Created reproduction test

Author: Viktor Tochonov

tests/FSharp.Data.GraphQL.Tests/MiddlewareTests.fs

@@ -1075,3 +1075,53 @@ let ``Object list filter: Must return empty filter when no discriminated union t
     let query = parse """query testQuery() { Properties { __typename } }"""
     let result = execute query
     ensureDirect result <| fun _ errors -> empty errors
+
+[<Fact>]
+let ``Object list filter: Must parse filter value through variable`` () =
+    // TODO: fix parsing in SchemaDefinitions.fs : line 94
+    let query =
+        parse
+            """query testQuery($filter: String) {
+                A (id : 1) {
+                    id
+                    value
+                    subjects (filter : {value_starts_with : $filter}) { ...Value }
+                }
+        }
+
+        fragment Value on Subject {
+                ...on A {
+                    id
+                    value
+                }
+                ...on B {
+                    id
+                    value
+                }
+        }"""
+    let expected =
+        NameValueLookup.ofList [
+            "A",
+            upcast
+                NameValueLookup.ofList [
+                    "id", upcast 1
+                    "value", upcast "A1"
+                    "subjects",
+                    upcast
+                        [
+                            NameValueLookup.ofList [ "id", upcast 2; "value", upcast "A2" ]
+                            NameValueLookup.ofList [ "id", upcast 6; "value", upcast "3000" ]
+                        ]
+                ]
+        ]
+    do
+        let filterValue = "3" |> JsonDocument.Parse |> _.RootElement
+        let variables = ImmutableDictionary<string, JsonElement>.Empty.Add ("filter", filterValue)
+        let filter = (StartsWith { FieldName = "value"; Value = "3" })
+        let expectedFilter : KeyValuePair<obj list, _> = kvp ([ "A"; "subjects" ]) (filter)
+        let result = executeAndVerifyFilter (query, variables, filter)
+
+        ensureDirect result <| fun data errors ->
+            empty errors
+            data |> equals (upcast expected)
+        result.Metadata.TryFind<ObjectListFilters> ("filters") |> wantValueSome |> seqEquals [ expectedFilter ]