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author | E.Z. Hart <hartez@users.noreply.github.com> | 2016-12-01 14:15:17 -0700 |
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committer | Stephane Delcroix <stephane@delcroix.org> | 2016-12-01 22:15:17 +0100 |
commit | 46c25a2edbf257153d7bb33d2ac3997a3718e3ee (patch) | |
tree | 92209a25a152c11af33684c1e1933514ac4c407a /Xamarin.Forms.Core.UnitTests | |
parent | 3d85653f270854b4aab82e45e6e58afb760feb85 (diff) | |
download | xamarin-forms-46c25a2edbf257153d7bb33d2ac3997a3718e3ee.tar.gz xamarin-forms-46c25a2edbf257153d7bb33d2ac3997a3718e3ee.tar.bz2 xamarin-forms-46c25a2edbf257153d7bb33d2ac3997a3718e3ee.zip |
Don't run Command CanExecute on incorrect inherited binding context type (#572)
* Allow Command CanExecute to recover when run on inherited bindingcontext
* Make exception handler more generic
* Checking types in Command delegates to avoid exception in the first place
* Adding type chekc to other Command constructor
* Use nameof for ArgumentNullExceptions
* Add unit tests for null parameters, handle value types and Nullable<T>
Diffstat (limited to 'Xamarin.Forms.Core.UnitTests')
-rw-r--r-- | Xamarin.Forms.Core.UnitTests/CommandTests.cs | 100 |
1 files changed, 99 insertions, 1 deletions
diff --git a/Xamarin.Forms.Core.UnitTests/CommandTests.cs b/Xamarin.Forms.Core.UnitTests/CommandTests.cs index 1182fe40..c653b976 100644 --- a/Xamarin.Forms.Core.UnitTests/CommandTests.cs +++ b/Xamarin.Forms.Core.UnitTests/CommandTests.cs @@ -1,7 +1,6 @@ using System; using NUnit.Framework; - namespace Xamarin.Forms.Core.UnitTests { [TestFixture] @@ -151,5 +150,104 @@ namespace Xamarin.Forms.Core.UnitTests Assert.AreEqual (expected, cmd.CanExecute ("Foo")); Assert.AreEqual ("Foo", result); } + + class FakeParentContext + { + } + + // ReSharper disable once ClassNeverInstantiated.Local + class FakeChildContext + { + } + + [Test] + public void CanExecuteReturnsFalseIfParameterIsWrongReferenceType() + { + var command = new Command<FakeChildContext>(context => { }, context => true); + + Assert.IsFalse(command.CanExecute(new FakeParentContext()), "the parameter is of the wrong type"); + } + + [Test] + public void CanExecuteReturnsFalseIfParameterIsWrongValueType() + { + var command = new Command<int>(context => { }, context => true); + + Assert.IsFalse(command.CanExecute(10.5), "the parameter is of the wrong type"); + } + + [Test] + public void CanExecuteUsesParameterIfReferenceTypeAndSetToNull() + { + var command = new Command<FakeChildContext>(context => { }, context => true); + + Assert.IsTrue(command.CanExecute(null), "null is a valid value for a reference type"); + } + + [Test] + public void CanExecuteUsesParameterIfNullableAndSetToNull() + { + var command = new Command<int?>(context => { }, context => true); + + Assert.IsTrue(command.CanExecute(null), "null is a valid value for a Nullable<int> type"); + } + + [Test] + public void CanExecuteIgnoresParameterIfValueTypeAndSetToNull() + { + var command = new Command<int>(context => { }, context => true); + + Assert.IsFalse(command.CanExecute(null), "null is not a valid valid for int"); + } + + [Test] + public void ExecuteDoesNotRunIfParameterIsWrongReferenceType() + { + int executions = 0; + var command = new Command<FakeChildContext>(context => executions += 1); + + Assert.DoesNotThrow(() => command.Execute(new FakeParentContext()), "the command should not execute, so no exception should be thrown"); + Assert.IsTrue(executions == 0, "the command should not have executed"); + } + + [Test] + public void ExecuteDoesNotRunIfParameterIsWrongValueType() + { + int executions = 0; + var command = new Command<int>(context => executions += 1); + + Assert.DoesNotThrow(() => command.Execute(10.5), "the command should not execute, so no exception should be thrown"); + Assert.IsTrue(executions == 0, "the command should not have executed"); + } + + [Test] + public void ExecuteRunsIfReferenceTypeAndSetToNull() + { + int executions = 0; + var command = new Command<FakeChildContext>(context => executions += 1); + + Assert.DoesNotThrow(() => command.Execute(null), "null is a valid value for a reference type"); + Assert.IsTrue(executions == 1, "the command should have executed"); + } + + [Test] + public void ExecuteRunsIfNullableAndSetToNull() + { + int executions = 0; + var command = new Command<int?>(context => executions += 1); + + Assert.DoesNotThrow(() => command.Execute(null), "null is a valid value for a Nullable<int> type"); + Assert.IsTrue(executions == 1, "the command should have executed"); + } + + [Test] + public void ExecuteDoesNotRunIfValueTypeAndSetToNull() + { + int executions = 0; + var command = new Command<int>(context => executions += 1); + + Assert.DoesNotThrow(() => command.Execute(null), "null is not a valid value for int"); + Assert.IsTrue(executions == 0, "the command should not have executed"); + } } } |