1 // ***********************************************************************
2 // Copyright (c) 2011 Charlie Poole
4 // Permission is hereby granted, free of charge, to any person obtaining
5 // a copy of this software and associated documentation files (the
6 // "Software"), to deal in the Software without restriction, including
7 // without limitation the rights to use, copy, modify, merge, publish,
8 // distribute, sublicense, and/or sell copies of the Software, and to
9 // permit persons to whom the Software is furnished to do so, subject to
10 // the following conditions:
12 // The above copyright notice and this permission notice shall be
13 // included in all copies or substantial portions of the Software.
15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
19 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
20 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
21 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 // ***********************************************************************
25 #define NUNIT_FRAMEWORK
30 using System.Collections;
32 namespace NUnit.Framework.Constraints
35 /// ExactCountConstraint applies another constraint to each
36 /// item in a collection, succeeding only if a specified
37 /// number of items succeed.
39 public class ExactCountConstraint : PrefixConstraint
41 private int expectedCount;
44 /// Construct an ExactCountConstraint on top of an existing constraint
46 /// <param name="expectedCount"></param>
47 /// <param name="itemConstraint"></param>
48 public ExactCountConstraint(int expectedCount, IConstraint itemConstraint)
49 : base(itemConstraint)
51 this.expectedCount = expectedCount;
52 this.DescriptionPrefix = expectedCount == 0
56 : string.Format("exactly {0} items", expectedCount);
60 /// Apply the item constraint to each item in the collection,
61 /// succeeding only if the expected number of items pass.
63 /// <param name="actual"></param>
64 /// <returns></returns>
65 public override ConstraintResult ApplyTo<TActual>(TActual actual)
67 if (!(actual is IEnumerable))
68 throw new ArgumentException("The actual value must be an IEnumerable", "actual");
71 foreach (object item in (IEnumerable)actual)
72 if (BaseConstraint.ApplyTo(item).IsSuccess)
75 return new ConstraintResult(this, actual, count == expectedCount);