unittest: Remove dependence on sys.exc_info.

This is not included by default in most builds, and isn't necessary for
this module anyway.

Also fix the local variable shadowing the traceback module in _capture_exc.

Added test for both (works on CPython and MicroPython).

Version bump to 0.10.2.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

python-stdlib/unittest/manifest.py

@@ -1,3 +1,3 @@
-metadata(version="0.10.1")
+metadata(version="0.10.2")
 
 package("unittest")

python-stdlib/unittest/tests/test_exception.py

@@ -0,0 +1,13 @@
+import unittest
+
+
+def broken_func():
+    raise ValueError("uh oh!")
+
+
+def test_func():
+    broken_func()
+
+
+if __name__ == "__main__":
+    unittest.main()

python-stdlib/unittest/unittest/__init__.py

@@ -332,12 +332,12 @@ class TestResult:
         return self
 
 
-def _capture_exc(exc, traceback):
+def _capture_exc(exc, exc_traceback):
     buf = io.StringIO()
     if hasattr(sys, "print_exception"):
         sys.print_exception(exc, buf)
     elif traceback is not None:
-        traceback.print_exception(None, exc, traceback, file=buf)
+        traceback.print_exception(None, exc, exc_traceback, file=buf)
     return buf.getvalue()
 
 
@@ -402,7 +402,7 @@ def _run_suite(c, test_result: TestResult, suite_name=""):
             test_result.skipped.append((name, c, reason))
         except Exception as ex:
             _handle_test_exception(
-                current_test=(name, c), test_result=test_result, exc_info=sys.exc_info()
+                current_test=(name, c), test_result=test_result, exc_info=(type(ex), ex, None)
             )
             # Uncomment to investigate failure in detail
             # raise