Server endpoint for surfacing discrepancies (#2026)

* Server endpoint for surfacing discrepacies

* PR feedback: update return model

* Tests for batch comparison discrepancies

* PR feedback: simplify dict init

server/api/jurisdictions.py

@@ -1,4 +1,4 @@
-from collections import Counter
+from collections import Counter, defaultdict
 import logging
 from typing import Dict, List, Optional, Mapping, cast as typing_cast
 import enum
@@ -727,3 +727,86 @@ def get_discrepancy_counts_by_jurisdiction(election: Election):
             for jurisdiction in election.jurisdictions
         }
     )
+
+
+DiscrepanciesByJurisdiction = Dict[str, Dict[str, Dict[str, Dict[str, Dict[str, int]]]]]
+# DiscrepanciesByJurisdiction = {
+#     jurisdictionID: {
+#         batchName: {
+#             contestID: {
+#                 reportedVotes:  {choiceID: int},
+#                 auditedVotes:   {choiceID: int},
+#                 discrepancies:  {choiceID: int},
+#     }
+# }
+
+
+@api.route("/election/<election_id>/discrepancy", methods=["GET"])
+@restrict_access([UserType.AUDIT_ADMIN])
+def get_discrepancies_by_jurisdiction(election: Election):
+    current_round = get_current_round(election)
+    if not current_round:
+        raise Conflict("Audit not started")
+
+    discrepancies_by_jurisdiction: DiscrepanciesByJurisdiction = {}
+
+    if election.audit_type == AuditType.BATCH_COMPARISON:
+        discrepancies_by_jurisdiction = (
+            get_batch_comparison_audit_discrepancies_by_jurisdiction(
+                election, current_round.id
+            )
+        )
+    else:
+        raise Conflict("Discrepancies are only implemented for batch comparison audits")
+
+    return jsonify(discrepancies_by_jurisdiction)
+
+
+def get_batch_comparison_audit_discrepancies_by_jurisdiction(
+    election: Election, round_id: str
+) -> DiscrepanciesByJurisdiction:
+    discrepancies_by_jurisdiction: DiscrepanciesByJurisdiction = defaultdict(
+        lambda: defaultdict(dict)
+    )
+
+    # TODO: Add support for combined batches
+    batch_keys_in_round = set(
+        SampledBatchDraw.query.filter_by(round_id=round_id)
+        .join(Batch)
+        .join(Jurisdiction)
+        .with_entities(Jurisdiction.name, Batch.name)
+        .all()
+    )
+    jurisdiction_name_to_id = dict(
+        Jurisdiction.query.filter_by(election_id=election.id).with_entities(
+            Jurisdiction.name, Jurisdiction.id
+        )
+    )
+
+    for contest in list(election.contests):
+        audited_batch_results = sampled_batch_results(
+            contest, include_non_rla_batches=True
+        )
+        reported_batch_results = batch_tallies(contest)
+
+        for batch_key, audited_batch_result in audited_batch_results.items():
+            if batch_key not in batch_keys_in_round:
+                continue
+
+            audited_contest_result = audited_batch_result[contest.id]
+            reported_contest_result = reported_batch_results[batch_key][contest.id]
+            vote_deltas = batch_vote_deltas(
+                reported_contest_result, audited_contest_result
+            )
+            if not vote_deltas:
+                continue
+
+            jurisdiction_name, batch_name = batch_key
+            jurisdiction_id = jurisdiction_name_to_id[jurisdiction_name]
+            discrepancies_by_jurisdiction[jurisdiction_id][batch_name][contest.id] = {
+                "reportedVotes": reported_contest_result,
+                "auditedVotes": audited_contest_result,
+                "discrepancies": vote_deltas,
+            }
+
+    return discrepancies_by_jurisdiction

server/tests/api/test_jurisdictions.py

@@ -429,3 +429,38 @@ def test_discrepancy_counts_before_audit_launch(
             }
         ]
     }
+
+
+def test_discrepancy_before_audit_launch(
+    client: FlaskClient,
+    election_id: str,
+    jurisdiction_ids: List[str],  # pylint: disable=unused-argument
+):
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    assert rv.status_code == 409
+    assert json.loads(rv.data) == {
+        "errors": [
+            {
+                "errorType": "Conflict",
+                "message": "Audit not started",
+            }
+        ]
+    }
+
+
+def test_discrepancy_non_batch_comparison_enabled(
+    client: FlaskClient,
+    election_id: str,
+    jurisdiction_ids: List[str],  # pylint: disable=unused-argument
+    round_1_id: str,  # pylint: disable=unused-argument
+):
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    assert rv.status_code == 409
+    assert json.loads(rv.data) == {
+        "errors": [
+            {
+                "errorType": "Conflict",
+                "message": "Discrepancies are only implemented for batch comparison audits",
+            }
+        ]
+    }

server/tests/batch_comparison/test_batch_comparison.py

@@ -328,6 +328,28 @@ def test_batch_comparison_round_2(
     # In J2, single sampled batch hasn't been audited yet. The frontend won't show this to the user.
     assert discrepancy_counts[jurisdictions[1]["id"]] == 1
 
+    # Check discrepancies
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    discrepancies = json.loads(rv.data)
+    assert (
+        discrepancies[jurisdictions[0]["id"]]["Batch 1"][contests[0]["id"]][
+            "reportedVotes"
+        ][choice_ids[0]]
+        == 500
+    )
+    assert (
+        discrepancies[jurisdictions[0]["id"]]["Batch 1"][contests[0]["id"]][
+            "auditedVotes"
+        ][choice_ids[0]]
+        == 400
+    )
+    assert (
+        discrepancies[jurisdictions[0]["id"]]["Batch 1"][contests[0]["id"]][
+            "discrepancies"
+        ][choice_ids[0]]
+        == 100
+    )
+
     # Now do the second jurisdiction
     set_logged_in_user(
         client, UserType.JURISDICTION_ADMIN, default_ja_email(election_id)
@@ -652,10 +674,15 @@ def test_batch_comparison_batches_sampled_multiple_times(
     # Check discrepancy counts
     rv = client.get(f"/api/election/{election_id}/discrepancy-counts")
     discrepancy_counts = json.loads(rv.data)
-    print(discrepancy_counts)
     assert discrepancy_counts[jurisdictions[0]["id"]] == 0
     assert discrepancy_counts[jurisdictions[1]["id"]] == 0
 
+    # Check discrepancies
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    discrepancies = json.loads(rv.data)
+    assert jurisdictions[0]["id"] not in discrepancies
+    assert jurisdictions[1]["id"] not in discrepancies
+
     # End the round
     rv = client.post(f"/api/election/{election_id}/round/current/finish")
     assert_ok(rv)

server/tests/batch_comparison/test_multi_contest_batch_comparison.py

@@ -692,6 +692,28 @@ def test_multi_contest_batch_comparison_end_to_end(
     assert discrepancy_counts[jurisdictions[1]["id"]] == 0
     assert discrepancy_counts[jurisdictions[2]["id"]] == 1
 
+    # Check discrepancies
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    discrepancies = json.loads(rv.data)
+    assert (
+        discrepancies[jurisdictions[0]["id"]]["Batch 6"][contest_ids[0]][
+            "reportedVotes"
+        ][contest_1_choice_ids[0]]
+        == 50
+    )
+    assert (
+        discrepancies[jurisdictions[0]["id"]]["Batch 6"][contest_ids[0]][
+            "auditedVotes"
+        ][contest_1_choice_ids[0]]
+        == 49
+    )
+    assert (
+        discrepancies[jurisdictions[0]["id"]]["Batch 6"][contest_ids[0]][
+            "discrepancies"
+        ][contest_1_choice_ids[0]]
+        == 1
+    )
+
     #
     # Finish audit
     #
@@ -880,6 +902,31 @@ def test_multi_contest_batch_comparison_round_2(
     assert discrepancy_counts[jurisdiction_ids[1]] == 0
     assert discrepancy_counts[jurisdiction_ids[2]] == 0
 
+    # Check discrepancies
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    discrepancies = json.loads(rv.data)
+
+    assert (
+        discrepancies[jurisdiction_ids[0]]["Batch 7"][contest_ids[0]]["reportedVotes"][
+            contest_1_choice_ids[0]
+        ]
+        == 50
+    )
+    assert (
+        discrepancies[jurisdiction_ids[0]]["Batch 7"][contest_ids[0]]["auditedVotes"][
+            contest_1_choice_ids[0]
+        ]
+        == 0
+    )
+    assert (
+        discrepancies[jurisdiction_ids[0]]["Batch 7"][contest_ids[0]]["discrepancies"][
+            contest_1_choice_ids[0]
+        ]
+        == 50
+    )
+    assert jurisdiction_ids[1] not in discrepancies
+    assert jurisdiction_ids[2] not in discrepancies
+
     #
     # End round 1
     #
@@ -1012,6 +1059,14 @@ def test_multi_contest_batch_comparison_round_2(
     assert discrepancy_counts[jurisdiction_ids[1]] == 0
     assert discrepancy_counts[jurisdiction_ids[2]] == 0
 
+    # Check discrepancies
+    rv = client.get(f"/api/election/{election_id}/discrepancy")
+    discrepancies = json.loads(rv.data)
+
+    assert jurisdiction_ids[0] not in discrepancies
+    assert jurisdiction_ids[1] not in discrepancies
+    assert jurisdiction_ids[2] not in discrepancies
+
     #
     # End round 2 / finish audit
     #