Add a dependency group for our new test dependency.

And remove the minor duplicate install of the package which was
happening.

Author: Julian

noxfile.py

@@ -60,8 +60,7 @@ def tests(session, installable):
     """
     env = dict(JSON_SCHEMA_TEST_SUITE=str(ROOT / "json"))
 
-    session.install("virtue", installable)
-    session.install("jsonpath-ng", installable)
+    session.install("--group=test", installable)
 
     if session.posargs and session.posargs[0] == "coverage":
         if len(session.posargs) > 1 and session.posargs[1] == "github":

pyproject.toml

@@ -78,6 +78,9 @@ Tidelift = "https://tidelift.com/subscription/pkg/pypi-jsonschema?utm_source=pyp
 Changelog = "https://github.com/python-jsonschema/jsonschema/blob/main/CHANGELOG.rst"
 Source = "https://github.com/python-jsonschema/jsonschema"
 
+[dependency-groups]
+test = ["virtue", "jsonpath-ng"]
+
 [tool.hatch.metadata.hooks.fancy-pypi-readme]
 content-type = "text/x-rst"