feat: generate label map on the backend (#21124)

tests/unit_tests/pandas_postprocessing/test_flatten.py

@@ -156,3 +156,22 @@ def test_flat_integer_column_name():
             }
         )
     )
+
+
+def test_escape_column_name():
+    index = pd.to_datetime(["2021-01-01", "2021-01-02", "2021-01-03"])
+    index.name = "__timestamp"
+    columns = pd.MultiIndex.from_arrays(
+        [
+            ["level1,value1", "level1,value2", "level1,value3"],
+            ["level2, value1", "level2, value2", "level2, value3"],
+        ],
+        names=["level1", "level2"],
+    )
+    df = pd.DataFrame(index=index, columns=columns, data=1)
+    assert list(pp.flatten(df).columns.values) == [
+        "__timestamp",
+        "level1\\,value1" + FLAT_COLUMN_SEPARATOR + "level2\\, value1",
+        "level1\\,value2" + FLAT_COLUMN_SEPARATOR + "level2\\, value2",
+        "level1\\,value3" + FLAT_COLUMN_SEPARATOR + "level2\\, value3",
+    ]

tests/unit_tests/pandas_postprocessing/test_utils.py

@@ -0,0 +1,30 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from superset.utils.pandas_postprocessing import escape_separator, unescape_separator
+
+
+def test_escape_separator():
+    assert escape_separator(r" hell \world ") == r" hell \world "
+    assert unescape_separator(r" hell \world ") == r" hell \world "
+
+    escape_string = escape_separator("hello, world")
+    assert escape_string == r"hello\, world"
+    assert unescape_separator(escape_string) == "hello, world"
+
+    escape_string = escape_separator("hello,world")
+    assert escape_string == r"hello\,world"
+    assert unescape_separator(escape_string) == "hello,world"