Configure envlist in tox_configure

This is a cleaner method of configuring the desired envs to run,
by overriding tox's config.envlist.

There are a few things worth noting:

1. Because we override envlist directly, instead of proxying
   through the TOXENV environment variable, it eliminates an
   inconsistency where all envs run when no environments are
   detected to run, because TOXENV was set to the empty string
   and ignored.
2. Because we override envlist later, we must also check manually
   for envs passed directly into tox, so we don't override in
   that case (config.option.env).
3. To maintain backward compatibility, envs that don't exist
   in the tox.ini aren't automatically created like they are
   when using the TOXENV environment variable, so we have to
   manually add the envconfigs necessary for those.

src/tox_travis/hooks.py

@@ -17,7 +17,6 @@ def tox_addoption(parser):
         help='Exit successfully after all Travis jobs complete successfully.')
 
     if 'TRAVIS' in os.environ:
-        default_toxenv()
         pypy_version_monkeypatch()
 
 
@@ -27,4 +26,5 @@ def tox_configure(config):
     if 'TRAVIS' in os.environ:
         if config.option.travis_after:
             travis_after_monkeypatch()
+        default_toxenv(config)
         override_ignore_outcome(config)

src/tox_travis/toxenv.py

@@ -10,9 +10,9 @@
 from .utils import TRAVIS_FACTORS, parse_dict
 
 
-def default_toxenv():
-    """Default TOXENV automatically based on the Travis environment."""
-    if 'TOXENV' in os.environ:
+def default_toxenv(config):
+    """Default envlist automatically based on the Travis environment."""
+    if 'TOXENV' in os.environ or config.option.env:
         return  # Skip any processing if already set
 
     ini = py.iniconfig.IniConfig('tox.ini')
@@ -29,7 +29,40 @@ def default_toxenv():
     # Find matching envs
     matched = match_envs(declared_envs, desired_envs,
                          passthru=len(desired_factors) == 1)
-    os.environ.setdefault('TOXENV', ','.join(matched))
+
+    # Make the envconfig for undeclared matched envs
+    autogen_envconfigs(config, set(matched) - set(config.envconfigs))
+
+    config.envlist = matched
+
+
+def autogen_envconfigs(config, envs):
+    """Make the envconfigs for undeclared envs.
+
+    This is a stripped-down version of parseini.__init__ made for making
+    an envconfig.
+    """
+    prefix = 'tox' if config.toxinipath.basename == 'setup.cfg' else None
+    reader = tox.config.SectionReader("tox", config._cfg, prefix=prefix)
+    distshare_default = "{homedir}/.tox/distshare"
+    reader.addsubstitutions(toxinidir=config.toxinidir,
+                            homedir=config.homedir)
+
+    reader.addsubstitutions(toxworkdir=config.toxworkdir)
+    config.distdir = reader.getpath("distdir", "{toxworkdir}/dist")
+    reader.addsubstitutions(distdir=config.distdir)
+    config.distshare = reader.getpath("distshare", distshare_default)
+    reader.addsubstitutions(distshare=config.distshare)
+
+    # Create the undeclared envs
+    for env in envs:
+        make_envconfig = tox.config.parseini.make_envconfig
+        # Dig past the unbound method in Python 2
+        make_envconfig = getattr(make_envconfig, '__func__', make_envconfig)
+
+        section = tox.config.testenvprefix + env
+        config.envconfigs[env] = make_envconfig(
+            config, env, section, reader._subs, config)
 
 
 def get_declared_envs(ini):
@@ -205,5 +238,5 @@ def override_ignore_outcome(config):
     tox_config = py.iniconfig.IniConfig('tox.ini')
     travis_reader = tox.config.SectionReader("travis", tox_config)
     if travis_reader.getbool('unignore_outcomes', False):
-        for env in config.envlist:
-            config.envconfigs[env].ignore_outcome = False
+        for envconfig in config.envconfigs.values():
+            envconfig.ignore_outcome = False

tests/test_toxenv.py

@@ -416,7 +416,7 @@ def test_travis_ignore_outcome(self, tmpdir, monkeypatch):
         """Test ignore_outcome without setting obey_outcomes."""
         tox_ini = tox_ini_ignore_outcome
         with self.configure(
-            tmpdir, monkeypatch, tox_ini, travis_language='generic'
+            tmpdir, monkeypatch, tox_ini, travis_version='3.4'
         ):
             config = self.tox_config()
             assert config["testenv:py34"]["ignore_outcome"] == "True"
@@ -426,7 +426,7 @@ def test_travis_ignore_outcome_unignore_outcomes(self, tmpdir,
         """Test ignore_outcome setting unignore_outcomes = False."""
         tox_ini = tox_ini_ignore_outcome_unignore_outcomes
         with self.configure(
-            tmpdir, monkeypatch, tox_ini, travis_language='generic'
+            tmpdir, monkeypatch, tox_ini, travis_version='3.4'
         ):
             config = self.tox_config()
             assert config["testenv:py34"]["ignore_outcome"] == "False"
@@ -436,7 +436,7 @@ def test_travis_ignore_outcome_not_unignore_outcomes(self, tmpdir,
         """Test ignore_outcome setting unignore_outcomes = False (default)."""
         tox_ini = tox_ini_ignore_outcome_not_unignore_outcomes
         with self.configure(
-            tmpdir, monkeypatch, tox_ini, travis_language='generic'
+            tmpdir, monkeypatch, tox_ini, travis_version='3.4'
         ):
             config = self.tox_config()
             assert config["testenv:py34"]["ignore_outcome"] == "True"