build/pkgs/sagelib/src/tox.ini: Update tests and instructions

build/pkgs/sagelib/src/tox.ini

@@ -1,10 +1,10 @@
-# First pip-install tox:
+# First install tox:
 #
-#   ./sage -pip install tox
+#   ./sage -i tox
 #
 # To build and test in the tox environment:
 #
-# ./sage -sh -c '(cd build/pkgs/sagelib/src && tox -v -v)'
+# ./sage -sh -c '(cd build/pkgs/sagelib/src && tox -v -v -v)'
 #
 # To test interactively:
 #
@@ -29,7 +29,7 @@ commands =
     # Beware of the treacherous non-src layout. "./sage/" shadows the install sage package.
     python -c 'import sys; "" in sys.path and sys.path.remove(""); import sage.all; print(sage.all.__file__)'
 
-    # FIXME: The following loads sage-env, which loads the wrong Python.
+    # We check that the "sage" script invokes the correct Python.
     sage -c 'import sys; print("sys.path =", sys.path); import sage.all; print(sage.all.__file__)'
 
-    sage -t --all
+    sage -t -p --all