdiff.IfcDiff(ifc_file, new_file)
+        ifc_diff.diff()
+        assert ifc_diff.added_elements == {wall.GlobalId}
+        assert ifc_diff.deleted_elements == set()
+        assert ifc_diff.change_register == {}
+
+    def test_remove_element(self):
+        ifc_file = setup_project()
+        wall = ifcopenshell.api.root.create_entity(ifc_file, ifc_class="IfcWall")
+
+        new_file = ifc_file.from_string(ifc_file.to_string())
+        wall_new = new_file.by_id(wall.id())
+        ifcopenshell.api.root.remove_product(new_file, wall_new)
+
+        ifc_diff = ifcdiff.IfcDiff(ifc_file, new_file)
+        ifc_diff.diff()
+        assert ifc_diff.added_elements == set()
+        assert ifc_diff.deleted_elements == {wall.GlobalId}
+        assert ifc_diff.change_register == {}
+
+    def test_changed_attribute(self):
+        ifc_file = setup_project()
+        wall = ifcopenshell.api.root.create_entity(ifc_file, ifc_class="IfcWall", name="Foo")
+
+        new_file = ifc_file.from_string(ifc_file.to_string())
+        wall_new = new_file.by_id(wall.id())
+        wall_new.Name = "Bar"
+
+        ifc_diff = ifcdiff.IfcDiff(ifc_file, new_file, relationships=["attributes"])
+        ifc_diff.diff()
+        assert ifc_diff.added_elements == set()
+        assert ifc_diff.deleted_elements == set()
+        assert ifc_diff.change_register == {wall.GlobalId: {"attributes_changed": True}}
+
+    def test_changed_geometry(self):
+        ifc_file = setup_project()
+        wall = ifcopenshell.api.root.create_entity(ifc_file, ifc_class="IfcWall", name="Foo")
+        context = ifcopenshell.util.representation.get_context(ifc_file, "Model", "Body", "MODEL_VIEW")
+        assert context
+        representation = ifcopenshell.api.geometry.add_slab_representation(ifc_file, context, depth=0.2)
+        ifcopenshell.api.geometry.assign_representation(ifc_file, wall, representation)
+
+        new_file = ifc_file.from_string(ifc_file.to_string())
+        extrusion = new_file.by_type("IfcExtrudedAreaSolid")[0]
+        extrusion.Depth = 500.0
+
+        ifc_diff = ifcdiff.IfcDiff(ifc_file, new_file, relationships=["geometry"])
+        ifc_diff.diff()
+        assert ifc_diff.added_elements == set()
+        assert ifc_diff.deleted_elements == set()
+        assert ifc_diff.change_register == {wall.GlobalId: {"geometry_changed": True}}