New demo module to teach developers how to hack on the BlenderBIM Add-on.

src/blenderbim/test/bim/feature/demo.feature

@@ -0,0 +1,45 @@
+# ############################################################################ #
+
+# Hey there! Welcome to the BlenderBIM Add-on code. Please feel free to reach
+# out if you have any questions or need further guidance. Happy hacking!
+
+# ############################################################################ #
+
+# This allows us to write full integration tests that test how all systems work
+# as a whole. Whilst other tests focus on portions of the software, these tests
+# simulate what happens when a user opens Blender, presses buttons, and does
+# things.
+
+# These tests read like english. You can see all the possible sentences defined
+# in test_feature.py. Most of the time, there is already a sentence defined for
+# what you want to test.
+
+@demo
+Feature: Demo
+
+# Every operator has at least one scenario associated with it to test it.
+Scenario: Demonstrate hello world
+    Given an empty IFC project
+    When I press "bim.demonstrate_hello_world"
+    # Blender doesn't have a way of testing that things are visible in the
+    # interface and layout. We can check properties, and whats in the 3D
+    # scenegraph, but not layout. There is no "DOM" like in web applications.
+    # Too bad, we can't check the results, but we still write the test, that way
+    # we can still check for errors like crashes or Python errors, like a "smoke
+    # test".
+    Then nothing happens
+
+# This operator has two scenarios because there are two possibilities of a user
+# interacting with it.
+Scenario: Demonstrate rename project - with a name provided
+    Given an empty IFC project
+    When I set "scene.BIMDemoProperties.name" to "Foobar"
+    And I press "bim.demonstrate_rename_project"
+    Then the object "IfcProject/Foobar" is an "IfcProject"
+
+# This is the other possible scenario for the rename project operator.
+Scenario: Demonstrate rename project - with no name
+    Given an empty IFC project
+    When I set "scene.BIMDemoProperties.name" to ""
+    And I press "bim.demonstrate_rename_project"
+    Then the object "IfcProject/My Project" is an "IfcProject"

src/blenderbim/test/bim/test_feature.py

@@ -209,6 +209,19 @@ def i_set_prop_to_value(prop, value):
         exec(f"bpy.context.{prop} = {value}")
 
 
+@given(parsers.parse('I set "{prop}" to ""'))
+@when(parsers.parse('I set "{prop}" to ""'))
+def i_set_prop_to_value(prop):
+    try:
+        eval(f"bpy.context.{prop}")
+    except:
+        assert False, "Property does not exist"
+    try:
+        exec(f'bpy.context.{prop} = r""')
+    except:
+        pass
+
+
 @when(parsers.parse('I am on frame "{number}"'))
 def i_am_on_frame_number(number):
     bpy.context.scene.frame_set(int(number))