Fix tests (#1571)

* Fix plugins test
cleanup a of code

* Try fixing `test_when_animation_is_cached` test

* Lint

* Isort

* Use ascii_lowercase for random strings

* mark test_when_animation_is_cached as xfail

* Fix formatting

* Use tempdir's for doctest also

* Format

* isort

* yield tmpdir

conftest.py

@@ -0,0 +1,25 @@
+# This file is automatically picked by pytest
+# while running tests. So, that each test is
+# run on difference temporary directories and avoiding
+# errors.
+
+# If it is running Doctest the current directory
+# is changed because it also tests the config module
+# itself. If it's a normal test then it uses the
+# tempconfig to change directories.
+
+import pytest
+from _pytest.doctest import DoctestItem
+
+from manim import config, tempconfig
+
+
+@pytest.fixture(autouse=True)
+def temp_media_dir(tmpdir, monkeypatch, request):
+    if isinstance(request.node, DoctestItem):
+        monkeypatch.chdir(tmpdir)
+        yield tmpdir
+    else:
+        with tempconfig({"media_dir": str(tmpdir)}):
+            assert config.media_dir == str(tmpdir)
+            yield tmpdir

tests/conftest.py

@@ -3,8 +3,6 @@
 
 import pytest
 
-from manim import config, tempconfig
-
 
 def pytest_addoption(parser):
     parser.addoption(
@@ -53,10 +51,3 @@ def reset_cfg_file():
     yield
     with open(cfgfilepath, "w") as cfgfile:
         cfgfile.write(original)
-
-
-@pytest.fixture(autouse=True)
-def temp_media_dir(tmpdir):
-    with tempconfig({"media_dir": str(tmpdir)}):
-        assert config.media_dir == str(tmpdir)
-        yield tmpdir

tests/test_plugins/simple_scenes.py

@@ -15,13 +15,6 @@ def construct(self):
         self.play(FadeIn(a))
 
 
-class NoAllTest(Scene):
-    def construct(self):
-        assert "test_plugin" in globals()
-        a = test_plugin.NoAll()
-        self.play(FadeIn(a))
-
-
 class WithAllTest(Scene):
     def construct(self):
         assert "WithAll" in globals()