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MSTEST0017: Assertion arguments should be passed in the correct order

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Property Value
Rule ID MSTEST0017
Title Assertion arguments should be passed in the correct order
Category Usage
Fix is breaking or non-breaking Non-breaking
Enabled by default Yes
Default severity Info
Introduced in version 3.4.0

Cause

This rule raises an issue when calls to Assert.AreEqual, Assert.AreNotEqual, Assert.AreSame or Assert.AreNotSame are following one or multiple of the patterns below:

  • actual argument is a constant or literal value
  • actual argument variable starts with expected, _expected or Expected
  • expected or notExpected argument variable starts with actual
  • actual is not a local variable

Rule description

MSTest Assert.AreEqual, Assert.AreNotEqual, Assert.AreSame and Assert.AreNotSame expect the first argument to be the expected/unexpected value and the second argument to be the actual value.

Having the expected value and the actual value in the wrong order will not alter the outcome of the test (succeeds/fails when it should), but the assertion failure will contain misleading information.

How to fix violations

Ensure that that actual and expected/notExpected arguments are passed in the correct order.

When to suppress warnings

Do not suppress a warning from this rule as it would result to misleading output.