From aa498af0c2b850d5da157bad51fccb0b35d8accb Mon Sep 17 00:00:00 2001
From: Simon Brunning <simon@brunningonline.net>
Date: Wed, 24 Feb 2021 14:23:27 +0000
Subject: [PATCH] If has_entry() has only a single matching key, report the
 matching value.

---
 .../library/collection/isdict_containing.py   | 22 ++++++++++++++-----
 .../collection/isdict_containing_test.py      | 10 ++++++---
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/src/hamcrest/library/collection/isdict_containing.py b/src/hamcrest/library/collection/isdict_containing.py
index 092ca7b4..6ddce47f 100644
--- a/src/hamcrest/library/collection/isdict_containing.py
+++ b/src/hamcrest/library/collection/isdict_containing.py
@@ -33,11 +33,7 @@ def describe_to(self, description: Description) -> None:
         ).append_text(": ").append_description_of(self.value_matcher).append_text("]")
 
     def describe_mismatch(self, item: Mapping[K, V], mismatch_description: Description) -> None:
-        key_matches: MutableMapping[K, V] = {}
-        if hasmethod(item, "items"):
-            for key, value in item.items():
-                if self.key_matcher.matches(key):
-                    key_matches[key] = value
+        key_matches = self._matching_keys(item)
         if len(key_matches) == 1:
             key, value = key_matches.popitem()
             mismatch_description.append_text("value for ").append_description_of(key).append_text(
@@ -48,7 +44,21 @@ def describe_mismatch(self, item: Mapping[K, V], mismatch_description: Descripti
             super().describe_mismatch(item, mismatch_description)
 
     def describe_match(self, item: Mapping[K, V], match_description: Description) -> None:
-        super().describe_match(item, match_description)
+        key_matches = self._matching_keys(item)
+        if len(key_matches) == 1:
+            key, value = key_matches.popitem()
+            match_description.append_text("value for ").append_description_of(key).append_text(" ")
+            self.value_matcher.describe_mismatch(value, match_description)
+        else:
+            super().describe_match(item, match_description)
+
+    def _matching_keys(self, item):
+        key_matches: MutableMapping[K, V] = {}
+        if hasmethod(item, "items"):
+            for key, value in item.items():
+                if self.key_matcher.matches(key):
+                    key_matches[key] = value
+        return key_matches
 
 
 def has_entry(
diff --git a/tests/hamcrest_unit_test/collection/isdict_containing_test.py b/tests/hamcrest_unit_test/collection/isdict_containing_test.py
index a9a92cb0..b0737876 100644
--- a/tests/hamcrest_unit_test/collection/isdict_containing_test.py
+++ b/tests/hamcrest_unit_test/collection/isdict_containing_test.py
@@ -3,7 +3,11 @@
 from hamcrest import starts_with
 from hamcrest.core.core.isequal import equal_to
 from hamcrest.library.collection.isdict_containing import has_entry
-from hamcrest_unit_test.matcher_test import MatcherTest, assert_mismatch_description
+from hamcrest_unit_test.matcher_test import (
+    MatcherTest,
+    assert_match_description,
+    assert_mismatch_description,
+)
 
 from .quasidict import QuasiDictionary
 
@@ -50,8 +54,8 @@ def test_describe_single_matching_key_mismatching_value(self):
             "was <{'ab': 2, 'ac': 3}>", has_entry(starts_with("a"), 1), {"ab": 2, "ac": 3}
         )
 
-    # def test_describe_match(self):
-    #     assert_match_description("value for 'a' was <1>", has_entry("a", 1), {"a": 1})
+    def test_describe_match(self):
+        assert_match_description("value for 'a' was <1>", has_entry("a", 1), {"a": 1, "b": 2})
 
 
 if __name__ == "__main__":