tests: Fix ansible_python_interpreter & discovered_interpreter_python tests on macOS

Should account for fiddling in mitogen.parent.Connection._first_stage() and
symlinks. I won't be surprised if it breaks again soon and often.

mitogen/parent.py

@@ -1409,6 +1409,9 @@ class Connection(object):
     #     their respective values.
     #   * CONTEXT_NAME must be prefixed with the name of the Python binary in
     #     order to allow virtualenvs to detect their install prefix.
+    #
+    # macOS tweaks for Python 2.7 must be kept in sync with the the Ansible
+    # module test_echo_module, used by the integration tests.
     #   * macOS <= 10.14 (Darwin <= 18) install an unreliable Python version
     #     switcher as /usr/bin/python, which introspects argv0. To workaround
     #     it we redirect attempts to call /usr/bin/python with an explicit
@@ -1417,7 +1420,8 @@ class Connection(object):
     #     do something slightly different. The Python executable is patched to
     #     perform an extra execvp(). I don't fully understand the details, but
     #     setting PYTHON_LAUNCHED_FROM_WRAPPER=1 avoids it.
-    #   * macOS 13.x (Darwin 22?) may remove python 2.x entirely.
+    #   * macOS 12.3+ (Darwin 21.4+, Monterey) doesn't ship Python.
+    #     https://developer.apple.com/documentation/macos-release-notes/macos-12_3-release-notes#Python
     #
     # Locals:
     #   R: read side of interpreter stdin.

tests/ansible/integration/interpreter_discovery/ansible_2_8_tests.yml

@@ -37,6 +37,7 @@
             vars:
               ansible_python_interpreter: auto
             test_echo_module:
+              facts_copy: "{{ ansible_facts }}"
             register: echoout
 
           # can't test this assertion:
@@ -44,11 +45,15 @@
           # because Mitogen's ansible_python_interpreter is a connection-layer configurable that
           # "must be extracted during each task execution to form the complete connection-layer configuration".
           # Discovery won't be reran though; the ansible_python_interpreter is read from the cache if already discovered
-          - assert:
+          - name: assert discovered python matches invoked python
+            assert:
               that:
               - auto_out.ansible_facts.discovered_interpreter_python is defined
-              - echoout.running_python_interpreter == auto_out.ansible_facts.discovered_interpreter_python
-              fail_msg: auto_out={{auto_out}} echoout={{echoout}}
+              - auto_out.ansible_facts.discovered_interpreter_python == echoout.discovered_python.as_seen
+              - echoout.discovered_python.resolved == echoout.running_python.sys.executable.resolved
+              fail_msg:
+                - "auto_out: {{ auto_out }}"
+                - "echoout: {{ echoout }}"
 
 
         - name: test that auto_legacy gives a dep warning when /usr/bin/python present but != auto result
@@ -128,7 +133,8 @@
         - name: ensure modules can't set discovered_interpreter_X or ansible_X_interpreter
           block:
           - test_echo_module:
-              facts:
+              facts_copy: "{{ ansible_facts }}"
+              facts_to_override:
                 ansible_discovered_interpreter_bogus: from module
                 discovered_interpreter_bogus: from_module
                 ansible_bogus_interpreter: from_module

tests/ansible/lib/modules/test_echo_module.py

@@ -9,28 +9,51 @@
 from __future__ import absolute_import, division, print_function
 __metaclass__ = type
 
+import os
 import platform
 import sys
 from ansible.module_utils.basic import AnsibleModule
 
 
 def main():
-    result = dict(changed=False)
-
     module = AnsibleModule(argument_spec=dict(
-        facts=dict(type=dict, default={})
+        facts_copy=dict(type=dict, default={}),
+        facts_to_override=dict(type=dict, default={})
     ))
 
-    result['ansible_facts'] = module.params['facts']
     # revert the Mitogen OSX tweak since discover_interpreter() doesn't return this info
-    if sys.platform == 'darwin' and sys.executable != '/usr/bin/python':
-        if int(platform.release()[:2]) < 19:
-            sys.executable = sys.executable[:-3]
-        else:
+    # NB This must be synced with mitogen.parent.Connection.get_boot_command()
+    if sys.modules.get('mitogen') and sys.platform == 'darwin':
+        darwin_major = int(platform.release().partition('.')[0])
+        if darwin_major < 19 and sys.executable == '/usr/bin/python2.7':
+            sys.executable = '/usr/bin/python'
+        if darwin_major in (20, 21) and sys.version_info[:2] == (2, 7):
             # only for tests to check version of running interpreter -- Mac 10.15+ changed python2
             # so it looks like it's /usr/bin/python but actually it's /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python
             sys.executable = "/usr/bin/python"
-    result['running_python_interpreter'] = sys.executable
+
+    facts_copy = module.params['facts_copy']
+    discovered_interpreter_python = facts_copy['discovered_interpreter_python']
+    result = {
+        'changed': False,
+        'ansible_facts': module.params['facts_to_override'],
+        'discovered_and_running_samefile': os.path.samefile(
+            os.path.realpath(discovered_interpreter_python),
+            os.path.realpath(sys.executable),
+        ),
+        'discovered_python': {
+            'as_seen': discovered_interpreter_python,
+            'resolved': os.path.realpath(discovered_interpreter_python),
+        },
+        'running_python': {
+            'sys': {
+                'executable': {
+                    'as_seen': sys.executable,
+                    'resolved': os.path.realpath(sys.executable),
+                },
+            },
+        },
+    }
 
     module.exit_json(**result)