From 8333ed887646a0cef3bdccb2e77e727ae754c775 Mon Sep 17 00:00:00 2001
From: Brett Smith <brettcsmith@brettcsmith.org>
Date: Mon, 15 Jun 2020 11:20:30 -0400
Subject: [PATCH] reports: Add RelatedPostings.group_by_account() classmethod.

---
 conservancy_beancount/reports/core.py  |  6 ++++++
 tests/test_reports_related_postings.py | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/conservancy_beancount/reports/core.py b/conservancy_beancount/reports/core.py
index d2cc864..48ba9c4 100644
--- a/conservancy_beancount/reports/core.py
+++ b/conservancy_beancount/reports/core.py
@@ -274,6 +274,12 @@ class RelatedPostings(Sequence[data.Posting]):
         for value, posts in mapping.items():
             yield value, cls(posts, _can_own=True)
 
+    @classmethod
+    def group_by_account(cls: Type[RelatedType],
+                         postings: Iterable[data.Posting],
+    ) -> Iterator[Tuple[data.Account, RelatedType]]:
+        return cls._group_by(postings, operator.attrgetter('account'))
+
     @classmethod
     def group_by_meta(cls: Type[RelatedType],
                       postings: Iterable[data.Posting],
diff --git a/tests/test_reports_related_postings.py b/tests/test_reports_related_postings.py
index 49f0534..bb4cdad 100644
--- a/tests/test_reports_related_postings.py
+++ b/tests/test_reports_related_postings.py
@@ -398,3 +398,21 @@ def test_group_by_first_meta_link(link_swap_posts):
         actual = actual_all.get(key, '')
         assert len(actual) == 2
         assert all(post.account == expect_account for post in actual)
+
+def test_group_by_account():
+    entries = [
+        testutil.Transaction(postings=[
+            ('Income:Donations', -10),
+            ('Assets:Cash', 10),
+        ]),
+        testutil.Transaction(postings=[
+            ('Income:Donations', -20),
+            ('Assets:Cash', 20),
+        ]),
+    ]
+    postings = data.Posting.from_entries(entries)
+    actual = dict(core.RelatedPostings.group_by_account(postings))
+    assert len(actual) == 2
+    for key, related in actual.items():
+        assert len(related) == 2
+        assert all(post.account == key for post in related)