feat(tests): add helper extension to get ef sql output

Author: jaredcnance

test/JsonApiDotNetCoreExampleTests/Helpers/Extensions/IQueryableExtensions.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Linq;
+using System.Reflection;
+using Microsoft.EntityFrameworkCore.Internal;
+using Microsoft.EntityFrameworkCore.Query;
+using Microsoft.EntityFrameworkCore.Query.Internal;
+using Remotion.Linq.Parsing.Structure;
+using Database = Microsoft.EntityFrameworkCore.Storage.Database;
+
+namespace JsonApiDotNetCoreExampleTests.Helpers.Extensions
+{
+
+    public static class IQueryableExtensions
+    {
+        private static readonly TypeInfo QueryCompilerTypeInfo = typeof(QueryCompiler).GetTypeInfo();
+
+        private static readonly FieldInfo QueryCompilerField = typeof(EntityQueryProvider).GetTypeInfo().DeclaredFields.First(x => x.Name == "_queryCompiler");
+
+        private static readonly PropertyInfo NodeTypeProviderField = QueryCompilerTypeInfo.DeclaredProperties.Single(x => x.Name == "NodeTypeProvider");
+
+        private static readonly MethodInfo CreateQueryParserMethod = QueryCompilerTypeInfo.DeclaredMethods.First(x => x.Name == "CreateQueryParser");
+
+        private static readonly FieldInfo DataBaseField = QueryCompilerTypeInfo.DeclaredFields.Single(x => x.Name == "_database");
+
+        private static readonly FieldInfo QueryCompilationContextFactoryField = typeof(Database).GetTypeInfo().DeclaredFields.Single(x => x.Name == "_queryCompilationContextFactory");
+
+        public static string ToSql<TEntity>(this IQueryable<TEntity> query) where TEntity : class
+        {
+            if (!(query is EntityQueryable<TEntity>) && !(query is InternalDbSet<TEntity>))
+                throw new ArgumentException("Invalid query");
+
+            var queryCompiler = (IQueryCompiler)QueryCompilerField.GetValue(query.Provider);
+            var nodeTypeProvider = (INodeTypeProvider)NodeTypeProviderField.GetValue(queryCompiler);
+            var parser = (IQueryParser)CreateQueryParserMethod.Invoke(queryCompiler, new object[] { nodeTypeProvider });
+            var queryModel = parser.GetParsedQuery(query.Expression);
+            var database = DataBaseField.GetValue(queryCompiler);
+            var queryCompilationContextFactory = (IQueryCompilationContextFactory)QueryCompilationContextFactoryField.GetValue(database);
+            var queryCompilationContext = queryCompilationContextFactory.Create(false);
+            var modelVisitor = (RelationalQueryModelVisitor)queryCompilationContext.CreateQueryModelVisitor();
+            modelVisitor.CreateQueryExecutor<TEntity>(queryModel);
+            var sql = modelVisitor.Queries.First().ToString();
+
+            return sql;
+        }
+    }
+}