diff --git a/pyproject.toml b/pyproject.toml
index c43e7fa..9d4a8d2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,9 +39,7 @@ warn_return_any = true
 warn_unused_configs = true
 disallow_untyped_defs = true
 
-[tool.mypy.overrides]      
-module = "tests.*"
-disallow_untyped_defs = false
+exclude = ["^tests/"]
 
 [tool.ruff]
 line-length = 110
diff --git a/src/floatmatcher/results.py b/src/floatmatcher/results.py
new file mode 100644
index 0000000..a9cfa4d
--- /dev/null
+++ b/src/floatmatcher/results.py
@@ -0,0 +1,36 @@
+# results.py: output object of matchup
+
+import numpy as np
+import xarray as xr 
+
+from dataclasses import dataclass
+from numpy.typing import NDArray
+from .pointset import PointSet
+
+
+@dataclass
+class MatchupResult:
+    values:      dict[str, NDArray[np.float64]]
+    distance_km: NDArray[np.float64]
+    time_delta:  NDArray[np.float64]
+    valid:       NDArray[np.bool_]
+    points:      PointSet
+
+    def to_dataset(self) -> xr.Dataset:
+        """
+        Reinject the colocalized values into the dataset
+        The source Dataset travels inside the PointSet
+        """
+        ds = self.points.origin_ds
+        dim = self.points.origin_dim
+        if ds is None or dim is None:
+            raise ValueError(
+                "Cannot reinject: these points have no origin dataset "
+                "(they came from raw arrays). Use the MatchupResult directly."
+            )
+
+        out = ds.copy()
+        for k, v in self.values.items():
+            out[f"{k}_coloc"] = (dim, v)
+
+        return out
diff --git a/tests/test_results.py b/tests/test_results.py
new file mode 100644
index 0000000..992ba86
--- /dev/null
+++ b/tests/test_results.py
@@ -0,0 +1,68 @@
+# tests/test_results.py
+import numpy as np
+import pytest
+import xarray as xr
+
+from floatmatcher.results import MatchupResult
+from floatmatcher.pointset import PointSet
+
+
+@pytest.fixture
+def result():
+    """ MatchupResult object - 3 profiles """
+    ds = xr.Dataset(
+        {"LONGITUDE": (("N_PROF",), np.array([-40.0, -30.0, -20.0])),
+         "LATITUDE": (("N_PROF",), np.array([35.0, 36.0, 37.0])),
+         "TIME": (("N_PROF",), np.array(["2018-01-03", "2018-01-01", "2018-01-02"],
+                                        dtype="datetime64[ns]"))},
+        coords={"N_PROF": np.array([10, 11, 12])},
+    )
+    points = PointSet(
+        lon=ds["LONGITUDE"].values,
+        lat=ds["LATITUDE"].values,
+        time=ds["TIME"].values,
+        origin_dim="N_PROF",
+        origin_ds=ds,
+    )
+    return MatchupResult(
+        values={"dummy_variable": np.array([280.0, 281.0, np.nan])},
+        distance_km=np.array([1.0, 2.0, np.nan]),
+        time_delta=np.array([0.1, 0.2, np.nan]),
+        valid=np.array([True, True, False]),
+        points=points,
+    )
+
+# @pytest.fixture
+# def argo_like_ds():
+#     return xr.Dataset(
+#         {"LONGITUDE": (("N_PROF",), np.array([-40.0, -30.0, -20.0])),
+#          "LATITUDE": (("N_PROF",), np.array([35.0, 36.0, 37.0])),
+#          "TIME": (("N_PROF",), np.array(["2018-01-03", "2018-01-01", "2018-01-02"],
+#                                         dtype="datetime64[ns]"))},
+#         coords={"N_PROF": np.array([10, 11, 12])},
+#     )
+
+
+# ---------- to_dataset ----------
+
+def test_to_dataset_adds_coloc_variable(result):
+    out = result.to_dataset()
+    assert out["dummy_variable_coloc"].dims == ("N_PROF",)
+    assert out["dummy_variable_coloc"].sel(N_PROF=10) == 280.0
+
+
+def test_to_dataset_does_not_mutate_the_source(result):
+    result.to_dataset()
+    assert "dummy_variable_coloc" not in result.points.origin_ds.data_vars
+
+
+def test_to_dataset_without_provenance_raises():
+    """Raw-array points carry no dataset, so they cannot be reinjected."""
+    points = PointSet([-45.0, -44.0, -43.0], [32.0, 33.0, 34.0],
+                      np.array(["2015-01-01", "2015-01-02", "2015-01-03"],
+                               dtype="datetime64[ns]"))
+    res = MatchupResult(values={"dummy_variable": np.zeros(3)},
+                        distance_km=np.zeros(3), time_delta=np.zeros(3),
+                        valid=np.ones(3, bool), points=points)
+    with pytest.raises(ValueError):
+        res.to_dataset()