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MSTEST0083: Use '[ExecutableCondition]' instead of 'File.Exists' checks before 'Process.Start'

Property Value
Rule ID MSTEST0083
Title Use '[ExecutableCondition]' instead of 'File.Exists' checks before 'Process.Start'
Category Usage
Fix is breaking or non-breaking Non-breaking
Enabled by default Yes
Default severity Info
Introduced in version 4.4.0 (preview)
Is there a code fix Yes, for C# only

Important

This analyzer is planned for MSTest 4.4 and is available only in preview builds until MSTest 4.4.0 is released.

Cause

A test method first checks whether an executable exists and returns or calls Assert.Inconclusive when it doesn't, then calls Process.Start with the same executable path.

Rule description

Use [ExecutableCondition] to declare that a test requires an executable. The attribute reports the test as skipped when MSTest can't resolve the executable. An early return incorrectly reports the test as passed, and an imperative check hides the requirement from discovery and reporting tools.

[TestMethod]
public void RunsTool()
{
    if (!File.Exists("tool.exe")) return; // Violation
    Process.Start("tool.exe");
}

The analyzer recognizes a first-statement guard without a meaningful else branch when both File.Exists and the later Process.Start use the same constant executable path.

How to fix violations

Replace the guard with [ExecutableCondition].

[TestMethod]
[ExecutableCondition("tool.exe")]
public void RunsTool() => Process.Start("tool.exe");

A C# code fix replaces the guard with the attribute. Visual Basic reports the diagnostic but doesn't provide an automatic fix.

When to suppress warnings

Suppress the rule when the file check validates data rather than an executable prerequisite, or when the test needs behavior that ExecutableConditionAttribute can't express.

Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable MSTEST0083
// The code that's violating the rule is on this line.
#pragma warning restore MSTEST0083

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.MSTEST0083.severity = none

For more information, see How to suppress code analysis warnings.

See also

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