Add utc now function to support utc datetime evaluation in expressions.

ExpressionEvaluator/ExpressionKeywords.cs

@@ -51,6 +51,7 @@ static ExpressionKeywords()
                 new NaturalLog(60),
                 new Sign(60),
                 new Now(60),
+                new UtcNow(60),
                 new Days(60),
                 new Hours(60),
                 new Minutes(60),

ExpressionEvaluator/Procedures/Functions/UtcNow.cs

@@ -0,0 +1,15 @@
+using System;
+using Vanderbilt.Biostatistics.Wfccm2;
+
+namespace ExpressionEvaluator.Procedures.Functions
+{
+    internal class UtcNow : Function
+    {
+        public UtcNow(int precedance)
+            : base("utcnow", precedance, 0, false)
+        {
+            _name2 = "UtcNow";
+            Datetime = () => DateTime.UtcNow;
+        }
+    }
+}

ExpressionEvaluatorTests/UtcNowFunctionTests.cs

@@ -0,0 +1,160 @@
+// ReSharper disable InconsistentNaming
+
+using System;
+using NUnit.Framework;
+using Vanderbilt.Biostatistics.Wfccm2;
+
+namespace ExpressionEvaluatorTests
+{
+    [TestFixture]
+    public class UtcNowFunctionTests
+    {
+        private Expression func;
+
+        [SetUp]
+        public void init() { func = new Expression(""); }
+
+        [TearDown]
+        public void clear() { func.Clear(); }
+
+        [Test]
+        public void UtcNow_AllLower_NoException()
+        {
+            func.Function = "utcnow()";
+        }
+
+        [Test]
+        public void UtcNow_HasCaps_NoException()
+        {
+            func.Function = "UtcNow()";
+        }
+
+        [Test]
+        public void UtcNow_AllUpper_NoException()
+        {
+            func.Function = "UTCNOW()";
+        }
+
+        [Test]
+        public void UtcNow_Evaluate_ReturnsDateTime()
+        {
+            func.Function = "utcnow()";
+            var result = func.Evaluate<DateTime>();
+            Assert.IsInstanceOf<DateTime>(result);
+        }
+
+        [Test]
+        public void UtcNow_Evaluate_ReturnsUtcKind()
+        {
+            func.Function = "utcnow()";
+            var result = func.Evaluate<DateTime>();
+            Assert.AreEqual(DateTimeKind.Utc, result.Kind);
+        }
+
+        [Test]
+        public void UtcNow_Evaluate_ReturnsCurrentUtcTime()
+        {
+            func.Function = "utcnow()";
+            var before = DateTime.UtcNow;
+            var result = func.Evaluate<DateTime>();
+            var after = DateTime.UtcNow;
+
+            Assert.GreaterOrEqual(result, before);
+            Assert.LessOrEqual(result, after);
+        }
+
+        [Test]
+        public void UtcNow_AddDays_IsCorrect()
+        {
+            func.Function = "utcnow() + days(1)";
+            var before = DateTime.UtcNow;
+            var result = func.Evaluate<DateTime>();
+            var after = DateTime.UtcNow;
+
+            Assert.GreaterOrEqual(result, before.AddDays(1));
+            Assert.LessOrEqual(result, after.AddDays(1));
+        }
+
+        [Test]
+        public void UtcNow_SubtractDays_IsCorrect()
+        {
+            func.Function = "utcnow() - days(1)";
+            var before = DateTime.UtcNow;
+            var result = func.Evaluate<DateTime>();
+            var after = DateTime.UtcNow;
+
+            Assert.GreaterOrEqual(result, before.AddDays(-1));
+            Assert.LessOrEqual(result, after.AddDays(-1));
+        }
+
+        [Test]
+        public void UtcNow_GreaterThanPastDate_IsTrue()
+        {
+            func.Function = "utcnow() > a";
+            func.AddSetVariable("a", new DateTime(2000, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.IsTrue(func.EvaluateBoolean());
+        }
+
+        [Test]
+        public void UtcNow_LessThanFutureDate_IsTrue()
+        {
+            func.Function = "utcnow() < a";
+            func.AddSetVariable("a", new DateTime(2100, 1, 1, 0, 0, 0, DateTimeKind.Utc));
+            Assert.IsTrue(func.EvaluateBoolean());
+        }
+
+        [Test]
+        public void UtcNow_GreaterOrEqualPastDate_IsTrue()
+        {
+            var testDate = DateTime.UtcNow.AddDays(-1);
+            func.Function = "utcnow() >= a";
+            func.AddSetVariable("a", testDate);
+            Assert.IsTrue(func.EvaluateBoolean());
+        }
+
+        [Test]
+        public void UtcNow_LessOrEqualFutureDate_IsTrue()
+        {
+            var testDate = DateTime.UtcNow.AddDays(1);
+            func.Function = "utcnow() <= a";
+            func.AddSetVariable("a", testDate);
+            Assert.IsTrue(func.EvaluateBoolean());
+        }
+
+        [Test]
+        public void UtcNow_SubtractVariable_ReturnsTimeSpan()
+        {
+            var pastDate = DateTime.UtcNow.AddDays(-1);
+            func.Function = "totaldays(utcnow() - a)";
+            func.AddSetVariable("a", pastDate);
+            var result = func.EvaluateNumeric();
+
+            Assert.GreaterOrEqual(result, 0.99);
+            Assert.LessOrEqual(result, 1.01);
+        }
+
+        [Test]
+        public void UtcNow_AddHours_IsCorrect()
+        {
+            func.Function = "utcnow() + hours(2)";
+            var before = DateTime.UtcNow;
+            var result = func.Evaluate<DateTime>();
+            var after = DateTime.UtcNow;
+
+            Assert.GreaterOrEqual(result, before.AddHours(2));
+            Assert.LessOrEqual(result, after.AddHours(2));
+        }
+
+        [Test]
+        public void UtcNow_AddMinutes_IsCorrect()
+        {
+            func.Function = "utcnow() + minutes(30)";
+            var before = DateTime.UtcNow;
+            var result = func.Evaluate<DateTime>();
+            var after = DateTime.UtcNow;
+
+            Assert.GreaterOrEqual(result, before.AddMinutes(30));
+            Assert.LessOrEqual(result, after.AddMinutes(30));
+        }
+    }
+}