From e24b6b03886a36461af3381637a33fd8de6bee06 Mon Sep 17 00:00:00 2001
From: Christoph Buelter <christoph.buelter@myshopradio.de>
Date: Thu, 5 Dec 2019 13:56:45 +0100
Subject: [PATCH] Change -k EXPRESSION matching to be case-insensitive

---
 src/_pytest/mark/legacy.py | 10 +++++++++-
 testing/test_collection.py | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/_pytest/mark/legacy.py b/src/_pytest/mark/legacy.py
index 3721e3b02..651288cb8 100644
--- a/src/_pytest/mark/legacy.py
+++ b/src/_pytest/mark/legacy.py
@@ -57,7 +57,15 @@ class KeywordMapping:
         return cls(mapped_names)
 
     def __getitem__(self, subname):
-        for name in self._names:
+        """Return whether subname is included within stored names.
+
+        The string inclusion check is case-insensitive.
+
+        """
+        subname = subname.lower()
+        names = [name.lower() for name in self._names]
+
+        for name in names:
             if subname in name:
                 return True
         return False
diff --git a/testing/test_collection.py b/testing/test_collection.py
index 624e9dd4e..fcbfcf5fb 100644
--- a/testing/test_collection.py
+++ b/testing/test_collection.py
@@ -809,6 +809,40 @@ class TestNodekeywords:
         reprec = testdir.inline_run("-k repr")
         reprec.assertoutcome(passed=1, failed=0)
 
+    def test_keyword_matching_is_case_insensitive_by_default(self, testdir):
+        """Check that selection via -k EXPRESSION is case-insensitive.
+
+        Since markers are also added to the node keywords, they too can
+        be matched without having to think about case sensitivity.
+
+        """
+        testdir.makepyfile(
+            """
+            import pytest
+
+            def test_sPeCiFiCToPiC_1():
+                assert True
+
+            class TestSpecificTopic_2:
+                def test(self):
+                    assert True
+
+            @pytest.mark.sPeCiFiCToPic_3
+            def test():
+                assert True
+
+            @pytest.mark.sPeCiFiCToPic_4
+            class Test:
+                def test(self):
+                    assert True
+
+        """
+        )
+        num_all_tests_passed = 4
+        for expression in ("specifictopic", "SPECIFICTOPIC", "SpecificTopic"):
+            reprec = testdir.inline_run("-k " + expression)
+            reprec.assertoutcome(passed=num_all_tests_passed, failed=0)
+
 
 COLLECTION_ERROR_PY_FILES = dict(
     test_01_failure="""