add tests from ask

Author: ravinkohli

test/test_data/test_utils.py

@@ -1,17 +1,33 @@
-from typing import Mapping
+import warnings
+from typing import List, Mapping
 
 import numpy as np
 
+import pandas as pd
+
 import pytest
 
 from sklearn.datasets import fetch_openml
 
+from scipy.sparse import csr_matrix, spmatrix
+
+from autoPyTorch.constants import (
+    BINARY,
+    CLASSIFICATION_TASKS,
+    CONTINUOUS,
+    MULTICLASS,
+    MULTICLASSMULTIOUTPUT,
+    CONTINUOUSMULTIOUTPUT,
+    TABULAR_REGRESSION,
+    TABULAR_CLASSIFICATION,
+)
 from autoPyTorch.data.utils import (
     default_dataset_compression_arg,
     get_dataset_compression_mapping,
     megabytes,
     reduce_dataset_size_if_too_large,
     reduce_precision,
+    subsample,
     validate_dataset_compression_arg
 )
 from autoPyTorch.utils.common import subsampler
@@ -37,6 +53,102 @@ def test_reduce_dataset_if_too_large(openmlid, as_frame, n_samples):
     assert megabytes(X_converted) < megabytes(X)
 
 
+@pytest.mark.parametrize("X", [np.asarray([[1, 1, 1]] * 30)])
+@pytest.mark.parametrize("x_type", [list, np.ndarray, csr_matrix, pd.DataFrame])
+@pytest.mark.parametrize(
+    "y, task, output",
+    [
+        (np.asarray([0] * 15 + [1] * 15), TABULAR_CLASSIFICATION, BINARY),
+        (np.asarray([0] * 10 + [1] * 10 + [2] * 10), TABULAR_CLASSIFICATION, MULTICLASS),
+        (np.asarray([[1, 0, 1]] * 30), TABULAR_CLASSIFICATION, MULTICLASSMULTIOUTPUT),
+        (np.asarray([1.0] * 30), TABULAR_REGRESSION, CONTINUOUS),
+        (np.asarray([[1.0, 1.0, 1.0]] * 30), TABULAR_REGRESSION, CONTINUOUSMULTIOUTPUT),
+    ],
+)
+@pytest.mark.parametrize("y_type", [list, np.ndarray, pd.DataFrame, pd.Series])
+@pytest.mark.parametrize("random_state", [0])
+@pytest.mark.parametrize("sample_size", [0.25, 0.5, 5, 10])
+def test_subsample_validity(X, x_type, y, y_type, random_state, sample_size, task, output):
+    """Asserts the validity of the function with all valid types
+    We want to make sure that `subsample` works correctly with all the types listed
+    as x_type and y_type.
+    We also want to make sure it works with all kinds of target types.
+    The output should maintain the types, and subsample the correct amount.
+    (test adapted from autosklearn)
+    """
+    assert len(X) == len(y)  # Make sure our test data is correct
+
+    if y_type == pd.Series and output in [
+        MULTICLASSMULTIOUTPUT,
+        CONTINUOUSMULTIOUTPUT,
+    ]:
+        # We can't have a pd.Series with multiple values as it's 1 dimensional
+        pytest.skip("Can't have pd.Series as y when task is n-dimensional")
+
+    # Convert our data to its given x_type or y_type
+    def convert(arr, objtype):
+        if objtype == np.ndarray:
+            return arr
+        elif objtype == list:
+            return arr.tolist()
+        else:
+            return objtype(arr)
+
+    X = convert(X, x_type)
+    y = convert(y, y_type)
+
+    # Subsample the data, ignoring any warnings
+    with warnings.catch_warnings():
+        warnings.simplefilter("ignore")
+        X_sampled, y_sampled = subsample(
+            X,
+            y=y,
+            random_state=random_state,
+            sample_size=sample_size,
+            is_classification=task in CLASSIFICATION_TASKS,
+        )
+
+    # Function to get the type of an obj
+    def dtype(obj):
+        if isinstance(obj, List):
+            if isinstance(obj[0], List):
+                return type(obj[0][0])
+            else:
+                return type(obj[0])
+
+        elif isinstance(obj, pd.DataFrame):
+            return obj.dtypes
+
+        else:
+            return obj.dtype
+
+    # Check that the types of X remain the same after subsampling
+    if isinstance(X, pd.DataFrame):
+        # Dataframe can have multiple types, one per column
+        assert list(dtype(X_sampled)) == list(dtype(X))
+    else:
+        assert dtype(X_sampled) == dtype(X)
+
+    # Check that the types of y remain the same after subsampling
+    if isinstance(y, pd.DataFrame):
+        assert list(dtype(y_sampled)) == list(dtype(y))
+    else:
+        assert dtype(y_sampled) == dtype(y)
+
+    # Function to get the size of an object
+    def size(obj):
+        if isinstance(obj, spmatrix):  # spmatrix doesn't support __len__
+            return obj.shape[0] if obj.shape[0] > 1 else obj.shape[1]
+        else:
+            return len(obj)
+
+    # check the right amount of samples were taken
+    if sample_size < 1:
+        assert size(X_sampled) == int(sample_size * size(X))
+    else:
+        assert size(X_sampled) == sample_size
+
+
 def test_validate_dataset_compression_arg():
 
     data_compression_args = validate_dataset_compression_arg({}, 10)