Add test for upgrading preference file

Contributes to issue CURA-4148.

plugins/VersionUpgrade/VersionUpgrade27to30/tests/TestVersionUpgrade27to30.py

@@ -0,0 +1,171 @@
+# Copyright (c) 2017 Ultimaker B.V.
+# Cura is released under the terms of the AGPLv3 or higher.
+
+import configparser #To parse the resulting config files.
+import pytest #To register tests with.
+
+import VersionUpgrade27to30 #The module we're testing.
+
+##  Creates an instance of the upgrader to test with.
+@pytest.fixture
+def upgrader():
+    return VersionUpgrade27to30.VersionUpgrade27to30()
+
+test_cfg_version_good_data = [
+    {
+        "test_name": "Simple",
+        "file_data": """[general]
+version = 1
+""",
+        "version": 1000000
+    },
+    {
+        "test_name": "Other Data Around",
+        "file_data": """[nonsense]
+life = good
+
+[general]
+version = 3
+
+[values]
+layer_height = 0.12
+infill_sparse_density = 42
+""",
+        "version": 3000000
+    },
+    {
+        "test_name": "Negative Version", #Why not?
+        "file_data": """[general]
+version = -20
+""",
+        "version": -20000000
+    },
+    {
+        "test_name": "Setting Version",
+        "file_data": """[general]
+version = 1
+[metadata]
+setting_version = 1
+""",
+        "version": 1000001
+    },
+    {
+        "test_name": "Negative Setting Version",
+        "file_data": """[general]
+version = 1
+[metadata]
+setting_version = -3
+""",
+        "version": 999997
+    }
+]
+
+##  Tests the technique that gets the version number from CFG files.
+#
+#   \param data The parametrised data to test with. It contains a test name
+#   to debug with, the serialised contents of a CFG file and the correct
+#   version number in that CFG file.
+#   \param upgrader The instance of the upgrade class to test.
+@pytest.mark.parametrize("data", test_cfg_version_good_data)
+def test_cfgVersionGood(data, upgrader):
+    version = upgrader.getCfgVersion(data["file_data"])
+    assert version == data["version"]
+
+test_cfg_version_bad_data = [
+    {
+        "test_name": "Empty",
+        "file_data": "",
+        "exception": configparser.Error #Explicitly not specified further which specific error we're getting, because that depends on the implementation of configparser.
+    },
+    {
+        "test_name": "No General",
+        "file_data": """[values]
+layer_height = 0.1337
+""",
+        "exception": configparser.Error
+    },
+    {
+        "test_name": "No Version",
+        "file_data": """[general]
+true = false
+""",
+        "exception": configparser.Error
+    },
+    {
+        "test_name": "Not a Number",
+        "file_data": """[general]
+version = not-a-text-version-number
+""",
+        "exception": ValueError
+    },
+    {
+        "test_name": "Setting Value NaN",
+        "file_data": """[general]
+version = 4
+[metadata]
+setting_version = latest_or_something
+""",
+        "exception": ValueError
+    },
+    {
+        "test_name": "Major-Minor",
+        "file_data": """[general]
+version = 1.2
+""",
+        "exception": ValueError
+    }
+]
+
+##  Tests whether getting a version number from bad CFG files gives an
+#   exception.
+#
+#   \param data The parametrised data to test with. It contains a test name
+#   to debug with, the serialised contents of a CFG file and the class of
+#   exception it needs to throw.
+#   \param upgrader The instance of the upgrader to test.
+@pytest.mark.parametrize("data", test_cfg_version_bad_data)
+def test_cfgVersionBad(data, upgrader):
+    with pytest.raises(data["exception"]):
+        upgrader.getCfgVersion(data["file_data"])
+
+test_translate_theme_data = [
+    (
+        "Original Cura theme",
+        """[general]
+version = 4
+theme = cura
+[metadata]
+setting_version = 2
+""",
+        "cura-light"
+    ),
+    (
+        "No theme",
+        """[general]
+version = 4
+[metadata]
+setting_version = 2
+""",
+        None #Indicates that the theme should be absent in the new file.
+    )
+]
+
+##  Tests whether the theme is properly translated.
+@pytest.mark.parametrize("test_name, file_data, new_theme", test_translate_theme_data)
+def test_translateTheme(test_name, file_data, new_theme, upgrader):
+    #Read old file.
+    original_parser = configparser.ConfigParser(interpolation = None)
+    original_parser.read_string(file_data)
+
+    #Perform the upgrade.
+    _, upgraded_stacks = upgrader.upgradePreferences(file_data, "<string>")
+    upgraded_stack = upgraded_stacks[0]
+    parser = configparser.ConfigParser(interpolation = None)
+    parser.read_string(upgraded_stack)
+
+    #Check whether the theme was properly translated.
+    if not new_theme:
+        assert "theme" not in parser["general"]
+    else:
+        assert "theme" in parser["general"]
+        assert parser["general"]["theme"] == new_theme