bpo-13337: Add ignore flag to doctest

Lib/doctest.py

@@ -63,6 +63,7 @@ def _test():
     'REPORT_ONLY_FIRST_FAILURE',
     'REPORTING_FLAGS',
     'FAIL_FAST',
+    'IGNORE_CASE',
     # 1. Utility Functions
     # 2. Example & DocTest
     'Example',
@@ -139,13 +140,15 @@ def register_optionflag(name):
 ELLIPSIS = register_optionflag('ELLIPSIS')
 SKIP = register_optionflag('SKIP')
 IGNORE_EXCEPTION_DETAIL = register_optionflag('IGNORE_EXCEPTION_DETAIL')
+IGNORE_CASE = register_optionflag('IGNORE_CASE')
 
 COMPARISON_FLAGS = (DONT_ACCEPT_TRUE_FOR_1 |
                     DONT_ACCEPT_BLANKLINE |
                     NORMALIZE_WHITESPACE |
                     ELLIPSIS |
                     SKIP |
-                    IGNORE_EXCEPTION_DETAIL)
+                    IGNORE_EXCEPTION_DETAIL |
+                    IGNORE_CASE)
 
 REPORT_UDIFF = register_optionflag('REPORT_UDIFF')
 REPORT_CDIFF = register_optionflag('REPORT_CDIFF')
@@ -1607,12 +1610,22 @@ def check_output(self, want, got, optionflags):
         if got == want:
             return True
 
+        # Ignore case if flag
+        # Lowercase got and want
+        true_line = "True\n"
+        false_line = "False\n"
+        if (optionflags & IGNORE_CASE):
+            got = got.lower()
+            want = want.lower()
+            true_line = "true\n"
+            false_line = "false\n"
+
         # The values True and False replaced 1 and 0 as the return
         # value for boolean comparisons in Python 2.3.
         if not (optionflags & DONT_ACCEPT_TRUE_FOR_1):
-            if (got,want) == ("True\n", "1\n"):
+            if (got, want) == (true_line, "1\n"):
                 return True
-            if (got,want) == ("False\n", "0\n"):
+            if (got, want) == (false_line, "0\n"):
                 return True
 
         # <BLANKLINE> can be used as a special sequence to signify a

Lib/test/test_doctest.py

@@ -1314,6 +1314,12 @@ def optionflags(): r"""
     ...                 # doctest: +NORMALIZE_WHITESPACE
     [0,    1, ...,   18,    19]
 
+The IGNORE_CASE flag causes the test runner to ignore case when
+matching the expected output to the actual output
+    >>> print("Hello World") # doctest: +IGNORE_CASE
+    hello world
+
+
 The SKIP flag causes an example to be skipped entirely.  I.e., the
 example is not run.  It can be useful in contexts where doctest
 examples serve as both documentation and test cases, and an example

Misc/NEWS.d/next/Library/2020-11-29-00-38-32.bpo-13337.rSk6U7.rst

@@ -0,0 +1 @@
+Adds an `ignore_case` flag to the `doctest` library.