Use xdist for faster multi-processing-based tests

Author: jbcoe

nle/tests/test_db.py

@@ -133,6 +133,7 @@ def conn(mockdata):
         yield conn
 
 
+@pytest.mark.usefixtures("mockdata")
 class TestDB:
     def test_conn(self, conn):
         assert conn

pyproject.toml

@@ -53,7 +53,7 @@ nle-ttyplay2 = "nle.scripts.ttyplay2:main"
 nle-read-tty = "nle.scripts.read_tty:main"
 
 [dependency-groups]
-dev = ["nle[dev]"]
+dev = ["nle[dev]", "pytest-xdist>=3.8.0"]
 
 [project.optional-dependencies]
 agent = ["torch>=1.3.1"]
@@ -115,3 +115,4 @@ before-all = "rm -rf {project}/build {project}/*.so {project}/CMakeCache.txt &&
 
 [tool.pytest.ini_options]
 testpaths = ["nle/tests"]
+addopts = "-n auto"