MSTEST0001: Explicitly enable or disable tests parallelization
| Property | Value |
|---|---|
| Rule ID | MSTEST0001 |
| Title | Explicitly enable or disable tests parallelization |
| Category | Performance |
| Fix is breaking or non-breaking | Non-breaking |
| Enabled by default | Yes |
| Default severity | Info |
| Introduced in version | 3.2.0 |
| Is there a code fix | No |
Cause
The assembly is not marked with [assembly: Parallelize] or [assembly: DoNotParallelize] attribute.
Rule description
By default, MSTest runs tests within the same assembly sequentially, which can lead to severe performance limitations. It is recommended to enable assembly attribute [assembly: Parallelize] to run tests in parallel, or if the assembly is known to not be parallelizable, to use explicitly the assembly level attribute [assembly: DoNotParallelize].
The default configuration of [assembly: Parallelize] is equivalent to [assembly: Parallelize(Scope = ExecutionScope.ClassLevel)], meaning that the parallelization will be set at class level (not method level) and will use as many threads as possible (depending on internal implementation).
How to fix violations
To fix a violation of this rule, add [assembly: Parallelize] or [assembly: DoNotParallelize] attribute. We recommend to use [assembly: Parallelize(Scope = ExecutionScope.MethodLevel)] to have best parallelization.
When to suppress warnings
Do not suppress a warning from this rule. Many libraries can benefit from a massive performance boost when enabling parallelization. When the test application is designed in a way that prevents parallelization, having the attribute explicitly set helps new developers to understand the limitations of the library.
Suppress a warning
Because this rule is reported at the compilation level and not in a .cs or .vb source file, you can't suppress violations to this rule inline or via an .editorconfig file.
To disable the rule for a project, add <NoWarn>$(NoWarn);MSTEST0001</NoWarn> to the project file or Directory.Build.props file.
To control the severity of this rule, you can do it only via a .globalconfig file. For more information, see Configuration files.
is_global = true
dotnet_diagnostic.MSTEST0001.severity = none
For more information, see How to suppress code analysis warnings.
