Rework File.spoiler to synchronise with the filename

Co-authored-by: Danny <Rapptz@users.noreply.github.com>

tests/test_files.py

@@ -0,0 +1,129 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2015-present Rapptz
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+from __future__ import annotations
+
+from io import BytesIO
+
+import discord
+
+
+FILE = BytesIO()
+
+
+def test_file_with_no_name():
+    f = discord.File('.gitignore')
+    assert f.filename == '.gitignore'
+
+
+def test_io_with_no_name():
+    f = discord.File(FILE)
+    assert f.filename == 'untitled'
+
+
+def test_file_with_name():
+    f = discord.File('.gitignore', 'test')
+    assert f.filename == 'test'
+
+
+def test_io_with_name():
+    f = discord.File(FILE, 'test')
+    assert f.filename == 'test'
+
+
+def test_file_with_no_name_and_spoiler():
+    f = discord.File('.gitignore', spoiler=True)
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_with_spoiler_name_and_implicit_spoiler():
+    f = discord.File('.gitignore', 'SPOILER_.gitignore')
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_with_spoiler_name_and_spoiler():
+    f = discord.File('.gitignore', 'SPOILER_.gitignore', spoiler=True)
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_with_spoiler_name_and_not_spoiler():
+    f = discord.File('.gitignore', 'SPOILER_.gitignore', spoiler=False)
+    assert f.filename == '.gitignore'
+    assert f.spoiler == False
+
+
+def test_file_with_name_and_double_spoiler_and_implicit_spoiler():
+    f = discord.File('.gitignore', 'SPOILER_SPOILER_.gitignore')
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_with_name_and_double_spoiler_and_spoiler():
+    f = discord.File('.gitignore', 'SPOILER_SPOILER_.gitignore', spoiler=True)
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_with_name_and_double_spoiler_and_not_spoiler():
+    f = discord.File('.gitignore', 'SPOILER_SPOILER_.gitignore', spoiler=False)
+    assert f.filename == '.gitignore'
+    assert f.spoiler == False
+
+
+def test_file_with_spoiler_with_overriding_name_not_spoiler():
+    f = discord.File('.gitignore', spoiler=True)
+    f.filename = '.gitignore'
+    assert f.filename == '.gitignore'
+    assert f.spoiler == False
+
+
+def test_file_with_spoiler_with_overriding_name_spoiler():
+    f = discord.File('.gitignore', spoiler=True)
+    f.filename = 'SPOILER_.gitignore'
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_not_spoiler_with_overriding_name_not_spoiler():
+    f = discord.File('.gitignore')
+    f.filename = '.gitignore'
+    assert f.filename == '.gitignore'
+    assert f.spoiler == False
+
+
+def test_file_not_spoiler_with_overriding_name_spoiler():
+    f = discord.File('.gitignore')
+    f.filename = 'SPOILER_.gitignore'
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True
+
+
+def test_file_not_spoiler_with_overriding_name_double_spoiler():
+    f = discord.File('.gitignore')
+    f.filename = 'SPOILER_SPOILER_.gitignore'
+    assert f.filename == 'SPOILER_.gitignore'
+    assert f.spoiler == True