Risky Tests

Introduction

PHPUnit can be made to do some additional checks while it runs some tests on the background. Some of these additional checks are explored below

#Useless Tests

PHPUnit is by default strict about tests that do not test anything. This check can be disabled by using the `--don't-report-useless-tests` option on the command line or by setting `beStrictAboutTestsThatDoNotTestAnything="false"` in PHPUnit’s XML configuration file.

A test that does not perform an assertion will be marked as risky when this check is enabled. Expectations on mock objects or annotations such as @expectedException count as an assertion.

#Unintentionally Covered Code

PHPUnit can be strict about unintentionally covered code. This check can be enabled by using the `--strict-coverage` option on the command line or by setting `beStrictAboutCoversAnnotation="true"` in PHPUnit’s XML configuration file.

A test that is annotated with `@covers` and executes code that is not listed using a `@covers` or `@uses` annotation will be marked as risky when this check is enabled.

#Output During Test Execution

PHPUnit can be made to be strict about output during tests. This check can be enabled by using the `--disallow-test-output` option on the command line or by setting `beStrictAboutOutputDuringTests="true"` in PHPUnit’s XML configuration file.

A test that emits output, for instance by invoking print in either the test code or the tested code, will be marked as risky when this check is enabled.

#Test Execution Timeout

A time limit can be enforced for the execution of a test if the `PHP_Invoker` package is installed and the `pcntl` extension is available. The enforcing of this time limit can be enabled by using the `--enforce-time-limit` option on the command line or by setting `enforceTimeLimit="true"` in PHPUnit’s XML configuration file.

A test annotated with `@large` will fail if it takes longer than 60 seconds to execute. This timeout is configurable via the `timeoutForLargeTests` attribute in the XML configuration file.

A test annotated with @medium will fail if it takes longer than 10 seconds to execute. This timeout is configurable via the `timeoutForMediumTests` attribute in the XML configuration file.

A test annotated with @small will fail if it takes longer than 1 second to execute. This timeout is configurable via the `timeoutForSmallTests` attribute in the XML configuration file.

Tests need to be explicitly annotated by either `@small`, `@medium`, or `@large` to enable run time limits.

#Global State Manipulation

PHPUnit can be strict about tests that manipulate global state. This check can be enabled by using the `--strict-global-state` option on the command line or by setting `beStrictAboutChangesToGlobalState="true"` in PHPUnit’s XML configuration file.

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