1 files changed, 92 insertions, 0 deletions
diff --git a/tests/functional/u/use/use_maxsplit_arg.py b/tests/functional/u/use/use_maxsplit_arg.py
new file mode 100644
index 000000000..396da3adc
--- /dev/null
+++ b/tests/functional/u/use/use_maxsplit_arg.py
@@ -0,0 +1,92 @@
+"""Emit a message for accessing first/last element of string.split"""
+# pylint: disable=line-too-long,missing-docstring,unsubscriptable-object,too-few-public-methods,invalid-name,redefined-builtin
+
+# Test subscripting .split()
+get_first = '1,2,3'.split(',')[0]  # [use-maxsplit-arg]
+get_last = '1,2,3'[::-1].split(',')[0]  # [use-maxsplit-arg]
+
+SEQ = '1,2,3'
+get_first = SEQ.split(',')[0]  # [use-maxsplit-arg]
+get_last = SEQ.split(',')[-1]  # [use-maxsplit-arg]
+get_first = SEQ.rsplit(',')[0]  # [use-maxsplit-arg]
+get_last = SEQ.rsplit(',')[-1]  # [use-maxsplit-arg]
+
+# Don't suggest maxsplit=1 if not accessing the first or last element
+get_mid = SEQ.split(',')[1]
+get_mid = SEQ.split(',')[-2]
+
+
+# Test varying maxsplit argument -- all these will be okay
+# ## str.split() tests
+good_split = '1,2,3'.split(sep=',', maxsplit=1)[-1]
+good_split = '1,2,3'.split(sep=',', maxsplit=1)[0]
+good_split = '1,2,3'.split(sep=',', maxsplit=2)[-1]
+good_split = '1,2,3'.split(sep=',', maxsplit=2)[0]
+good_split = '1,2,3'.split(sep=',', maxsplit=2)[1]
+
+# ## str.rsplit() tests
+good_split = '1,2,3'.rsplit(sep=',', maxsplit=1)[-1]
+good_split = '1,2,3'.rsplit(sep=',', maxsplit=1)[0]
+good_split = '1,2,3'.rsplit(sep=',', maxsplit=2)[-1]
+good_split = '1,2,3'.rsplit(sep=',', maxsplit=2)[0]
+good_split = '1,2,3'.rsplit(sep=',', maxsplit=2)[1]
+
+
+# Tests on class attributes
+class Foo():
+    class_str = '1,2,3'
+    def __init__(self):
+        self.my_str = '1,2,3'
+
+    def get_string(self) -> str:
+        return self.my_str
+
+# Class attributes
+get_first = Foo.class_str.split(',')[0]  # [use-maxsplit-arg]
+get_last = Foo.class_str.split(',')[-1]  # [use-maxsplit-arg]
+get_first = Foo.class_str.rsplit(',')[0]  # [use-maxsplit-arg]
+get_last = Foo.class_str.rsplit(',')[-1]  # [use-maxsplit-arg]
+
+get_mid = Foo.class_str.split(',')[1]
+get_mid = Foo.class_str.split(',')[-2]
+
+
+# Test with accessors
+bar = Foo()
+get_first = bar.get_string().split(',')[0]  # [use-maxsplit-arg]
+get_last = bar.get_string().split(',')[-1]  # [use-maxsplit-arg]
+
+get_mid = bar.get_string().split(',')[1]
+get_mid = bar.get_string().split(',')[-2]
+
+
+# Test with iterating over strings
+list_of_strs = ["a", "b", "c", "d", "e", "f"]
+for s in list_of_strs:
+    print(s.split(" ")[0])  # [use-maxsplit-arg]
+    print(s.split(" ")[-1])  # [use-maxsplit-arg]
+    print(s.split(" ")[-2])
+
+
+# Test warning messages (matching and replacing .split / .rsplit)
+class Bar():
+    split = '1,2,3'
+
+# Error message should show Bar.split.split(',', maxsplit=1) or Bar.split.rsplit(',', maxsplit=1)
+print(Bar.split.split(",")[0])  # [use-maxsplit-arg]
+print(Bar.split.split(",")[-1])  # [use-maxsplit-arg]
+print(Bar.split.rsplit(",")[0])  # [use-maxsplit-arg]
+print(Bar.split.rsplit(",")[-1])  # [use-maxsplit-arg]
+
+# Special cases
+a = "1,2,3".split('\n')[0]  # [use-maxsplit-arg]
+a = "1,2,3".split('split')[-1]  # [use-maxsplit-arg]
+a = "1,2,3".rsplit('rsplit')[0]  # [use-maxsplit-arg]
+
+# Test cases for false-positive reported in #4664
+# https://github.com/PyCQA/pylint/issues/4664
+source = 'A.B.C.D.E.F.G'
+i = 0
+for j in range(5):
+    print(source.split('.')[i])
+    i = i + 1