MSTest / VSTest retry (rerun) logic












0















Unfortunately, there's no native test rerun logic for MStest / VStest



I'm trying to implement a custom logic like this:



Test part:



    static int testNum = 1;

[TestMethod]
public void RerunTestOnce_Test()
{
testNum = testNum + 1;
Console.WriteLine("Test started");
Assert.IsTrue(testNum == 3, $"Test Failed with number {testNum}");

}


This test should fail for the first time, and pass for the second, when testNum reach value 3.



UP: This is a synthetic example to emulate fail at first run. Real tests are complex and have UI search methods and other work with a system and network, and there's no confidence that everything will be fine during a big & long test suite.



There is a special method for this - RerunTestOnce(), called in TestCleanup:



    [TestCleanup]
public void TestCleanup()
{
TestHelper.RerunTestOnce(TestContext, this);
}


And here is implementation of RerunTestOnce in test helper class.
In it, using Reflection & TestContext we get names of test method and initialize method, and run them again:



 public static void RerunTestOnce(TestContext testContext, object testInstance)
{
if (testContext.CurrentTestOutcome == UnitTestOutcome.Failed)
{
var type = testInstance.GetType();
if (type != null)
{
var testMethod = type.GetMethod(testContext.TestName);
var initMethod = type.GetMethods().SingleOrDefault(m=>m.CustomAttributes.SingleOrDefault(a=>a.AttributeType.Name == "TestInitializeAttribute")!= null);
var cleanupMethod = type.GetMethods().SingleOrDefault(m => m.CustomAttributes.SingleOrDefault(a => a.AttributeType.Name == "TestCleanupAttribute") != null);

Console.WriteLine($"[WARNING] Method [{testMethod}] was failed in first attempt. Trying to rerun...");
try
{
initMethod.Invoke(testInstance, null);
testMethod.Invoke(testInstance, null);
}
catch
{
Console.WriteLine($"[ERROR] Method [{testMethod}] was failed in second attempt. Rerun finished.");
}
}
}
}


Everything is ok, on the second attempt test method passes, but in the end I see Failed result and assert error message from first attempt:



Test Failed - RerunTestOnce_Test
Message: Assert.IsTrue failed. Test Failed with number 2


How and when MSTest creates test result - is it possible to update test result after second attempt to last result?










share|improve this question




















  • 1





    Why jump through all these hoops? "This should be done three times, succeeding the first time and failing the second" is part of the logic of your code, and should be expressed clearly as such in the test itself, not as a re-run of the test method. You can use something like Fluent Assertions to express this succinctly (.Should().[Not]Throw()) and wrap the whole thing as a method that takes an Action delegate if you need to reuse this logic.

    – Jeroen Mostert
    Nov 22 '18 at 12:07











  • Jeroen Mostert Test expected to be passed always. This is just synthetic example to emulate fail at first run. So, if run by some reason failed, I need to rerun whole test, and only if it failed for the second time, the result should be failed.

    – Vladimir
    Nov 22 '18 at 12:14






  • 2





    Consider fixing the code so it doesn't fail the first time. If the tests are sufficiently brittle that they're "expected to possibly fail the first time", that's not a good thing! You should use this as an opportunity to make the code reliable enough to test (by waiting on a server to become available or somesuch), not as an incentive to change the tests. If you really need this you should probably set up an external test runner/build server that can invoke the whole set of tests (with vstest.console.exe for example) that applies this "retry logic" based on whether any test failed.

    – Jeroen Mostert
    Nov 22 '18 at 12:19













  • Again, the example is synthetic. There are not a "unit tests". Real tests are complex and have UI search methods and other work with a system and network. In a big test suite there's no 100% confidence that everything will be fine during test execution. That's why some progressive test frameworks like NUnit have implemented "retry" logic. Unfortunately, NUnit is not compatable with Coded UI tests, which we use.

    – Vladimir
    Nov 22 '18 at 12:40











  • Consider just using two test projects -- MSTest for the coded UI and NUnit or whatever else you prefer for the other. Otherwise you'll probably keep trying to stick a square peg in a round hole. You may need a bit of plumbing to get both test projects to run for one solution, but that still sounds simpler than trying to change MSTest at its core. If you're stuck with MSTest (for whatever reason), one option might be T4 templates to auto-generate scaffolding for the test classes so they can be retried without having to write code for it. You can log the extra attempts in the test context.

    – Jeroen Mostert
    Nov 22 '18 at 12:50
















0















Unfortunately, there's no native test rerun logic for MStest / VStest



I'm trying to implement a custom logic like this:



Test part:



    static int testNum = 1;

[TestMethod]
public void RerunTestOnce_Test()
{
testNum = testNum + 1;
Console.WriteLine("Test started");
Assert.IsTrue(testNum == 3, $"Test Failed with number {testNum}");

}


This test should fail for the first time, and pass for the second, when testNum reach value 3.



UP: This is a synthetic example to emulate fail at first run. Real tests are complex and have UI search methods and other work with a system and network, and there's no confidence that everything will be fine during a big & long test suite.



There is a special method for this - RerunTestOnce(), called in TestCleanup:



    [TestCleanup]
public void TestCleanup()
{
TestHelper.RerunTestOnce(TestContext, this);
}


And here is implementation of RerunTestOnce in test helper class.
In it, using Reflection & TestContext we get names of test method and initialize method, and run them again:



 public static void RerunTestOnce(TestContext testContext, object testInstance)
{
if (testContext.CurrentTestOutcome == UnitTestOutcome.Failed)
{
var type = testInstance.GetType();
if (type != null)
{
var testMethod = type.GetMethod(testContext.TestName);
var initMethod = type.GetMethods().SingleOrDefault(m=>m.CustomAttributes.SingleOrDefault(a=>a.AttributeType.Name == "TestInitializeAttribute")!= null);
var cleanupMethod = type.GetMethods().SingleOrDefault(m => m.CustomAttributes.SingleOrDefault(a => a.AttributeType.Name == "TestCleanupAttribute") != null);

Console.WriteLine($"[WARNING] Method [{testMethod}] was failed in first attempt. Trying to rerun...");
try
{
initMethod.Invoke(testInstance, null);
testMethod.Invoke(testInstance, null);
}
catch
{
Console.WriteLine($"[ERROR] Method [{testMethod}] was failed in second attempt. Rerun finished.");
}
}
}
}


Everything is ok, on the second attempt test method passes, but in the end I see Failed result and assert error message from first attempt:



Test Failed - RerunTestOnce_Test
Message: Assert.IsTrue failed. Test Failed with number 2


How and when MSTest creates test result - is it possible to update test result after second attempt to last result?










share|improve this question




















  • 1





    Why jump through all these hoops? "This should be done three times, succeeding the first time and failing the second" is part of the logic of your code, and should be expressed clearly as such in the test itself, not as a re-run of the test method. You can use something like Fluent Assertions to express this succinctly (.Should().[Not]Throw()) and wrap the whole thing as a method that takes an Action delegate if you need to reuse this logic.

    – Jeroen Mostert
    Nov 22 '18 at 12:07











  • Jeroen Mostert Test expected to be passed always. This is just synthetic example to emulate fail at first run. So, if run by some reason failed, I need to rerun whole test, and only if it failed for the second time, the result should be failed.

    – Vladimir
    Nov 22 '18 at 12:14






  • 2





    Consider fixing the code so it doesn't fail the first time. If the tests are sufficiently brittle that they're "expected to possibly fail the first time", that's not a good thing! You should use this as an opportunity to make the code reliable enough to test (by waiting on a server to become available or somesuch), not as an incentive to change the tests. If you really need this you should probably set up an external test runner/build server that can invoke the whole set of tests (with vstest.console.exe for example) that applies this "retry logic" based on whether any test failed.

    – Jeroen Mostert
    Nov 22 '18 at 12:19













  • Again, the example is synthetic. There are not a "unit tests". Real tests are complex and have UI search methods and other work with a system and network. In a big test suite there's no 100% confidence that everything will be fine during test execution. That's why some progressive test frameworks like NUnit have implemented "retry" logic. Unfortunately, NUnit is not compatable with Coded UI tests, which we use.

    – Vladimir
    Nov 22 '18 at 12:40











  • Consider just using two test projects -- MSTest for the coded UI and NUnit or whatever else you prefer for the other. Otherwise you'll probably keep trying to stick a square peg in a round hole. You may need a bit of plumbing to get both test projects to run for one solution, but that still sounds simpler than trying to change MSTest at its core. If you're stuck with MSTest (for whatever reason), one option might be T4 templates to auto-generate scaffolding for the test classes so they can be retried without having to write code for it. You can log the extra attempts in the test context.

    – Jeroen Mostert
    Nov 22 '18 at 12:50














0












0








0








Unfortunately, there's no native test rerun logic for MStest / VStest



I'm trying to implement a custom logic like this:



Test part:



    static int testNum = 1;

[TestMethod]
public void RerunTestOnce_Test()
{
testNum = testNum + 1;
Console.WriteLine("Test started");
Assert.IsTrue(testNum == 3, $"Test Failed with number {testNum}");

}


This test should fail for the first time, and pass for the second, when testNum reach value 3.



UP: This is a synthetic example to emulate fail at first run. Real tests are complex and have UI search methods and other work with a system and network, and there's no confidence that everything will be fine during a big & long test suite.



There is a special method for this - RerunTestOnce(), called in TestCleanup:



    [TestCleanup]
public void TestCleanup()
{
TestHelper.RerunTestOnce(TestContext, this);
}


And here is implementation of RerunTestOnce in test helper class.
In it, using Reflection & TestContext we get names of test method and initialize method, and run them again:



 public static void RerunTestOnce(TestContext testContext, object testInstance)
{
if (testContext.CurrentTestOutcome == UnitTestOutcome.Failed)
{
var type = testInstance.GetType();
if (type != null)
{
var testMethod = type.GetMethod(testContext.TestName);
var initMethod = type.GetMethods().SingleOrDefault(m=>m.CustomAttributes.SingleOrDefault(a=>a.AttributeType.Name == "TestInitializeAttribute")!= null);
var cleanupMethod = type.GetMethods().SingleOrDefault(m => m.CustomAttributes.SingleOrDefault(a => a.AttributeType.Name == "TestCleanupAttribute") != null);

Console.WriteLine($"[WARNING] Method [{testMethod}] was failed in first attempt. Trying to rerun...");
try
{
initMethod.Invoke(testInstance, null);
testMethod.Invoke(testInstance, null);
}
catch
{
Console.WriteLine($"[ERROR] Method [{testMethod}] was failed in second attempt. Rerun finished.");
}
}
}
}


Everything is ok, on the second attempt test method passes, but in the end I see Failed result and assert error message from first attempt:



Test Failed - RerunTestOnce_Test
Message: Assert.IsTrue failed. Test Failed with number 2


How and when MSTest creates test result - is it possible to update test result after second attempt to last result?










share|improve this question
















Unfortunately, there's no native test rerun logic for MStest / VStest



I'm trying to implement a custom logic like this:



Test part:



    static int testNum = 1;

[TestMethod]
public void RerunTestOnce_Test()
{
testNum = testNum + 1;
Console.WriteLine("Test started");
Assert.IsTrue(testNum == 3, $"Test Failed with number {testNum}");

}


This test should fail for the first time, and pass for the second, when testNum reach value 3.



UP: This is a synthetic example to emulate fail at first run. Real tests are complex and have UI search methods and other work with a system and network, and there's no confidence that everything will be fine during a big & long test suite.



There is a special method for this - RerunTestOnce(), called in TestCleanup:



    [TestCleanup]
public void TestCleanup()
{
TestHelper.RerunTestOnce(TestContext, this);
}


And here is implementation of RerunTestOnce in test helper class.
In it, using Reflection & TestContext we get names of test method and initialize method, and run them again:



 public static void RerunTestOnce(TestContext testContext, object testInstance)
{
if (testContext.CurrentTestOutcome == UnitTestOutcome.Failed)
{
var type = testInstance.GetType();
if (type != null)
{
var testMethod = type.GetMethod(testContext.TestName);
var initMethod = type.GetMethods().SingleOrDefault(m=>m.CustomAttributes.SingleOrDefault(a=>a.AttributeType.Name == "TestInitializeAttribute")!= null);
var cleanupMethod = type.GetMethods().SingleOrDefault(m => m.CustomAttributes.SingleOrDefault(a => a.AttributeType.Name == "TestCleanupAttribute") != null);

Console.WriteLine($"[WARNING] Method [{testMethod}] was failed in first attempt. Trying to rerun...");
try
{
initMethod.Invoke(testInstance, null);
testMethod.Invoke(testInstance, null);
}
catch
{
Console.WriteLine($"[ERROR] Method [{testMethod}] was failed in second attempt. Rerun finished.");
}
}
}
}


Everything is ok, on the second attempt test method passes, but in the end I see Failed result and assert error message from first attempt:



Test Failed - RerunTestOnce_Test
Message: Assert.IsTrue failed. Test Failed with number 2


How and when MSTest creates test result - is it possible to update test result after second attempt to last result?







c# visual-studio mstest vstest






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 22 '18 at 12:44







Vladimir

















asked Nov 22 '18 at 11:59









VladimirVladimir

129211




129211








  • 1





    Why jump through all these hoops? "This should be done three times, succeeding the first time and failing the second" is part of the logic of your code, and should be expressed clearly as such in the test itself, not as a re-run of the test method. You can use something like Fluent Assertions to express this succinctly (.Should().[Not]Throw()) and wrap the whole thing as a method that takes an Action delegate if you need to reuse this logic.

    – Jeroen Mostert
    Nov 22 '18 at 12:07











  • Jeroen Mostert Test expected to be passed always. This is just synthetic example to emulate fail at first run. So, if run by some reason failed, I need to rerun whole test, and only if it failed for the second time, the result should be failed.

    – Vladimir
    Nov 22 '18 at 12:14






  • 2





    Consider fixing the code so it doesn't fail the first time. If the tests are sufficiently brittle that they're "expected to possibly fail the first time", that's not a good thing! You should use this as an opportunity to make the code reliable enough to test (by waiting on a server to become available or somesuch), not as an incentive to change the tests. If you really need this you should probably set up an external test runner/build server that can invoke the whole set of tests (with vstest.console.exe for example) that applies this "retry logic" based on whether any test failed.

    – Jeroen Mostert
    Nov 22 '18 at 12:19













  • Again, the example is synthetic. There are not a "unit tests". Real tests are complex and have UI search methods and other work with a system and network. In a big test suite there's no 100% confidence that everything will be fine during test execution. That's why some progressive test frameworks like NUnit have implemented "retry" logic. Unfortunately, NUnit is not compatable with Coded UI tests, which we use.

    – Vladimir
    Nov 22 '18 at 12:40











  • Consider just using two test projects -- MSTest for the coded UI and NUnit or whatever else you prefer for the other. Otherwise you'll probably keep trying to stick a square peg in a round hole. You may need a bit of plumbing to get both test projects to run for one solution, but that still sounds simpler than trying to change MSTest at its core. If you're stuck with MSTest (for whatever reason), one option might be T4 templates to auto-generate scaffolding for the test classes so they can be retried without having to write code for it. You can log the extra attempts in the test context.

    – Jeroen Mostert
    Nov 22 '18 at 12:50














  • 1





    Why jump through all these hoops? "This should be done three times, succeeding the first time and failing the second" is part of the logic of your code, and should be expressed clearly as such in the test itself, not as a re-run of the test method. You can use something like Fluent Assertions to express this succinctly (.Should().[Not]Throw()) and wrap the whole thing as a method that takes an Action delegate if you need to reuse this logic.

    – Jeroen Mostert
    Nov 22 '18 at 12:07











  • Jeroen Mostert Test expected to be passed always. This is just synthetic example to emulate fail at first run. So, if run by some reason failed, I need to rerun whole test, and only if it failed for the second time, the result should be failed.

    – Vladimir
    Nov 22 '18 at 12:14






  • 2





    Consider fixing the code so it doesn't fail the first time. If the tests are sufficiently brittle that they're "expected to possibly fail the first time", that's not a good thing! You should use this as an opportunity to make the code reliable enough to test (by waiting on a server to become available or somesuch), not as an incentive to change the tests. If you really need this you should probably set up an external test runner/build server that can invoke the whole set of tests (with vstest.console.exe for example) that applies this "retry logic" based on whether any test failed.

    – Jeroen Mostert
    Nov 22 '18 at 12:19













  • Again, the example is synthetic. There are not a "unit tests". Real tests are complex and have UI search methods and other work with a system and network. In a big test suite there's no 100% confidence that everything will be fine during test execution. That's why some progressive test frameworks like NUnit have implemented "retry" logic. Unfortunately, NUnit is not compatable with Coded UI tests, which we use.

    – Vladimir
    Nov 22 '18 at 12:40











  • Consider just using two test projects -- MSTest for the coded UI and NUnit or whatever else you prefer for the other. Otherwise you'll probably keep trying to stick a square peg in a round hole. You may need a bit of plumbing to get both test projects to run for one solution, but that still sounds simpler than trying to change MSTest at its core. If you're stuck with MSTest (for whatever reason), one option might be T4 templates to auto-generate scaffolding for the test classes so they can be retried without having to write code for it. You can log the extra attempts in the test context.

    – Jeroen Mostert
    Nov 22 '18 at 12:50








1




1





Why jump through all these hoops? "This should be done three times, succeeding the first time and failing the second" is part of the logic of your code, and should be expressed clearly as such in the test itself, not as a re-run of the test method. You can use something like Fluent Assertions to express this succinctly (.Should().[Not]Throw()) and wrap the whole thing as a method that takes an Action delegate if you need to reuse this logic.

– Jeroen Mostert
Nov 22 '18 at 12:07





Why jump through all these hoops? "This should be done three times, succeeding the first time and failing the second" is part of the logic of your code, and should be expressed clearly as such in the test itself, not as a re-run of the test method. You can use something like Fluent Assertions to express this succinctly (.Should().[Not]Throw()) and wrap the whole thing as a method that takes an Action delegate if you need to reuse this logic.

– Jeroen Mostert
Nov 22 '18 at 12:07













Jeroen Mostert Test expected to be passed always. This is just synthetic example to emulate fail at first run. So, if run by some reason failed, I need to rerun whole test, and only if it failed for the second time, the result should be failed.

– Vladimir
Nov 22 '18 at 12:14





Jeroen Mostert Test expected to be passed always. This is just synthetic example to emulate fail at first run. So, if run by some reason failed, I need to rerun whole test, and only if it failed for the second time, the result should be failed.

– Vladimir
Nov 22 '18 at 12:14




2




2





Consider fixing the code so it doesn't fail the first time. If the tests are sufficiently brittle that they're "expected to possibly fail the first time", that's not a good thing! You should use this as an opportunity to make the code reliable enough to test (by waiting on a server to become available or somesuch), not as an incentive to change the tests. If you really need this you should probably set up an external test runner/build server that can invoke the whole set of tests (with vstest.console.exe for example) that applies this "retry logic" based on whether any test failed.

– Jeroen Mostert
Nov 22 '18 at 12:19







Consider fixing the code so it doesn't fail the first time. If the tests are sufficiently brittle that they're "expected to possibly fail the first time", that's not a good thing! You should use this as an opportunity to make the code reliable enough to test (by waiting on a server to become available or somesuch), not as an incentive to change the tests. If you really need this you should probably set up an external test runner/build server that can invoke the whole set of tests (with vstest.console.exe for example) that applies this "retry logic" based on whether any test failed.

– Jeroen Mostert
Nov 22 '18 at 12:19















Again, the example is synthetic. There are not a "unit tests". Real tests are complex and have UI search methods and other work with a system and network. In a big test suite there's no 100% confidence that everything will be fine during test execution. That's why some progressive test frameworks like NUnit have implemented "retry" logic. Unfortunately, NUnit is not compatable with Coded UI tests, which we use.

– Vladimir
Nov 22 '18 at 12:40





Again, the example is synthetic. There are not a "unit tests". Real tests are complex and have UI search methods and other work with a system and network. In a big test suite there's no 100% confidence that everything will be fine during test execution. That's why some progressive test frameworks like NUnit have implemented "retry" logic. Unfortunately, NUnit is not compatable with Coded UI tests, which we use.

– Vladimir
Nov 22 '18 at 12:40













Consider just using two test projects -- MSTest for the coded UI and NUnit or whatever else you prefer for the other. Otherwise you'll probably keep trying to stick a square peg in a round hole. You may need a bit of plumbing to get both test projects to run for one solution, but that still sounds simpler than trying to change MSTest at its core. If you're stuck with MSTest (for whatever reason), one option might be T4 templates to auto-generate scaffolding for the test classes so they can be retried without having to write code for it. You can log the extra attempts in the test context.

– Jeroen Mostert
Nov 22 '18 at 12:50





Consider just using two test projects -- MSTest for the coded UI and NUnit or whatever else you prefer for the other. Otherwise you'll probably keep trying to stick a square peg in a round hole. You may need a bit of plumbing to get both test projects to run for one solution, but that still sounds simpler than trying to change MSTest at its core. If you're stuck with MSTest (for whatever reason), one option might be T4 templates to auto-generate scaffolding for the test classes so they can be retried without having to write code for it. You can log the extra attempts in the test context.

– Jeroen Mostert
Nov 22 '18 at 12:50












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