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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
// Conditional to use more aggressive fail-fast behaviors when debugging.
#define DEV_DEBUG
// This file contains general utilities to aid in development.
// It is distinct from unit test Assert classes.
// Classes here generally shouldn't be exposed publicly since
// they're not particular to any library functionality.
// Because the classes here are internal, it's likely this file
// might be included in multiple assemblies.
namespace Standard
{
using System;
using System.Diagnostics;
using System.Threading;
/// <summary>A static class for verifying assumptions.</summary>
internal static class Assert
{
private static void _Break()
{
#if DEV_DEBUG
Debugger.Break();
#else
Debug.Assert(false);
#endif
}
/// <summary>A function signature for Assert.Evaluate.</summary>
public delegate void EvaluateFunction();
/// <summary>A function signature for Assert.Implies.</summary>
/// <returns>Returns the truth of a predicate.</returns>
public delegate bool ImplicationFunction();
/// <summary>
/// Executes the specified argument.
/// </summary>
/// <param name="argument">The function to execute.</param>
[Conditional("DEBUG")]
public static void Evaluate(EvaluateFunction argument)
{
IsNotNull(argument);
argument();
}
/// <summary>Obsolete: Use Standard.Assert.AreEqual instead of Assert.Equals</summary>
/// <typeparam name="T">The generic type to compare for equality.</typeparam>
/// <param name="expected">The first generic type data to compare. This is is the expected value.</param>
/// <param name="actual">The second generic type data to compare. This is the actual value.</param>
[
Obsolete("Use Assert.AreEqual instead of Assert.Equals", false),
Conditional("DEBUG")
]
public static void Equals<T>(T expected, T actual)
{
AreEqual(expected, actual);
}
/// <summary>
/// Verifies that two generic type data are equal. The assertion fails if they are not.
/// </summary>
/// <typeparam name="T">The generic type to compare for equality.</typeparam>
/// <param name="expected">The first generic type data to compare. This is is the expected value.</param>
/// <param name="actual">The second generic type data to compare. This is the actual value.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void AreEqual<T>(T expected, T actual)
{
if (null == expected)
{
// Two nulls are considered equal, regardless of type semantics.
if (null != actual && !actual.Equals(expected))
{
_Break();
}
}
else if (!expected.Equals(actual))
{
_Break();
}
}
/// <summary>
/// Verifies that two generic type data are not equal. The assertion fails if they are.
/// </summary>
/// <typeparam name="T">The generic type to compare for inequality.</typeparam>
/// <param name="notExpected">The first generic type data to compare. This is is the value that's not expected.</param>
/// <param name="actual">The second generic type data to compare. This is the actual value.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void AreNotEqual<T>(T notExpected, T actual)
{
if (null == notExpected)
{
// Two nulls are considered equal, regardless of type semantics.
if (null == actual || actual.Equals(notExpected))
{
_Break();
}
}
else if (notExpected.Equals(actual))
{
_Break();
}
}
/// <summary>
/// Verifies that if the specified condition is true, then so is the result.
/// The assertion fails if the condition is true but the result is false.
/// </summary>
/// <param name="condition">if set to <c>true</c> [condition].</param>
/// <param name="result">
/// A second Boolean statement. If the first was true then so must this be.
/// If the first statement was false then the value of this is ignored.
/// </param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void Implies(bool condition, bool result)
{
if (condition && !result)
{
_Break();
}
}
/// <summary>
/// Lazy evaluation overload. Verifies that if a condition is true, then so is a secondary value.
/// </summary>
/// <param name="condition">The conditional value.</param>
/// <param name="result">A function to be evaluated for truth if the condition argument is true.</param>
/// <remarks>
/// This overload only evaluates the result if the first condition is true.
/// </remarks>
[Conditional("DEBUG")]
public static void Implies(bool condition, ImplicationFunction result)
{
if (condition && !result())
{
_Break();
}
}
/// <summary>
/// Verifies that a string has content. I.e. it is not null and it is not empty.
/// </summary>
/// <param name="value">The string to verify.</param>
[Conditional("DEBUG")]
public static void IsNeitherNullNorEmpty(string value)
{
IsFalse(string.IsNullOrEmpty(value));
}
/// <summary>
/// Verifies that a string has content. I.e. it is not null and it is not purely whitespace.
/// </summary>
/// <param name="value">The string to verify.</param>
[Conditional("DEBUG")]
public static void IsNeitherNullNorWhitespace(string value)
{
if (string.IsNullOrEmpty(value))
{
_Break();
}
if (value.Trim().Length == 0)
{
_Break();
}
}
/// <summary>
/// Verifies the specified value is not null. The assertion fails if it is.
/// </summary>
/// <typeparam name="T">The generic reference type.</typeparam>
/// <param name="value">The value to check for nullness.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void IsNotNull<T>(T value) where T : class
{
if (null == value)
{
_Break();
}
}
[Conditional("DEBUG")]
public static void IsDefault<T>(T value) where T : struct
{
if (!value.Equals(default(T)))
{
Assert.Fail();
}
}
[Conditional("DEBUG")]
public static void IsNotDefault<T>(T value) where T : struct
{
if (value.Equals(default(T)))
{
Assert.Fail();
}
}
/// <summary>
/// Verifies that the specified condition is false. The assertion fails if it is true.
/// </summary>
/// <param name="condition">The expression that should be <c>false</c>.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void IsFalse(bool condition)
{
if (condition)
{
_Break();
}
}
/// <summary>
/// Verifies that the specified condition is false. The assertion fails if it is true.
/// </summary>
/// <param name="condition">The expression that should be <c>false</c>.</param>
/// <param name="message">The message to display if the condition is <c>true</c>.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void IsFalse(bool condition, string message)
{
if (condition)
{
_Break();
}
}
/// <summary>
/// Verifies that the specified condition is true. The assertion fails if it is not.
/// </summary>
/// <param name="condition">A condition that is expected to be <c>true</c>.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void IsTrue(bool condition)
{
if (!condition)
{
_Break();
}
}
/// <summary>
/// Verifies that the specified condition is true. The assertion fails if it is not.
/// </summary>
/// <param name="condition">A condition that is expected to be <c>true</c>.</param>
/// <param name="message">The message to write in case the condition is <c>false</c>.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void IsTrue(bool condition, string message)
{
if (!condition)
{
_Break();
}
}
/// <summary>
/// This line should never be executed. The assertion always fails.
/// </summary>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void Fail()
{
_Break();
}
/// <summary>
/// This line should never be executed. The assertion always fails.
/// </summary>
/// <param name="message">The message to display if this function is executed.</param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void Fail(string message)
{
_Break();
}
/// <summary>
/// Verifies that the specified object is null. The assertion fails if it is not.
/// </summary>
/// <param name="item">The item to verify is null.</param>
[Conditional("DEBUG")]
public static void IsNull<T>(T item) where T : class
{
if (null != item)
{
_Break();
}
}
/// <summary>
/// Verifies that the specified value is within the expected range. The assertion fails if it isn't.
/// </summary>
/// <param name="lowerBoundInclusive">The lower bound inclusive value.</param>
/// <param name="value">The value to verify.</param>
/// <param name="upperBoundInclusive">The upper bound inclusive value.</param>
[Conditional("DEBUG")]
public static void BoundedDoubleInc(double lowerBoundInclusive, double value, double upperBoundInclusive)
{
if (value < lowerBoundInclusive || value > upperBoundInclusive)
{
_Break();
}
}
/// <summary>
/// Verifies that the specified value is within the expected range. The assertion fails if it isn't.
/// </summary>
/// <param name="lowerBoundInclusive">The lower bound inclusive value.</param>
/// <param name="value">The value to verify.</param>
/// <param name="upperBoundExclusive">The upper bound exclusive value.</param>
[Conditional("DEBUG")]
public static void BoundedInteger(int lowerBoundInclusive, int value, int upperBoundExclusive)
{
if (value < lowerBoundInclusive || value >= upperBoundExclusive)
{
_Break();
}
}
/// <summary>
/// Verify the current thread's apartment state is what's expected. The assertion fails if it isn't
/// </summary>
/// <param name="expectedState">
/// The expected apartment state for the current thread.
/// </param>
/// <remarks>This breaks into the debugger in the case of a failed assertion.</remarks>
[Conditional("DEBUG")]
public static void IsApartmentState(ApartmentState expectedState)
{
if (Thread.CurrentThread.GetApartmentState() != expectedState)
{
_Break();
}
}
[Conditional("DEBUG")]
public static void NullableIsNotNull<T>(T? value) where T : struct
{
if (null == value)
{
_Break();
}
}
[Conditional("DEBUG")]
public static void NullableIsNull<T>(T? value) where T : struct
{
if (null != value)
{
_Break();
}
}
[Conditional("DEBUG")]
public static void IsNotOnMainThread()
{
if (System.Windows.Application.Current.Dispatcher.CheckAccess())
{
_Break();
}
}
}
}
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