Merge pull request #888 from jbellister-slac/add_display_tests

TST: Add some test cases for loading python files as displays

pydm/display.py

@@ -191,7 +191,8 @@ def load_py_file(pyfile, args=None, macros=None):
         cls = module.intelclass
         if not issubclass(cls, Display):
             raise ValueError(
-                "Invalid class definition at file {}. {} does not inherit from Display. Nothing to open at this time.".format(
+                "Invalid class definition at file {}. {} does not inherit from Display. "
+                "Nothing to open at this time.".format(
                     pyfile, cls.__name__))
     else:
         classes = [obj for name, obj in inspect.getmembers(module) if
@@ -203,16 +204,12 @@ def load_py_file(pyfile, args=None, macros=None):
                     pyfile))
         if len(classes) > 1:
             warnings.warn(
-                "More than one Display class in file {}. The first occurence (in alphabetical order) will be opened: {}".format(
+                "More than one Display class in file {}. "
+                "The first occurrence (in alphabetical order) will be opened: {}".format(
                     pyfile, classes[0].__name__), RuntimeWarning, stacklevel=2)
         cls = classes[0]
 
-    try:
-        # This only works in python 3 and up.
-        module_params = inspect.signature(cls).parameters
-    except AttributeError:
-        # Works in python 2, deprecated in 3.0 and up.
-        module_params = inspect.getargspec(cls.__init__).args
+    module_params = inspect.signature(cls).parameters
 
     # Because older versions of Display may not have the args parameter or the macros parameter, we check
     # to see if it does before trying to use them.

pydm/tests/test_data/no_display_test_file.py

@@ -0,0 +1,8 @@
+# A sample test file of a python class that does not inherit from PyDM's display, but we try to load as a display anyway
+from qtpy.QtCore import QObject
+
+
+class InvalidDisplayExample(QObject):
+    """ A simple class that inherits from QObject only """
+    def __init__(self, parent=None):
+        super().__init__(parent=parent)

pydm/tests/test_data/valid_display_test_file.py

@@ -0,0 +1,28 @@
+""" This file is intended for use in Display related test files. """
+import os
+from pydm import Display
+from pydm.widgets import PyDMPushButton, PyDMLabel
+# Ensure loading of modules in the same directory works as expected when this file is loaded as a PyDM Display
+import no_display_test_file
+
+
+class DisplayExample(Display):
+    """ An example of a simple display that can be loaded by `load_py_file` in `display.py` """
+    def __init__(self, parent=None, args=None, macros=None):
+        super().__init__(parent=parent, args=args, macros=macros)
+        self.button = PyDMPushButton()
+        self.button.clicked.connect(self.delete_widget)
+
+        self.label = PyDMLabel(init_channel='TST:Val1')
+
+    def print_file(self):
+        print(f'{no_display_test_file}')
+
+    def delete_widget(self):
+        self.label.deleteLater()
+
+    def ui_filename(self):
+        return 'test.ui'
+
+    def ui_filepath(self):
+        return os.path.join(os.path.dirname(os.path.realpath(__file__)), self.ui_filename())

pydm/tests/test_display.py

@@ -1,12 +1,22 @@
 import os
 import pytest
 from pydm import Display
+from pydm.display import load_py_file
 
 # The path to the .ui file used in these tests
 test_ui_path = os.path.join(
     os.path.dirname(os.path.realpath(__file__)),
     "test_data", "test.ui")
 
+# The path to the .py files used in these tests
+no_display_test_py_path = os.path.join(
+    os.path.dirname(os.path.realpath(__file__)),
+    "test_data", "no_display_test_file.py")
+
+valid_display_test_py_path = os.path.join(
+    os.path.dirname(os.path.realpath(__file__)),
+    "test_data", "valid_display_test_file.py")
+
 
 def test_ui_filename_arg(qtbot):
     """If you supply a valid filename argument, you shouldn't get any exceptions."""
@@ -34,3 +44,39 @@ def ui_filename(self):
 
     with pytest.raises(IOError):
         my_display = TestDisplay(parent=None)
+
+
+def test_nonexistent_py_file_raises():
+    """ Load a python file that does not exist and confirm the error raised is as expected """
+    with pytest.raises(FileNotFoundError):
+        load_py_file('this_doesnt_exist.py')
+
+
+def test_doesnt_inherit_display_raises():
+    """ Load a python file that does not inherit from PyDM Display and confirm the error raised is as expected """
+    with pytest.raises(ValueError) as error_info:
+        load_py_file(no_display_test_py_path)
+    assert 'no class inheriting from Display' in str(error_info.value)
+
+
+def test_load_valid_python_display_file(qtbot):
+    """ Verify that loading a valid python only file inheriting from Display works as expected """
+    display = load_py_file(valid_display_test_py_path)
+    qtbot.addWidget(display)
+
+    # Confirm that the file loaded everything as expected
+    assert display.loaded_file() == valid_display_test_py_path
+    assert display.ui_filename() == 'test.ui'
+    assert display.macros() == {}
+    assert display.previous_display is None
+    assert display.next_display is None
+
+
+def test_load_python_file_with_macros(qtbot):
+    """ Attempt to add macros to the display while loading the file """
+    macros = {'MACRO_1': 7, 'MACRO_2': 'test_string'}
+    display = load_py_file(valid_display_test_py_path, macros=macros)
+    qtbot.addWidget(display)
+    assert display.loaded_file() == valid_display_test_py_path
+    assert display.ui_filename() == 'test.ui'
+    assert display.macros() == {'MACRO_1': 7, 'MACRO_2': 'test_string'}