From 655d9a5c9a19d5bc4bac66263cf7b4908404b29b Mon Sep 17 00:00:00 2001
From: IG <aloneguid@outlook.com>
Date: Thu, 30 May 2024 15:23:28 +0100
Subject: [PATCH] check that interface serialization/deserialization works
 (#513)

---
 .../Serialisation/ParquetSerializerTest.cs    | 25 +++++++++++++++++++
 .../Serialisation/SchemaReflectorTest.cs      | 16 ++++++++++++
 2 files changed, 41 insertions(+)

diff --git a/src/Parquet.Test/Serialisation/ParquetSerializerTest.cs b/src/Parquet.Test/Serialisation/ParquetSerializerTest.cs
index 725dd1a2..5b06ac04 100644
--- a/src/Parquet.Test/Serialisation/ParquetSerializerTest.cs
+++ b/src/Parquet.Test/Serialisation/ParquetSerializerTest.cs
@@ -826,6 +826,31 @@ public async Task List_Struct_WithAlias_Serde() {
             await Compare(data);
         }
 
+        interface IInterface {
+            int Id { get; set; }
+        }
+
+        class InterfaceImpl : IInterface {
+            public int Id { get; set; }
+        }
+
+        [Fact]
+        public async Task Interface_Serialize() {
+            var data = new IInterface[] {
+                new InterfaceImpl { Id = 1 },
+                new InterfaceImpl { Id = 2 },
+            };
+
+            using var ms = new MemoryStream();
+            await ParquetSerializer.SerializeAsync(data, ms);
+
+            ms.Position = 0;
+            IList<InterfaceImpl> data2 = await ParquetSerializer.DeserializeAllAsync<InterfaceImpl>(ms).ToArrayAsync();
+
+            Assert.Equivalent(data, data2);
+
+        }
+
 #if NET6_0_OR_GREATER
 
         record RecordContainingDateAndtimeOnly {
diff --git a/src/Parquet.Test/Serialisation/SchemaReflectorTest.cs b/src/Parquet.Test/Serialisation/SchemaReflectorTest.cs
index 97172fd4..6ac2c558 100644
--- a/src/Parquet.Test/Serialisation/SchemaReflectorTest.cs
+++ b/src/Parquet.Test/Serialisation/SchemaReflectorTest.cs
@@ -537,5 +537,21 @@ public void Strings_OptionalAndRequired() {
             Assert.True(s.DataFields[1].IsNullable);
             Assert.True(s.DataFields[2].IsNullable);
         }
+
+        public interface IInterface {
+            int Id { get; set; }
+        }
+
+        [Fact]
+        public void InterfaceIsSupported() {
+            ParquetSchema s = typeof(IInterface).GetParquetSchema(true);
+
+            Assert.NotNull(s);
+            DataField df = s.FindDataField(nameof(IInterface.Id));
+            Assert.True(df.GetType() == typeof(DataField));
+            Assert.Equal(SchemaType.Data, df.SchemaType);
+            Assert.Equal(typeof(int), df.ClrType);
+            Assert.False(df.IsNullable);
+        }
     }
 }
\ No newline at end of file