Assertions & Attributes

This page covers CustomAssert and the environment-aware test attributes.

CustomAssert⌗

CustomAssert is a static class with the null/empty assertions that come up most often, so you don’t have to spell out Assert.True(collection is null || !collection.Any()) every time. Each method throws the same exception type as a failing Assert, so failures read exactly like normal xUnit failures.

Method	Passes when
`NullOrEmpty(IEnumerable?)`	The collection is `null` or has no elements
`NotNullOrEmpty(IEnumerable?)`	The collection is not `null` and has at least one element
`NullOrEmpty(string?)`	The string is `null` or empty
`NotNullOrEmpty(string?)`	The string is not `null` and not empty
`NullOrWhiteSpace(string?)`	The string is `null`, empty, or only white space
`NotNullOrWhiteSpace(string?)`	The string has at least one non-white-space character

CustomAssert.NullOrEmpty(Array.Empty<int>());     // passes
CustomAssert.NullOrEmpty((IEnumerable?)null);      // passes
CustomAssert.NotNullOrEmpty(new[] { 1, 2, 3 });    // passes

CustomAssert.NullOrWhiteSpace("   ");              // passes
CustomAssert.NotNullOrWhiteSpace("value");         // passes

The collection overloads treat null and empty the same way, so a null reference never trips up a NullOrEmpty check.

Environment-aware attributes⌗

Four attributes wrap xUnit’s [Fact] and [Theory] so a test can be skipped based on the active environment or an explicit condition:

Attribute	Wraps	Intended use
`UnitFactAttribute`	`[Fact]`	Unit test
`UnitTheoryAttribute`	`[Theory]`	Data-driven unit test
`FunctionalFactAttribute`	`[Fact]`	Functional / integration test
`FunctionalTheoryAttribute`	`[Theory]`	Data-driven functional test

All four share the same two optional parameters:

UnitFact(EnvironmentType[]? environments = null, bool skipCondition = false)

environments — the environments in which the test must not run. The current environment is read from the ASPNETCORE_ENVIRONMENT variable and compared case-insensitively. When it matches one of the listed environments, the test is skipped with the reason Test can't run on {environment}. null (the default) imposes no environment restriction.
skipCondition — when true, the test is skipped regardless of the environment, with the reason Condition to skip matched.

// Runs everywhere except Production.
[UnitFact([EnvironmentType.Production])]
public void Calculates_totals() { /* ... */ }

// Never runs while the feature flag is off, on any environment.
[FunctionalFact(skipCondition: FeatureFlags.PaymentsDisabled)]
public void Charges_card() { /* ... */ }

// Data-driven test blocked on Staging and Production.
[UnitTheory([EnvironmentType.Staging, EnvironmentType.Production])]
[InlineData(1)]
[InlineData(2)]
public void Validates_input(int value) { /* ... */ }

EnvironmentType comes from ArturRios.Configuration.Enums and defines Local, Development, Staging and Production.

How the skip decision is made⌗

If skipCondition is true, the test is skipped.
Otherwise, if environments is null or empty, the test runs.
Otherwise, the test is skipped when the current ASPNETCORE_ENVIRONMENT matches one of the listed environments.