Fix coverage on MacOS (#254)

fixes #234

Author: deathaxe

README.md

@@ -9,16 +9,10 @@ It runs unittest testcases on local machines and via Github Actions.
 It also supports testing syntax_test files for the new [sublime-syntax](https://www.sublimetext.com/docs/3/syntax.html) 
 format and sublime-color-scheme files.
 
-
 ## Sublime Text 4
 
 Sublime Text 4 is now supported and testing works for Python 3.8 packages.
 
-> [!NOTE]
->
-> coverage 7.x is currently skipped for python 3.8 plugins on MacOS,
-> because ST4 is missing a required core module.
-
 ## Preparation
 
 1. Install [UnitTesting](https://github.com/SublimeText/UnitTesting) via Package Control.

unittesting/unit.py

@@ -8,13 +8,6 @@
 from unittest import TestSuite
 from unittest import TextTestRunner
 
-try:
-    if sys.platform == "darwin":
-        raise ImportError("unsupported")
-    import coverage
-except Exception:
-    coverage = False
-
 from .base import BaseUnittestingCommand
 from .base import DONE_MESSAGE
 from .core import DeferrableTestCase
@@ -24,6 +17,31 @@
 from .utils import reload_package
 from .utils import StdioSplitter
 
+try:
+    import coverage
+
+    # ST4 does not ship `_sysconfigdata__darwin_darwin` module, required by
+    # coverage 7.x on MacOS, which causes `sysconfig.add_paths()` to fail.
+    # On other OSs it returns potentially unwanted paths outside of ST ecosystem.
+    # Thus monkey patch it.
+    try:
+        import coverage.inorout
+
+        def __add_third_party_paths(paths):
+            """Return $data/Lib/pythonXY as 3rd-party path."""
+            libs_path = os.path.join(
+                os.path.dirname(sublime.packages_path()),
+                "Lib",
+                "python{}{}".format(sys.version_info.major, sys.version_info.minor)
+            )
+            paths.add(libs_path)
+
+        coverage.inorout.add_third_party_paths = __add_third_party_paths
+    except:
+        pass
+except Exception:
+    coverage = False
+
 
 class UnitTestingCommand(BaseUnittestingCommand):