Headless gui tests (#61)

* Fix gui tests for headless server

* Add display before import statements

* Fix gui init for callback tests

* Factor out transparent colour setting

.github/workflows/pytest-unit-tests.yml

@@ -27,9 +27,11 @@ jobs:
         conda install pip
         pip install -e .
     - name: Install test dependencies
+    # sudo apt-get install xvfb x11-utils gnumeric required for gui tests running in headless mode
       run: |
         conda install pip
         pip install -r dev-requirements.txt
+        sudo apt-get install xvfb x11-utils gnumeric
     - name: Test with pytest
       working-directory: tests
       run: |

desktop_shop/gui/init.py

@@ -13,10 +13,18 @@
 from desktop_shop.gui.views import views
 
 
+def _set_transparent_colour():
+    # this apparently fails on linux for no particular reason
+    try:
+        gui.root.wm_attributes("-transparentcolor", "purple")
+    except tk.TclError:
+        pass
+
+
 def init_root():
     """Initialises and configures tk root"""
     gui.root.title("OfflineShop")
-    gui.root.wm_attributes("-transparentcolor", "purple")
+    _set_transparent_colour()
     gui.root.config(bg=config.BG)
     for _ in range(21):
         gui.root.add_row(30)

dev-requirements.in

@@ -6,6 +6,7 @@ tox
 # Testing.
 pytest
 pytest-cov
+pyvirtualdisplay
 
 # Type checking.
 mypy

dev-requirements.txt

@@ -22,10 +22,17 @@ click==8.0.4
     # via
     #   black
     #   mkdocs
+colorama==0.4.6
+    # via
+    #   click
+    #   pytest
+    #   tox
 coverage[toml]==6.3.2
     # via pytest-cov
 distlib==0.3.4
     # via virtualenv
+exceptiongroup==1.1.0
+    # via pytest
 filelock==3.6.0
     # via
     #   tox
@@ -50,7 +57,9 @@ griffe==0.12.6
 idna==3.3
     # via requests
 importlib-metadata==4.11.1
-    # via mkdocs
+    # via
+    #   markdown
+    #   mkdocs
 iniconfig==1.1.1
     # via pytest
 isort==5.10.1
@@ -97,12 +106,12 @@ mkdocs-literate-nav==0.5.0
 mkdocs-material==8.2.7
     # via -r dev-requirements.in
 mkdocs-material-extensions==1.0.3
-    # via mkdocs-material
-mkdocstrings[python]==0.19.0
     # via
     #   -r dev-requirements.in
     #   mkdocstrings-python
 mkdocstrings-python==0.6.3
+    # via mkdocs-material
+mkdocstrings[python]==0.19.0
     # via mkdocstrings
 mypy==0.982
     # via -r dev-requirements.in
@@ -149,6 +158,8 @@ pytest-cov==4.0.0
     # via -r dev-requirements.in
 python-dateutil==2.8.2
     # via ghp-import
+pyvirtualdisplay==3.0
+    # via -r dev-requirements.in
 pyyaml==6.0
     # via
     #   mkdocs
@@ -167,11 +178,18 @@ six==1.16.0
 soupsieve==2.3.1
     # via beautifulsoup4
 tomli==2.0.1
-    # via coverage
+    # via
+    #   black
+    #   coverage
+    #   mypy
+    #   pytest
+    #   tox
 tox==3.27.1
     # via -r dev-requirements.in
 typing-extensions==4.1.1
-    # via mypy
+    # via
+    #   black
+    #   mypy
 urllib3==1.26.8
     # via requests
 virtualenv==20.13.1

tests/unit/gui/callbacks_test.py

@@ -7,9 +7,21 @@
 
 # pylint: disable=missing-function-docstring
 
+import os
+import sys
+
 import sqlite3
 import pytest
 
+# fix for headless machines
+display = None  # pylint: disable=invalid-name
+if sys.platform.startswith("linux") and os.environ.get("DISPLAY") is None:
+    from pyvirtualdisplay import Display
+
+    display = Display(visible=False, size=(100, 60))
+    display.start()
+
+# pylint: disable=wrong-import-position
 from desktop_shop.gui import callbacks, init
 from desktop_shop import gui
 from desktop_shop.user import UserSignUpData
@@ -21,6 +33,11 @@
 ITERATIONS = 1
 
 
+def teardown():
+    if display is not None:
+        display.stop()
+
+
 def init_gui(monkeypatch: pytest.MonkeyPatch):
     generate_data.generate(
         TEST_DB,

tests/unit/gui/init_test.py

@@ -1,25 +1,28 @@
 # -*- coding: utf-8 -*-
 """Smoke tests for gui init function"""
+
+# pylint: disable=missing-function-docstring, missing-class-docstring
+
 from collections import namedtuple
 import os
 import sys
 
 import pytest
 
+from desktop_shop.gui.views import checkout
+
+
+# pylint: disable=wrong-import-position
 from desktop_shop import database, server
+from desktop_shop import gui
+from desktop_shop.gui import init
 
 Product = namedtuple("Product", ["id", "name", "price"])
 
 
 def test_gui_init(monkeypatch):
-    if sys.platform.startswith("linux") and os.environ.get("DISPLAY") is None:  # FIXME
-        pytest.skip("Tkinter cannot be initialised on headless server")
-
-    from desktop_shop import gui
-    from desktop_shop.gui import init
-    from desktop_shop.gui.views import views
-
-    Product = namedtuple("Product", ["id", "name", "price"])
+    if sys.platform.startswith("linux") and os.environ.get("DISPLAY") is None:
+        pytest.skip()
 
     def fake_products_query(*_, **__):
         return [
@@ -35,10 +38,8 @@ def fake_products_query(*_, **__):
 
 
 def test_checkout_view():
-    if sys.platform.startswith("linux") and os.environ.get("DISPLAY") is None:  # FIXME
-        pytest.skip("Tkinter cannot be initialised on headless server")
-
-    from desktop_shop import gui
+    if sys.platform.startswith("linux") and os.environ.get("DISPLAY") is None:
+        pytest.skip()
 
     class MonkeyPatch:
         def __enter__(self):
@@ -50,9 +51,10 @@ def __enter__(self):
         def __exit__(self, *_):
             server.query_product_data_from_product_table_by_product_ids = self.func
 
+    checkout_view = checkout.View.create(gui.root, init.init_builder())
     with MonkeyPatch():
         gui.app.data["cart"] = ["0"]
-        gui.app["checkout"].init_checkout()
+        checkout_view.init_checkout()
 
         # call again to cover code for the case of an already-built checkout View
-        gui.app["checkout"].init_checkout()
+        checkout_view.init_checkout()