Broke ContractTest tests into more granular units

Previously, a couple of common overloads, such as passing conditions instead of objects, were not tested. This is likely because those were originally supplied by Microsoft's implementation. Now that they're supplied by Ignia's `Contract` class, they should be subjected to full test coverage. As part of this, I also adopted the more expressive test naming convention recently applied to `AttributeValueCollectionTest` (see #496f06d): `METHOD_CONDITION_RESULT` (e.g., `GetValue_IncorrectKey_ReturnsDefault()`).

Author: JeremyCaney

OnTopic.Tests/ContractTest.cs

@@ -19,46 +19,58 @@ namespace OnTopic.Tests {
   public class ContractTest {
 
     /*==========================================================================================================================
-    | TEST: REQUIRES
+    | TEST: REQUIRES: CONDITION IS TRUE: THROW NO EXCEPTION
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
-    ///   Tests a non-null argument using the <see cref="Contract"/> class, and validates that it correctly does nothing.
+    ///   Tests a true condition using the <see cref="Contract"/> class, and validates that it correctly does nothing.
     /// </summary>
     [TestMethod]
-    public void Requires() {
-
-      var argument = new Object();
+    public void Requires_ConditionIsTrue_ThrowNoException()
+      => Contract.Requires(true, "The argument cannot be null");
 
-      Contract.Requires(argument, "The argument cannot be null");
+    /*==========================================================================================================================
+    | TEST: REQUIRES: CONDITION IS FALSE: THROW ARGUMENT NULL EXCEPTION
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Tests a false condition using the <see cref="Contract"/> class, and validates that it correctly returns an <see
+    ///   cref="ArgumentNullException"/>.
+    /// </summary>
+    [TestMethod]
+    [ExpectedException(typeof(Exception))]
+    public void Requires_ConditionIsFalse_ThrowArgumentNullException()
+      => Contract.Requires(false, "The argument cannot be null");
 
-    }
+    /*==========================================================================================================================
+    | TEST: REQUIRES: OBJECT EXISTS: THROW NO EXCEPTION
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Tests a non-null argument using the <see cref="Contract"/> class, and validates that it correctly does nothing.
+    /// </summary>
+    [TestMethod]
+    public void Requires_ObjectExists_ThrowNoException() =>
+      Contract.Requires(new Object(), "The argument cannot be null");
 
     /*==========================================================================================================================
-    | TEST: REQUIRES (ARGUMENT NULL EXCEPTION)
+    | TEST: REQUIRES: OBJECT IS NULL: THROW ARGUMENT NULL EXCEPTION
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Tests a null argument using the <see cref="Contract"/> class, and validates that it correctly returns an <see
     ///   cref="ArgumentNullException"/>.
     /// </summary>
     [TestMethod]
     [ExpectedException(typeof(ArgumentNullException))]
-    public void RequiresArgumentNullException() {
-
-      var argument = (object?)null;
-
-      Contract.Requires(argument, "The argument cannot be null");
-
-    }
+    public void Requires_ObjectIsNull_ThrowArgumentNullException() =>
+      Contract.Requires(null, "The argument cannot be null");
 
     /*==========================================================================================================================
-    | TEST: REQUIRES (EXCEPTION MESSAGE)
+    | TEST: REQUIRES: MESSAGE EXISTS: THROW EXCEPTION WITH MESSAGE
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Tests a null argument using the <see cref="Contract"/> class, and validates that it correctly returns an <see
     ///   cref="ArgumentNullException"/> with the expected <see cref="ArgumentException.Message"/>.
     /// </summary>
     [TestMethod]
-    public void RequiresExceptionMessage() {
+    public void Requires_MessageExists_ThrowExceptionWithMessage() {
 
       var argument = (object?)null;
       var errorMessage = "The argument cannot be null";
@@ -73,21 +85,38 @@ public void RequiresExceptionMessage() {
     }
 
     /*==========================================================================================================================
-    | TEST: ASSUME (INVALID OPERATION EXCEPTION)
+    | TEST: ASSUME: CONDITION IS TRUE: THROW NO EXCEPTION
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Tests a true condition using the <see cref="Contract"/> class, and validates that it correctly does nothing.
+    /// </summary>
+    [TestMethod]
+    public void Assume_ConditionIsTrue_ThrowNoException()
+      => Contract.Assume(true, "The argument cannot be null");
+
+    /*==========================================================================================================================
+    | TEST: ASSUME: CONDITION IS FALSE: THROW ARGUMENT NULL EXCEPTION
+    \-------------------------------------------------------------------------------------------------------------------------*/
+    /// <summary>
+    ///   Tests a false condition using the <see cref="Contract"/> class, and validates that it correctly returns an <see
+    ///   cref="ArgumentNullException"/>.
+    /// </summary>
+    [TestMethod]
+    [ExpectedException(typeof(Exception))]
+    public void Assume_ConditionIsFalse_ThrowArgumentNullException()
+      => Contract.Assume(false, "The argument cannot be null");
+
+    /*==========================================================================================================================
+    | TEST: ASSUME: OBJECT IS NULL: THROW INVALID OPERATION EXCEPTION
     \-------------------------------------------------------------------------------------------------------------------------*/
     /// <summary>
     ///   Tests a null assignment using the <see cref="Contract"/> class, and validates that it correctly returns an <see
     ///   cref="InvalidOperationException"/>.
     /// </summary>
     [TestMethod]
     [ExpectedException(typeof(InvalidOperationException))]
-    public void AssumeInvalidOperationException() {
-
-      var variable = (object?)null;
-
-      Contract.Assume(variable, "The local runtime state is invalid.");
-
-    }
+    public void Assume_ObjectIsNull_ThrowInvalidOperationException()
+      => Contract.Assume(null, "The local runtime state is invalid.");
 
   } //Class
 } //Namespace