Make PyTest create a temporary directory to run tests in, so we don't fill up the source directory with output

Author: rpep

tests/conftest.py

@@ -0,0 +1,8 @@
+import os
+import pytest
+import tempfile
+
+@pytest.fixture(scope="session", autouse=True)
+def config():
+    tmpdir = tempfile.mkdtemp(suffix='fidimag-tests')
+    os.chdir(tmpdir)