diff --git a/README.md b/README.md
index 7d5b7a9..c473c7e 100644
--- a/README.md
+++ b/README.md
@@ -56,30 +56,31 @@ For example, if upstream suggests installing test dependencies with
     %pyproject_buildrequires -r -x testing
 
 For projects that specify test requirements in their [tox] configuration,
-these can be added using the `-t` flag followed by the tox environment.
-The recommended tox environment (such as `py37` assuming the Fedora's Python version is 3.7)
+these can be added using the `-t` flag (default tox environment)
+or the `-e` flag followed by the tox environment.
+The default tox environment (such as `py37` assuming the Fedora's Python version is 3.7)
 is available in the `%{toxenv}` macro.
 For example, if upstream suggests running the tests on Python 3.7 with `tox -e py37`,
 the test deps would be generated by:
 
     %generate_buildrequires
-    %pyproject_buildrequires -t %{toxenv}
+    %pyproject_buildrequires -t
 
 If upstream uses a custom derived environment, such as `py37-unit`, use:
 
-    %pyproject_buildrequires -t %{toxenv}-unit
+    %pyproject_buildrequires -e %{toxenv}-unit
 
 Or specify more environments if needed:
 
-    %pyproject_buildrequires -t %{toxenv}-unit,%{toxenv}-integration
+    %pyproject_buildrequires -e %{toxenv}-unit,%{toxenv}-integration
 
-The `-t` option redefines `%{toxenv}` for further reuse.
+The `-e` option redefines `%{toxenv}` for further reuse.
 Use `%{default_toxenv}` to get the default value.
 
 Note that `-t` implies `-r`, because tox normally assumes the package is installed
 including all the runtime dependencies.
 
-The `-t` option uses [tox-current-env]'s `--print-deps-only` behind the scenes.
+The `-t`/`-e` option uses [tox-current-env]'s `--print-deps-to-file` behind the scenes.
 
 [tox]: https://tox.readthedocs.io/
 [tox-current-env]: https://github.com/fedora-python/tox-current-env/
@@ -122,8 +123,8 @@ Or (note the two sequential `--`s):
 
     %tox -- -- --flag-for-posargs
 
-**Warning:** This macro assumes you have used `%pyproject_buildrequires -t` in
-`%generate_buildrequires`. If not, you need to add:
+**Warning:** This macro assumes you have used `%pyproject_buildrequires -t` or `-e`
+in `%generate_buildrequires`. If not, you need to add:
 
     BuildRequires: python3dist(tox-current-env)
 
@@ -141,7 +142,5 @@ Some valid Python version specifiers are not supported.
 
 The `-x` flag does not yet support multiple (comma-separated) extras.
 
-The `-t` flag does not yet support being used without a value.
-
 [PEP 517]: https://www.python.org/dev/peps/pep-0517/
 [PEP 518]: https://www.python.org/dev/peps/pep-0518/
diff --git a/macros.pyproject b/macros.pyproject
index 0a4f37b..1d2fc43 100644
--- a/macros.pyproject
+++ b/macros.pyproject
@@ -20,8 +20,8 @@ fi
 %default_toxenv py%{python3_version_nodots}
 %toxenv %{default_toxenv}
 
-%pyproject_buildrequires(rx:t:) %{expand:\\\
-%{-t:%{expand:%global toxenv %{-t*}}}
+%pyproject_buildrequires(rxte:) %{expand:\\\
+%{-e:%{expand:%global toxenv %{-e*}}}
 echo 'python3-devel'
 echo 'python3dist(packaging)'
 echo 'python3dist(pip) >= 19'
@@ -29,7 +29,7 @@ echo 'python3dist(pytoml)'
 # setuptools assumes no pre-existing dist-info
 rm -rfv *.dist-info/
 if [ -f %{__python3} ]; then
-  %{__python3} -I %{_rpmconfigdir}/redhat/pyproject_buildrequires.py %{?**}
+  RPM_TOXENV=%{toxenv} %{__python3} -I %{_rpmconfigdir}/redhat/pyproject_buildrequires.py %{?**}
 fi
 }
 
diff --git a/pyproject-rpm-macros.spec b/pyproject-rpm-macros.spec
index 1a31c0a..4fb50d7 100644
--- a/pyproject-rpm-macros.spec
+++ b/pyproject-rpm-macros.spec
@@ -35,7 +35,7 @@ BuildRequires: python3dist(packaging)
 BuildRequires: python3dist(pytoml)
 BuildRequires: python3dist(pip)
 BuildRequires: python3dist(setuptools)
-BuildRequires: python3dist(tox-current-env)
+BuildRequires: python3dist(tox-current-env) >= 0.0.2
 BuildRequires: python3dist(wheel)
 %endif
 
diff --git a/pyproject_buildrequires.py b/pyproject_buildrequires.py
index 943f6d3..e9eddce 100644
--- a/pyproject_buildrequires.py
+++ b/pyproject_buildrequires.py
@@ -1,3 +1,4 @@
+import os
 import sys
 import importlib
 import argparse
@@ -176,13 +177,18 @@ def generate_run_requirements(backend, requirements):
 
 
 def generate_tox_requirements(toxenv, requirements):
-    requirements.extend(['tox-current-env >= 0.0.2'], source='tox itself')
+    requirements.add('tox-current-env >= 0.0.2', source='tox itself')
+    requirements.check(source='tox itself')
     with tempfile.NamedTemporaryFile('r') as depfile:
-        with hook_call():
-            subprocess.run(
-                ['tox', '--print-deps-to-file', depfile.name, '-qre', toxenv],
-                check=True,
-            )
+        r = subprocess.run(
+            ['tox', '--print-deps-to-file', depfile.name, '-qre', toxenv],
+            check=True,
+            encoding='utf-8',
+            stdout=subprocess.PIPE,
+            stderr=subprocess.STDOUT,
+        )
+        if r.stdout:
+            print_err(r.stdout)
         requirements.extend(depfile.read().splitlines(),
                             source=f'tox --print-deps-only: {toxenv}')
 
@@ -222,7 +228,12 @@ def main(argv):
         help='Generate run-time requirements',
     )
     parser.add_argument(
-        '-t', '--toxenv', metavar='TOXENVS',
+        '-e', '--toxenv', metavar='TOXENVS', default=None,
+        help=('specify tox environments'
+              '(implies --tox)'),
+    )
+    parser.add_argument(
+        '-t', '--tox', action='store_true',
         help=('generate test tequirements from tox environment '
               '(implies --runtime)'),
     )
@@ -235,8 +246,15 @@ def main(argv):
     )
 
     args = parser.parse_args(argv)
+
     if args.toxenv:
+        args.tox = True
+
+    if args.tox:
         args.runtime = True
+        args.toxenv = (args.toxenv or os.getenv('RPM_TOXENV') or
+                       f'py{sys.version_info.major}{sys.version_info.minor}')
+
     if args.extras and not args.runtime:
         print_err('-x (--extras) are only useful with -r (--runtime)')
         exit(1)
@@ -255,7 +273,7 @@ def main(argv):
             toxenv=args.toxenv,
             extras=args.extras,
         )
-    except Exception as e:
+    except Exception:
         # Log the traceback explicitly (it's useful debug info)
         traceback.print_exc()
         exit(1)
diff --git a/testcases.yaml b/testcases.yaml
index b751d1f..2c90bd0 100644
--- a/testcases.yaml
+++ b/testcases.yaml
@@ -257,6 +257,8 @@ Tox depndencies:
   freeze_output: |
     setuptools==50
     wheel==1
+    tox==3.5.3
+    tox-current-env==0.0.2
   toxenv: py3
   setup.py: |
     from setuptools import setup
diff --git a/tests/python-pluggy.spec b/tests/python-pluggy.spec
index c77ff13..449c23d 100644
--- a/tests/python-pluggy.spec
+++ b/tests/python-pluggy.spec
@@ -28,7 +28,7 @@ Summary:        %{summary}
 
 
 %generate_buildrequires
-%pyproject_buildrequires -t %{toxenv}-pytestrelease
+%pyproject_buildrequires -e %{toxenv}-pytestrelease
 
 
 %build
diff --git a/tests/python-pytest.spec b/tests/python-pytest.spec
index d6ad7ab..0567c18 100644
--- a/tests/python-pytest.spec
+++ b/tests/python-pytest.spec
@@ -27,7 +27,7 @@ py.test provides simple, yet powerful testing for Python.
 
 
 %generate_buildrequires
-%pyproject_buildrequires -r -x testing
+%pyproject_buildrequires -x testing -t
 
 
 %build
@@ -40,8 +40,7 @@ py.test provides simple, yet powerful testing for Python.
 %check
 # Only run one test (which uses a test-only dependency, hypothesis).
 # (Unfortunately, some other tests still fail.)
-export PYTHONPATH=%{buildroot}%{python3_sitelib}
-%{__python3} -m pytest -k metafunc
+%tox -- -- -k metafunc
 
 
 %files -n python3-%{pypi_name}