From 2d392c7daf0f90600a49e85b5d9d574d2038c304 Mon Sep 17 00:00:00 2001
From: Maximilian Chaplin <chaplin_max@hotmail.com>
Date: Wed, 16 Sep 2020 01:24:22 +0200
Subject: [PATCH] Assert.IsTrue() & False() to handle nullable bools (#690)

* Added `Assert.IsTrue` and `Assert.IsFalse` for nullable booleans.

Co-authored-by: Maximilian Chaplin <MXCH@simcorp.com>
---
 .../MSTest.Core/Assertions/Assert.cs          | 118 ++++++++++++++++++
 .../Assertions/AssertTests.cs                 |  22 ++++
 2 files changed, 140 insertions(+)

diff --git a/src/TestFramework/MSTest.Core/Assertions/Assert.cs b/src/TestFramework/MSTest.Core/Assertions/Assert.cs
index 9665b9f0df..68f8b5d398 100644
--- a/src/TestFramework/MSTest.Core/Assertions/Assert.cs
+++ b/src/TestFramework/MSTest.Core/Assertions/Assert.cs
@@ -65,6 +65,21 @@ public static void IsTrue(bool condition)
             IsTrue(condition, string.Empty, null);
         }
 
+        /// <summary>
+        /// Tests whether the specified condition is true and throws an exception
+        /// if the condition is false.
+        /// </summary>
+        /// <param name="condition">
+        /// The condition the test expects to be true.
+        /// </param>
+        /// <exception cref="AssertFailedException">
+        /// Thrown if <paramref name="condition"/> is false.
+        /// </exception>
+        public static void IsTrue(bool? condition)
+        {
+            IsTrue(condition, string.Empty, null);
+        }
+
         /// <summary>
         /// Tests whether the specified condition is true and throws an exception
         /// if the condition is false.
@@ -84,6 +99,25 @@ public static void IsTrue(bool condition, string message)
             IsTrue(condition, message, null);
         }
 
+        /// <summary>
+        /// Tests whether the specified condition is true and throws an exception
+        /// if the condition is false.
+        /// </summary>
+        /// <param name="condition">
+        /// The condition the test expects to be true.
+        /// </param>
+        /// <param name="message">
+        /// The message to include in the exception when <paramref name="condition"/>
+        /// is false. The message is shown in test results.
+        /// </param>
+        /// <exception cref="AssertFailedException">
+        /// Thrown if <paramref name="condition"/> is false.
+        /// </exception>
+        public static void IsTrue(bool? condition, string message)
+        {
+            IsTrue(condition, message, null);
+        }
+
         /// <summary>
         /// Tests whether the specified condition is true and throws an exception
         /// if the condition is false.
@@ -109,6 +143,31 @@ public static void IsTrue(bool condition, string message, params object[] parame
             }
         }
 
+        /// <summary>
+        /// Tests whether the specified condition is true and throws an exception
+        /// if the condition is false.
+        /// </summary>
+        /// <param name="condition">
+        /// The condition the test expects to be true.
+        /// </param>
+        /// <param name="message">
+        /// The message to include in the exception when <paramref name="condition"/>
+        /// is false. The message is shown in test results.
+        /// </param>
+        /// <param name="parameters">
+        /// An array of parameters to use when formatting <paramref name="message"/>.
+        /// </param>
+        /// <exception cref="AssertFailedException">
+        /// Thrown if <paramref name="condition"/> is false.
+        /// </exception>
+        public static void IsTrue(bool? condition, string message, params object[] parameters)
+        {
+            if (condition == false || condition == null)
+            {
+                HandleFail("Assert.IsTrue", message, parameters);
+            }
+        }
+
         /// <summary>
         /// Tests whether the specified condition is false and throws an exception
         /// if the condition is true.
@@ -124,6 +183,21 @@ public static void IsFalse(bool condition)
             IsFalse(condition, string.Empty, null);
         }
 
+        /// <summary>
+        /// Tests whether the specified condition is false and throws an exception
+        /// if the condition is true.
+        /// </summary>
+        /// <param name="condition">
+        /// The condition the test expects to be false.
+        /// </param>
+        /// <exception cref="AssertFailedException">
+        /// Thrown if <paramref name="condition"/> is true.
+        /// </exception>
+        public static void IsFalse(bool? condition)
+        {
+            IsFalse(condition, string.Empty, null);
+        }
+
         /// <summary>
         /// Tests whether the specified condition is false and throws an exception
         /// if the condition is true.
@@ -143,6 +217,25 @@ public static void IsFalse(bool condition, string message)
             IsFalse(condition, message, null);
         }
 
+        /// <summary>
+        /// Tests whether the specified condition is false and throws an exception
+        /// if the condition is true.
+        /// </summary>
+        /// <param name="condition">
+        /// The condition the test expects to be false.
+        /// </param>
+        /// <param name="message">
+        /// The message to include in the exception when <paramref name="condition"/>
+        /// is true. The message is shown in test results.
+        /// </param>
+        /// <exception cref="AssertFailedException">
+        /// Thrown if <paramref name="condition"/> is true.
+        /// </exception>
+        public static void IsFalse(bool? condition, string message)
+        {
+            IsFalse(condition, message, null);
+        }
+
         /// <summary>
         /// Tests whether the specified condition is false and throws an exception
         /// if the condition is true.
@@ -168,6 +261,31 @@ public static void IsFalse(bool condition, string message, params object[] param
             }
         }
 
+        /// <summary>
+        /// Tests whether the specified condition is false and throws an exception
+        /// if the condition is true.
+        /// </summary>
+        /// <param name="condition">
+        /// The condition the test expects to be false.
+        /// </param>
+        /// <param name="message">
+        /// The message to include in the exception when <paramref name="condition"/>
+        /// is true. The message is shown in test results.
+        /// </param>
+        /// <param name="parameters">
+        /// An array of parameters to use when formatting <paramref name="message"/>.
+        /// </param>
+        /// <exception cref="AssertFailedException">
+        /// Thrown if <paramref name="condition"/> is true.
+        /// </exception>
+        public static void IsFalse(bool? condition, string message, params object[] parameters)
+        {
+            if (condition == true || condition == null)
+            {
+                HandleFail("Assert.IsFalse", message, parameters);
+            }
+        }
+
         #endregion
 
         #region Null
diff --git a/test/UnitTests/MSTest.Core.Unit.Tests/Assertions/AssertTests.cs b/test/UnitTests/MSTest.Core.Unit.Tests/Assertions/AssertTests.cs
index dc64211915..6cabbc06ce 100644
--- a/test/UnitTests/MSTest.Core.Unit.Tests/Assertions/AssertTests.cs
+++ b/test/UnitTests/MSTest.Core.Unit.Tests/Assertions/AssertTests.cs
@@ -300,5 +300,27 @@ public void InstanceNotOfTypeShouldPassOnSubInstance()
         }
 
         #endregion
+
+        #region Nullable Booleans tests.
+
+        [TestMethod]
+        public void IsFalseNullableBooleansShouldFailWithNull()
+        {
+            bool? nullBool = null;
+            var ex = ActionUtility.PerformActionAndReturnException(() => TestFrameworkV2.Assert.IsFalse(nullBool));
+            Assert.IsNotNull(ex);
+            StringAssert.Contains(ex.Message, "Assert.IsFalse failed");
+        }
+
+        [TestMethod]
+        public void IsTrueNullableBooleansShouldFailWithNull()
+        {
+            bool? nullBool = null;
+
+            var ex = ActionUtility.PerformActionAndReturnException(() => TestFrameworkV2.Assert.IsTrue(nullBool));
+            Assert.IsNotNull(ex);
+            StringAssert.Contains(ex.Message, "Assert.IsTrue failed");
+        }
+        #endregion
     }
 }