feat: add easier initialization to DataSet (#4864)

* feat: enhance DataSet class with improved constructor and methods for better data handling

- Added custom constructor to support various input formats including lists of Data objects, dictionaries, and existing DataFrames.
- Introduced methods `add_row` and `add_rows` for adding single or multiple rows to the DataSet.
- Updated docstrings and examples for clarity and usability.
- Ensured compatibility with pandas DataFrame operations while preserving Data object structures.

* test: add comprehensive tests for DataSet initialization and row operations

* feat: add DataSet class to schema module

* refactor: simplify DataSet initialization and improve data validation

src/backend/tests/unit/schema/test_schema_data_set.py

@@ -17,13 +17,13 @@ def sample_data_objects() -> list[Data]:
 @pytest.fixture
 def sample_dataset(sample_data_objects) -> DataSet:
     """Fixture providing a sample DataSet instance."""
-    return DataSet.from_data_list(sample_data_objects)
+    return DataSet(sample_data_objects)
 
 
 def test_from_data_list_basic():
     """Test basic functionality of from_data_list."""
     data_objects = [Data(data={"name": "John", "age": 30}), Data(data={"name": "Jane", "age": 25})]
-    dataset = DataSet.from_data_list(data_objects)
+    dataset = DataSet(data_objects)
 
     assert isinstance(dataset, DataSet)
     assert isinstance(dataset, pd.DataFrame)
@@ -35,7 +35,7 @@ def test_from_data_list_basic():
 
 def test_from_data_list_empty():
     """Test from_data_list with empty input."""
-    dataset = DataSet.from_data_list([])
+    dataset = DataSet([])
     assert isinstance(dataset, DataSet)
     assert len(dataset) == 0
 
@@ -46,7 +46,7 @@ def test_from_data_list_missing_fields():
         Data(data={"name": "John", "age": 30}),
         Data(data={"name": "Jane", "city": "Boston"}),  # Missing age
     ]
-    dataset = DataSet.from_data_list(data_objects)
+    dataset = DataSet(data_objects)
 
     assert isinstance(dataset, DataSet)
     assert set(dataset.columns) == {"name", "age", "city"}
@@ -60,7 +60,7 @@ def test_from_data_list_nested_data():
         Data(data={"name": "John", "address": {"city": "New York", "zip": "10001"}}),
         Data(data={"name": "Jane", "address": {"city": "Boston", "zip": "02108"}}),
     ]
-    dataset = DataSet.from_data_list(data_objects)
+    dataset = DataSet(data_objects)
 
     assert isinstance(dataset, DataSet)
     assert isinstance(dataset["address"][0], dict)
@@ -123,7 +123,7 @@ def test_dataset_pandas_operations(sample_dataset):
 def test_dataset_with_null_values():
     """Test handling of null values in DataSet."""
     data_objects = [Data(data={"name": "John", "age": None}), Data(data={"name": None, "age": 25})]
-    dataset = DataSet.from_data_list(data_objects)
+    dataset = DataSet(data_objects)
 
     assert pd.isna(dataset.iloc[0]["age"])
     assert pd.isna(dataset.iloc[1]["name"])
@@ -148,7 +148,7 @@ def test_dataset_type_preservation():
             }
         )
     ]
-    dataset = DataSet.from_data_list(data_objects)
+    dataset = DataSet(data_objects)
     result = dataset.to_data_list()
 
     assert isinstance(result[0].data["int_val"], int)
@@ -157,3 +157,143 @@ def test_dataset_type_preservation():
     assert isinstance(result[0].data["bool_val"], bool)
     assert isinstance(result[0].data["list_val"], list)
     assert isinstance(result[0].data["dict_val"], dict)
+
+
+def test_add_row_with_dict(sample_dataset):
+    """Test adding a single row using a dictionary."""
+    new_row = {"name": "Alice", "age": 28, "city": "Seattle"}
+    result = sample_dataset.add_row(new_row)
+
+    assert isinstance(result, DataSet)
+    assert len(result) == len(sample_dataset) + 1
+    assert result.iloc[-1]["name"] == "Alice"
+    assert result.iloc[-1]["age"] == 28
+    assert result.iloc[-1]["city"] == "Seattle"
+
+
+def test_add_row_with_data_object(sample_dataset):
+    """Test adding a single row using a Data object."""
+    new_row = Data(data={"name": "Alice", "age": 28, "city": "Seattle"})
+    result = sample_dataset.add_row(new_row)
+
+    assert isinstance(result, DataSet)
+    assert len(result) == len(sample_dataset) + 1
+    assert result.iloc[-1]["name"] == "Alice"
+    assert result.iloc[-1]["age"] == 28
+    assert result.iloc[-1]["city"] == "Seattle"
+
+
+def test_add_rows_with_dicts(sample_dataset):
+    """Test adding multiple rows using dictionaries."""
+    new_rows = [{"name": "Alice", "age": 28, "city": "Seattle"}, {"name": "Charlie", "age": 32, "city": "Portland"}]
+    result = sample_dataset.add_rows(new_rows)
+
+    assert isinstance(result, DataSet)
+    assert len(result) == len(sample_dataset) + 2
+    assert result.iloc[-2]["name"] == "Alice"
+    assert result.iloc[-1]["name"] == "Charlie"
+
+
+def test_add_rows_with_data_objects(sample_dataset):
+    """Test adding multiple rows using Data objects."""
+    new_rows = [
+        Data(data={"name": "Alice", "age": 28, "city": "Seattle"}),
+        Data(data={"name": "Charlie", "age": 32, "city": "Portland"}),
+    ]
+    result = sample_dataset.add_rows(new_rows)
+
+    assert isinstance(result, DataSet)
+    assert len(result) == len(sample_dataset) + 2
+    assert result.iloc[-2]["name"] == "Alice"
+    assert result.iloc[-1]["name"] == "Charlie"
+
+
+def test_add_rows_mixed_types(sample_dataset):
+    """Test adding multiple rows using a mix of dictionaries and Data objects."""
+    new_rows = [
+        {"name": "Alice", "age": 28, "city": "Seattle"},
+        Data(data={"name": "Charlie", "age": 32, "city": "Portland"}),
+    ]
+    result = sample_dataset.add_rows(new_rows)
+
+    assert isinstance(result, DataSet)
+    assert len(result) == len(sample_dataset) + 2
+    assert result.iloc[-2]["name"] == "Alice"
+    assert result.iloc[-1]["name"] == "Charlie"
+
+
+def test_init_with_data_objects():
+    """Test initialization with Data objects."""
+    data_objects = [Data(data={"name": "John", "age": 30}), Data(data={"name": "Jane", "age": 25})]
+    dataset = DataSet(data_objects)
+
+    assert isinstance(dataset, DataSet)
+    assert len(dataset) == 2
+    assert list(dataset.columns) == ["name", "age"]
+    assert dataset.iloc[0]["name"] == "John"
+    assert dataset.iloc[1]["age"] == 25
+
+
+def test_init_with_dicts():
+    """Test initialization with dictionaries."""
+    data_dicts = [{"name": "John", "age": 30}, {"name": "Jane", "age": 25}]
+    dataset = DataSet(data_dicts)
+
+    assert isinstance(dataset, DataSet)
+    assert len(dataset) == 2
+    assert list(dataset.columns) == ["name", "age"]
+    assert dataset.iloc[0]["name"] == "John"
+    assert dataset.iloc[1]["age"] == 25
+
+
+def test_init_with_dict_of_lists():
+    """Test initialization with a dictionary of lists."""
+    data = {"name": ["John", "Jane"], "age": [30, 25]}
+    dataset = DataSet(data)
+
+    assert isinstance(dataset, DataSet)
+    assert len(dataset) == 2
+    assert list(dataset.columns) == ["name", "age"]
+    assert dataset.iloc[0]["name"] == "John"
+    assert dataset.iloc[1]["age"] == 25
+
+
+def test_init_with_pandas_dataframe():
+    """Test initialization with a pandas DataFrame."""
+    test_df = pd.DataFrame({"name": ["John", "Jane"], "age": [30, 25]})
+    dataset = DataSet(test_df)
+
+    assert isinstance(dataset, DataSet)
+    assert len(dataset) == 2
+    assert list(dataset.columns) == ["name", "age"]
+    assert dataset.iloc[0]["name"] == "John"
+    assert dataset.iloc[1]["age"] == 25
+
+
+def test_init_with_none():
+    """Test initialization with None."""
+    dataset = DataSet(None)
+    assert isinstance(dataset, DataSet)
+    assert len(dataset) == 0
+
+
+def test_init_with_invalid_list():
+    """Test initialization with invalid list items."""
+    invalid_data = [
+        {"name": "John", "age": 30},
+        Data(data={"name": "Jane", "age": 25}),  # Mixed types should fail
+    ]
+    with pytest.raises(ValueError, match="List items must be either all Data objects or all dictionaries"):
+        DataSet(invalid_data)
+
+
+def test_init_with_kwargs():
+    """Test initialization with additional kwargs."""
+    data = {"name": ["John", "Jane"], "age": [30, 25]}
+    dataset = DataSet(data=data, index=["a", "b"])
+
+    assert isinstance(dataset, DataSet)
+    assert len(dataset) == 2
+    assert list(dataset.index) == ["a", "b"]
+    assert dataset.loc["a"]["name"] == "John"
+    assert dataset.loc["b"]["age"] == 25