first commit

.venv/Lib/site-packages/pandas/tests/reshape/concat/test_invalid.py

@@ -0,0 +1,56 @@
+from io import StringIO
+
+import numpy as np
+import pytest
+
+from pandas import (
+    DataFrame,
+    concat,
+    read_csv,
+)
+import pandas._testing as tm
+
+
+class TestInvalidConcat:
+    def test_concat_invalid(self):
+
+        # trying to concat a ndframe with a non-ndframe
+        df1 = tm.makeCustomDataframe(10, 2)
+        for obj in [1, {}, [1, 2], (1, 2)]:
+
+            msg = (
+                f"cannot concatenate object of type '{type(obj)}'; "
+                "only Series and DataFrame objs are valid"
+            )
+            with pytest.raises(TypeError, match=msg):
+                concat([df1, obj])
+
+    def test_concat_invalid_first_argument(self):
+        df1 = tm.makeCustomDataframe(10, 2)
+        msg = (
+            "first argument must be an iterable of pandas "
+            'objects, you passed an object of type "DataFrame"'
+        )
+        with pytest.raises(TypeError, match=msg):
+            concat(df1)
+
+    def test_concat_generator_obj(self):
+        # generator ok though
+        concat(DataFrame(np.random.rand(5, 5)) for _ in range(3))
+
+    def test_concat_textreader_obj(self):
+        # text reader ok
+        # GH6583
+        data = """index,A,B,C,D
+                  foo,2,3,4,5
+                  bar,7,8,9,10
+                  baz,12,13,14,15
+                  qux,12,13,14,15
+                  foo2,12,13,14,15
+                  bar2,12,13,14,15
+               """
+
+        with read_csv(StringIO(data), chunksize=1) as reader:
+            result = concat(reader, ignore_index=True)
+        expected = read_csv(StringIO(data))
+        tm.assert_frame_equal(result, expected)