ci: Skip package build on tox runs (#5210)

Building a wheel/sdist generally adds 5+ seconds to every tox run.
This is unnecessary because a built package isn't needed to run any
of the CI tasks.

Also remove the `recreate` line as it wasn't doing anything. To work
correctly, it should be defined under `[testenv]`,
not `[tox]`.

test-requirements.txt

@@ -1,5 +1,7 @@
 # Needed generally in tests
 
+-r requirements.txt
+
 # Avoid breaking change in `testpaths` treatment forced
 # test/unittests/conftest.py to be loaded by our integration-tests tox env
 # resulting in an unmet dependency issue:

tools/read-dependencies

@@ -203,7 +203,7 @@ def parse_pip_requirements(requirements_path):
     with open(requirements_path, "r") as fp:
         for line in fp:
             line = line.strip()
-            if not line or line.startswith("#"):
+            if not line or line.startswith(("#", "-r ")):
                 continue
 
             # remove pip-style markers
@@ -212,9 +212,7 @@ def parse_pip_requirements(requirements_path):
             # remove version requirements
             version_comparison = re.compile(r"[~!>=.<]+")
             if version_comparison.search(dep):
-                dep_names.append(
-                    version_comparison.split(dep)[0].strip()
-                )
+                dep_names.append(version_comparison.split(dep)[0].strip())
             else:
                 dep_names.append(dep)
     return dep_names

tox.ini

@@ -6,12 +6,12 @@ envlist =
     isort,
     mypy,
     pylint
-recreate = True
 
 [doc8]
 ignore-path-errors=doc/rtd/topics/faq.rst;D001
 
 [testenv]
+package = skip
 basepython = python3
 setenv =
     LC_ALL = en_US.utf-8