keep additional environments config order #921

5 files changed, 57 insertions, 10 deletions

diff --git a/changelog/921.feature.rst b/changelog/921.feature.rst
new file mode 100644
index 00000000..7a061b95
--- /dev/null
+++ b/changelog/921.feature.rst
@@ -0,0 +1 @@
+keep additional environments config order when listing them - by :user:`gaborbernat`
diff --git a/src/tox/config.py b/src/tox/config.py
index e9f55c99..a7e62d52 100755
--- a/src/tox/config.py
+++ b/src/tox/config.py
@@ -10,6 +10,7 @@ import string
 import sys
 import uuid
 import warnings
+from collections import OrderedDict
 from fnmatch import fnmatchcase
 from subprocess import list2cmdline
 
@@ -783,7 +784,7 @@ class Config(object):
     """Global Tox config object."""
 
     def __init__(self, pluginmanager, option, interpreters, parser):
-        self.envconfigs = {}
+        self.envconfigs = OrderedDict()
         """Mapping envname -> envconfig"""
         self.invocationcwd = py.path.local()
         self.interpreters = interpreters
@@ -1110,25 +1111,28 @@ class ParseIni(object):
         env_list = _split_env(env_str)
 
         # collect section envs
-        all_envs = set(env_list) - {"ALL"}
+        all_envs = OrderedDict((i, None) for i in env_list)
+        if "ALL" in all_envs:
+            all_envs.pop("ALL")
         for section in self._cfg:
             if section.name.startswith(testenvprefix):
-                all_envs.add(section.name[len(testenvprefix) :])
+                all_envs[section.name[len(testenvprefix) :]] = None
         if not all_envs:
-            all_envs.add("python")
+            all_envs["python"] = None
 
         package_env = config.isolated_build_env
         if config.isolated_build is True and package_env in all_envs:
-            all_envs.remove(package_env)
+            all_envs.pop(package_env)
 
         if not env_list or "ALL" in env_list:
-            env_list = sorted(all_envs)
+            env_list = list(all_envs.keys())
 
         if config.isolated_build is True and package_env in env_list:
             msg = "isolated_build_env {} cannot be part of envlist".format(package_env)
             raise tox.exception.ConfigError(msg)
 
-        return env_list, all_envs
+        all_env_list = list(all_envs.keys())
+        return env_list, all_env_list
 
 
 def _split_env(env):
diff --git a/src/tox/session.py b/src/tox/session.py
index 5ac0c7d3..97e5da19 100644
--- a/src/tox/session.py
+++ b/src/tox/session.py
@@ -621,7 +621,7 @@ class Session:
         env_conf = self.config.envconfigs  # this contains all environments
         default = self.config.envlist  # this only the defaults
         ignore = {self.config.isolated_build_env}.union(default)
-        extra = sorted(e for e in env_conf if e not in ignore) if all_envs else []
+        extra = [e for e in env_conf if e not in ignore] if all_envs else []
 
         if description:
             self.report.line("default environments:")
diff --git a/tests/unit/session/test_list_env.py b/tests/unit/session/test_list_env.py
index 8ccee897..e48e532a 100644
--- a/tests/unit/session/test_list_env.py
+++ b/tests/unit/session/test_list_env.py
@@ -150,3 +150,45 @@ def test_listenvs_packaging_excluded(cmd, initproj):
     result = cmd("-a")
     expected = ["py36", "py27", "py34", "pypi", "docs", "notincluded"]
     assert result.outlines == expected, result.outlines
+
+
+def test_listenvs_all_extra_definition_order_decreasing(cmd, initproj):
+    initproj(
+        "listenvs_all",
+        filedefs={
+            "tox.ini": """
+        [tox]
+        envlist=py36
+
+        [testenv:b]
+        changedir = whatever
+
+        [testenv:a]
+        changedir = docs
+        """
+        },
+    )
+    result = cmd("-a")
+    expected = ["py36", "b", "a"]
+    assert result.outlines == expected
+
+
+def test_listenvs_all_extra_definition_order_increasing(cmd, initproj):
+    initproj(
+        "listenvs_all",
+        filedefs={
+            "tox.ini": """
+        [tox]
+        envlist=py36
+
+        [testenv:a]
+        changedir = whatever
+
+        [testenv:b]
+        changedir = docs
+        """
+        },
+    )
+    result = cmd("-a")
+    expected = ["py36", "a", "b"]
+    assert result.outlines == expected
diff --git a/tests/unit/test_config.py b/tests/unit/test_config.py
index d4d940f7..8b5d2285 100644
--- a/tests/unit/test_config.py
+++ b/tests/unit/test_config.py
@@ -1833,9 +1833,9 @@ class TestGlobalOptions:
         assert config.envlist == ["py35", "py36"]
         monkeypatch.setenv("TOXENV", "ALL")
         config = newconfig([], inisource)
-        assert config.envlist == ["py27", "py35", "py36"]
+        assert config.envlist == ["py36", "py35", "py27"]
         config = newconfig(["-eALL"], inisource)
-        assert config.envlist == ["py27", "py35", "py36"]
+        assert config.envlist == ["py36", "py35", "py27"]
         config = newconfig(["-espam"], inisource)
         assert config.envlist == ["spam"]