Fix issue when an empty ArraySegment is a member of a class (#2511)

* Fix issue when an empty ArraySegmnet is a member of a class.

With latest, it crashes when trying to access the array members.

* Fix PR comments.

* Fix Qodana complaints

* Update releases.md

* Address review comments

---------

Co-authored-by: Shahar Prish <shaharp@microsoft.com>

Src/FluentAssertions/Equivalency/Steps/EnumerableEquivalencyStep.cs

@@ -61,10 +61,17 @@ internal static object[] ToArray(object value)
         {
             return ((IEnumerable)value).Cast<object>().ToArray();
         }
-        catch (InvalidOperationException) when (value.GetType().Name.Equals("ImmutableArray`1", StringComparison.Ordinal))
+        catch (InvalidOperationException) when (IsIgnorableArrayLikeType(value))
         {
-            // This is probably a default ImmutableArray<T>
+            // This is probably a default ImmutableArray<T> or an empty ArraySegment.
             return Array.Empty<object>();
         }
     }
+
+    private static bool IsIgnorableArrayLikeType(object value)
+    {
+        var type = value.GetType();
+        return type.Name.Equals("ImmutableArray`1", StringComparison.Ordinal) ||
+            (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(ArraySegment<>));
+    }
 }

Tests/FluentAssertions.Equivalency.Specs/BasicSpecs.cs

@@ -645,4 +645,20 @@ public void When_the_graph_contains_guids_it_should_properly_format_them()
         // Assert
         act.Should().Throw<XunitException>().WithMessage("Expected property actual[0].Id*to be *-*, but found *-*");
     }
+
+    [Fact]
+    public void Empty_array_segments_can_be_compared_for_equivalency()
+    {
+        // Arrange
+        var actual = new ClassWithArraySegment();
+        var expected = new ClassWithArraySegment();
+
+        // Act / Assert
+        actual.Should().BeEquivalentTo(expected);
+    }
+
+    private class ClassWithArraySegment
+    {
+        public ArraySegment<byte> Segment { get; set; }
+    }
 }

docs/_pages/releases.md

@@ -33,7 +33,7 @@ sidebar:
 * Improved the failure message for `[Not]HaveExplicitProperty` when wrapped in an `AssertionScope` and not implementing the interface - [#2403](https://github.com/fluentassertions/fluentassertions/pull/2403)
 * Improved the failure message for `[Not]HaveExplicitMethod` when wrapped in an `AssertionScope` and not implementing the interface - [#2403](https://github.com/fluentassertions/fluentassertions/pull/2403)
 * Changed `BeEquivalentTo` to exclude `private protected` members from the comparison - [#2417](https://github.com/fluentassertions/fluentassertions/pull/2417)
-
+* Fixed using `BeEquivalentTo` on an empty `ArraySegment` - [#2445](https://github.com/fluentassertions/fluentassertions/pull/2445), [#2511](https://github.com/fluentassertions/fluentassertions/pull/2511)
 
 ### Breaking Changes (for users)
 * Moved support for `DataSet`, `DataTable`, `DataRow` and `DataColumn` into a new package `FluentAssertions.DataSet` - [#2267](https://github.com/fluentassertions/fluentassertions/pull/2267)

qodana.yaml

@@ -14,6 +14,7 @@ exclude:
   - name: ConvertIfStatementToConditionalTernaryExpression
   - name: InvertIf
   - name: SimilarAnonymousTypeNearby
+  - name: UnusedMember.Local
     paths:
       - Tests
   - name: All