最近,我需要构建一个表达式树,所以我编写了以下测试方法...
/// <summary>
///
/// </summary>
[TestMethod()]
[DeploymentItem("WATrust.Shared.Infrastructure.dll")]
public void BuildForeignKeysContainsPredicate_shoud_build_contains_predicate()
{
RemoteEntityRefLoader_Accessor<ReferencedEntity> target = CreateRemoteEntityRefLoader_Accessor();
List<object> foreignKeys = new List<object>() { 1, 2, 3, 4 };
Expression<Func<ReferencedEntity, bool>> expected = (ReferencedEntity referencedEntity) => foreignKeys.Contains(referencedEntity.Id);
Expression<Func<ReferencedEntity, bool>> actual;
actual = target.BuildForeignKeysContainsPredicate(foreignKeys, "Id");
Assert.AreEqual(expected.ToString(), actual.ToString());
}
当我最终让"BuildForeignKeysContainsPredicate"方法工作起来后,我从未能够使测试通过... 这是该方法:
/// <summary>
///
/// </summary>
/// <param name="foreignKeys"></param>
/// <returns></returns>
private Expression<Func<TReferencedEntity, bool>> BuildForeignKeysContainsPredicate(List<object> foreignKeys, string primaryKey)
{
Expression<Func<TReferencedEntity, bool>> result = default(Expression<Func<TReferencedEntity, bool>>);
try
{
ParameterExpression entityParameter = Expression.Parameter(typeof(TReferencedEntity), "referencedEntity");
ConstantExpression foreignKeysParameter = Expression.Constant(foreignKeys, typeof(List<object>));
MemberExpression memberExpression = Expression.Property(entityParameter, primaryKey);
Expression convertExpression = Expression.Convert(memberExpression, typeof(object));
MethodCallExpression containsExpression = Expression.Call(foreignKeysParameter
, "Contains", new Type[] { }, convertExpression);
result = Expression.Lambda<Func<TReferencedEntity, bool>>(containsExpression, entityParameter);
}
catch (Exception ex)
{
throw ex;
}
return result;
}
但测试每次都失败,我将代码 Assert.AreEqual(expected, actual);
替换为了 Assert.AreEqual(expected.ToString(), actual.ToString());
。我明白它为什么会失败,因为当你查看 ToString 方法的结果时,它们是不同的。
Assert.AreEqual failed.
Expected:<referencedEntity => value(Shared.Infrastructure.Test.RemoteEntityRefLoaderTest+<>c__DisplayClass13).foreignKeys.Contains(Convert(referencedEntity.Id))>.
Actual :<referencedEntity => value(System.Collections.Generic.List`1[System.Object] ) .Contains(Convert(referencedEntity.Id))>.
我就是不明白为什么...有没有任何人对单元测试表达式有一般的建议,并且能给出如何使我的具体测试通过的建议?
谢谢...