diff --git a/swh/provenance/tests/test_conflict_resolution.py b/swh/provenance/tests/test_conflict_resolution.py
new file mode 100644
--- /dev/null
+++ b/swh/provenance/tests/test_conflict_resolution.py
@@ -0,0 +1,158 @@
+# Copyright (C) 2021  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+from datetime import datetime
+from typing import List, Optional, Tuple, Union
+
+from swh.model.hashutil import hash_to_bytes
+from swh.model.model import Sha1Git
+from swh.provenance.api.server import resolve_dates, resolve_relation, resolve_revision
+from swh.provenance.interface import RelationData, RevisionData
+
+
+def test_resolve_dates() -> None:
+    items: List[Union[Tuple[Sha1Git, Optional[datetime]], Tuple[Sha1Git]]] = [
+        (hash_to_bytes("20329687bb9c1231a7e05afe86160343ad49b494"),),
+        (
+            hash_to_bytes("20329687bb9c1231a7e05afe86160343ad49b494"),
+            datetime.fromtimestamp(1000000000),
+        ),
+        (hash_to_bytes("20329687bb9c1231a7e05afe86160343ad49b494"), None),
+    ]
+    assert resolve_dates(items) == {
+        hash_to_bytes(
+            "20329687bb9c1231a7e05afe86160343ad49b494"
+        ): datetime.fromtimestamp(1000000000)
+    }
+
+
+def test_resolve_dates_keep_min() -> None:
+    items: List[Union[Tuple[Sha1Git, Optional[datetime]], Tuple[Sha1Git]]] = [
+        (
+            hash_to_bytes("20329687bb9c1231a7e05afe86160343ad49b494"),
+            datetime.fromtimestamp(1000000001),
+        ),
+        (
+            hash_to_bytes("20329687bb9c1231a7e05afe86160343ad49b494"),
+            datetime.fromtimestamp(1000000000),
+        ),
+    ]
+    assert resolve_dates(items) == {
+        hash_to_bytes(
+            "20329687bb9c1231a7e05afe86160343ad49b494"
+        ): datetime.fromtimestamp(1000000000)
+    }
+
+
+def test_resolve_revision_without_date() -> None:
+    items: List[Union[Tuple[Sha1Git, RevisionData], Tuple[Sha1Git]]] = [
+        (hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),),
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            RevisionData(
+                date=None,
+                origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8175"),
+            ),
+        ),
+    ]
+    assert resolve_revision(items) == {
+        hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"): RevisionData(
+            date=None,
+            origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8175"),
+        )
+    }
+
+
+def test_resolve_revision_without_origin() -> None:
+    items: List[Union[Tuple[Sha1Git, RevisionData], Tuple[Sha1Git]]] = [
+        (hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),),
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            RevisionData(date=datetime.fromtimestamp(1000000000), origin=None),
+        ),
+    ]
+    assert resolve_revision(items) == {
+        hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"): RevisionData(
+            date=datetime.fromtimestamp(1000000000),
+            origin=None,
+        )
+    }
+
+
+def test_resolve_revision_merge() -> None:
+    items: List[Union[Tuple[Sha1Git, RevisionData], Tuple[Sha1Git]]] = [
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            RevisionData(date=datetime.fromtimestamp(1000000000), origin=None),
+        ),
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            RevisionData(
+                date=None,
+                origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8175"),
+            ),
+        ),
+    ]
+    assert resolve_revision(items) == {
+        hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"): RevisionData(
+            date=datetime.fromtimestamp(1000000000),
+            origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8175"),
+        )
+    }
+
+
+def test_resolve_revision_keep_min_date() -> None:
+    items: List[Union[Tuple[Sha1Git, RevisionData], Tuple[Sha1Git]]] = [
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            RevisionData(
+                date=datetime.fromtimestamp(1000000000),
+                origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8174"),
+            ),
+        ),
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            RevisionData(
+                date=datetime.fromtimestamp(1000000001),
+                origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8175"),
+            ),
+        ),
+    ]
+    assert resolve_revision(items) == {
+        hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"): RevisionData(
+            date=datetime.fromtimestamp(1000000000),
+            origin=hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8175"),
+        )
+    }
+
+
+def test_resolve_relation() -> None:
+    items: List[Tuple[Sha1Git, Sha1Git, bytes]] = [
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8174"),
+            b"/path/1",
+        ),
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8174"),
+            b"/path/2",
+        ),
+        (
+            hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"),
+            hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8174"),
+            b"/path/1",
+        ),
+    ]
+    assert resolve_relation(items) == {
+        hash_to_bytes("c0d8929936631ecbcf9147be6b8aa13b13b014e4"): {
+            RelationData(
+                hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8174"), b"/path/1"
+            ),
+            RelationData(
+                hash_to_bytes("3acef14580ea7fd42840ee905c5ce2b0ef9e8174"), b"/path/2"
+            ),
+        }
+    }