Support casts in LINQ provider

Update `WiqlTranslator` to support casts in LINQ queries. Added unit tests for that and the `as` operator to validate changes.
LeCantaloop · May 24, 2018 · 1815ed7 · 1815ed7
1 parent f72dde5
commit 1815ed7
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diff --git a/src/Qwiq.Linq/WiqlTranslator.cs b/src/Qwiq.Linq/WiqlTranslator.cs
@@ -258,6 +258,8 @@ protected override Expression VisitUnary(UnaryExpression node)
                         _expressionInProgress.Enqueue(new StringFragment(" NOT "));
                         Visit(node.Operand);
                         break;
+                    case ExpressionType.Convert:
+                    case ExpressionType.ConvertChecked:
                     case ExpressionType.TypeAs:
                         // Casting a type; do nothing because WIQL handles type conversion
                         Visit(node.Operand);

diff --git a/test/Qwiq.Linq.Tests/QueryBuilderTests.cs b/test/Qwiq.Linq.Tests/QueryBuilderTests.cs
@@ -10,6 +10,60 @@
 
 namespace Qwiq.Linq
 {
+    [TestClass]
+    // ReSharper disable once InconsistentNaming
+    public class when_a_query_has_a_cast_in_it : WiqlQueryBuilderContextSpecification
+    {
+        private DateTime _date;
+
+        public override void Given()
+        {
+            base.Given();
+            _date = DateTime.SpecifyKind(new DateTime(2012, 11, 29, 17, 0, 0), DateTimeKind.Utc);
+        }
+
+        public override void When()
+        {
+            base.When();
+            Expected =
+                "SELECT * FROM WorkItems WHERE (([Changed Date] > '2012-11-29 17:00:00Z'))";
+            Actual = Query.Where(item => (DateTime)item["Changed Date"] > _date).ToString();
+        }
+
+        [TestMethod]
+        public void it_is_translated_to_a_where()
+        {
+            Actual.ShouldEqual(Expected);
+        }
+    }
+
+    [TestClass]
+    // ReSharper disable once InconsistentNaming
+    public class when_a_query_has_an_as_operator_in_it : WiqlQueryBuilderContextSpecification
+    {
+        private DateTime _date;
+
+        public override void Given()
+        {
+            base.Given();
+            _date = DateTime.SpecifyKind(new DateTime(2012, 11, 29, 17, 0, 0), DateTimeKind.Utc);
+        }
+
+        public override void When()
+        {
+            base.When();
+            Expected =
+                "SELECT * FROM WorkItems WHERE (([Changed Date] > '2012-11-29 17:00:00Z'))";
+            Actual = Query.Where(item => (item["Changed Date"] as DateTime?) > _date).ToString();
+        }
+
+        [TestMethod]
+        public void it_is_translated_to_a_where()
+        {
+            Actual.ShouldEqual(Expected);
+        }
+    }
+
     [TestClass]
     // ReSharper disable once InconsistentNaming
     public class when_a_query_has_a_where_clause_with_an_and_expression : WiqlQueryBuilderContextSpecification