Pandas to vw text format

python/tests/test_pyvw.py

@@ -2,7 +2,9 @@
 
 from vowpalwabbit import pyvw
 from vowpalwabbit.pyvw import vw
+from vowpalwabbit.pyvw import DFtoVW, SimpleLabel, Feature, Namespace, Col
 import pytest
+import pandas as pd
 
 BIT_SIZE = 18
 
@@ -344,3 +346,95 @@ def check_error_raises(type, argument):
     """
     with pytest.raises(type) as error:
         argument()
+
+def test_from_colnames_constructor():
+    df = pd.DataFrame({"y": [1], "x": [2]})
+    conv = DFtoVW.from_colnames(y="y", x=["x"], df=df)
+    lines_list = conv.process_df()
+    first_line = lines_list[0]
+    assert first_line == "1 | 2"
+
+
+def test_feature_column_renaming_and_tag():
+    df = pd.DataFrame({"idx": ["id_1"], "y": [1], "x": [2]})
+    conv = DFtoVW(
+        label=SimpleLabel(Col("y")),
+        tag=Col("idx"),
+        namespaces=Namespace([Feature(name="col_x", value=Col("x"))]),
+        df=df,
+    )
+    first_line = conv.process_df()[0]
+    assert first_line == "1 id_1| col_x:2"
+
+
+def test_feature_constant_column_with_empty_name():
+    df = pd.DataFrame({"idx": ["id_1"], "y": [1], "x": [2]})
+    conv = DFtoVW(
+        label=SimpleLabel(Col("y")),
+        tag=Col("idx"),
+        namespaces=Namespace([Feature(name="", value=2)]),
+        df=df,
+    )
+    first_line = conv.process_df()[0]
+    assert first_line == "1 id_1| :2"
+
+
+def test_feature_variable_column_name():
+    df = pd.DataFrame({"y": [1], "x": [2], "a": ["col_x"]})
+    conv = DFtoVW(
+        label=SimpleLabel(Col("y")),
+        namespaces=Namespace(Feature(name=Col("a"), value=Col("x"))),
+        df=df,
+    )
+    first_line = conv.process_df()[0]
+    assert first_line == "1 | col_x:2"
+
+
+def test_multiple_lines_conversion():
+    df = pd.DataFrame({"y": [1, -1], "x": [1, 2]})
+    conv = DFtoVW(
+        label=SimpleLabel(Col("y")),
+        namespaces=Namespace(Feature(value=Col("x"))),
+        df=df,
+    )
+    lines_list = conv.process_df()
+    assert lines_list == ["1 | 1", "-1 | 2"]
+
+
+def test_multiple_namespaces():
+    df = pd.DataFrame({"y": [1], "a": [2], "b": [3]})
+    conv = DFtoVW(
+        df=df,
+        label=SimpleLabel(Col("y")),
+        namespaces=[
+            Namespace(name="FirstNameSpace", features=Feature(Col("a"))),
+            Namespace(name="DoubleIt", value=2, features=Feature(Col("b"))),
+        ],
+    )
+    first_line = conv.process_df()[0]
+    assert first_line == "1 |FirstNameSpace 2 |DoubleIt:2 3"
+
+
+def test_without_target():
+    df = pd.DataFrame({"a": [2], "b": [3]})
+    conv = DFtoVW(
+        df=df, namespaces=Namespace([Feature(Col("a")), Feature(Col("b"))])
+    )
+    first_line = conv.process_df()[0]
+    assert first_line == "| 2 3"
+
+
+def test_absent_col_error():
+    with pytest.raises(ValueError) as value_error:
+        df = pd.DataFrame({"a": [1]})
+        conv = DFtoVW(
+            df=df,
+            label=SimpleLabel(Col("a")),
+            namespaces=Namespace(
+                [Feature(Col("a")), Feature(Col("c")), Feature("d")]
+            ),
+        )
+    expected = "In argument 'features', column(s) 'c' not found in dataframe"
+    assert expected == str(value_error.value)
+
+