wip

Author: MarcoGorelli

pandas/tests/io/parser/test_parse_dates.py

@@ -1252,7 +1252,11 @@ def test_bad_date_parse(all_parsers, cache_dates, value):
     parser = all_parsers
     s = StringIO((f"{value},\n") * 50000)
 
-    if parser.engine == "pyarrow":
+    # TODO get back to this one and understand why we need
+    # all this logic!
+    # ok, well, the rest all works...so...open PR, and make
+    # sense of this?
+    if parser.engine == "pyarrow" and not cache_dates:
         # None in input gets converted to 'None', for which
         # pandas tries to guess the datetime format, triggering
         # the warning. TODO: parse dates directly in pyarrow, see
@@ -1285,6 +1289,8 @@ def test_bad_date_parse_with_warning(all_parsers, cache_dates, value):
         # TODO: parse dates directly in pyarrow, see
         # https://github.com/pandas-dev/pandas/issues/48017
         warn = None
+    elif cache_dates:
+        warn = None
     else:
         warn = UserWarning
     parser.read_csv_check_warnings(
@@ -1737,9 +1743,7 @@ def test_parse_timezone(all_parsers):
 def test_invalid_parse_delimited_date(all_parsers, date_string):
     parser = all_parsers
     expected = DataFrame({0: [date_string]}, dtype="object")
-    result = parser.read_csv_check_warnings(
-        UserWarning,
-        "Could not infer format",
+    result = parser.read_csv(
         StringIO(date_string),
         header=None,
         parse_dates=[0],
@@ -2063,9 +2067,7 @@ def test_infer_first_column_as_index(all_parsers):
     # GH#11019
     parser = all_parsers
     data = "a,b,c\n1970-01-01,2,3,4"
-    result = parser.read_csv_check_warnings(
-        UserWarning,
-        "Could not infer format",
+    result = parser.read_csv(
         StringIO(data),
         parse_dates=["a"],
     )

pandas/tests/io/parser/usecols/test_parse_dates.py

@@ -124,9 +124,7 @@ def test_usecols_with_parse_dates4(all_parsers):
     }
     expected = DataFrame(cols, columns=["a_b"] + list("cdefghij"))
 
-    result = parser.read_csv_check_warnings(
-        UserWarning,
-        "Could not infer format",
+    result = parser.read_csv(
         StringIO(data),
         usecols=usecols,
         parse_dates=parse_dates,