NUnit1015

The source type does not implement I(Async)Enumerable

Topic	Value
Id	NUnit1015
Severity	Error
Enabled	True
Category	Structure
Code	TestCaseSourceUsesStringAnalyzer

Description

The source type must implement I(Async)Enumerable in order to provide test cases.

Motivation

To prevent tests that will fail at runtime due to improper construction.

How to fix violations

Example Violation

public class MyTestClass
{
    [TestCaseSource(typeof(DivideCases))]
    public void DivideTest(int n, int d, int q)
    {
        ClassicAssert.AreEqual(q, n / d);
    }
}

class DivideCases
{
    public IEnumerator GetData()
    {
        yield return new object[] { 12, 3, 4 };
        yield return new object[] { 12, 2, 6 };
        yield return new object[] { 12, 4, 3 };
    }
}

Explanation

In the sample above, the class DivideCases does not implement IEnumerable nor IAsyncEnumerable

However, source types specified by TestCaseSource must implement IEnumerable or IAsyncEnumerable.

Fix

Make the source type implement IEnumerable or IAsyncEnumerable

public class MyTestClass
{
    [TestCaseSource(typeof(DivideCases))]
    public void DivideTest(int n, int d, int q)
    {
        ClassicAssert.AreEqual(q, n / d);
    }
}

class DivideCases : IEnumerable
{
    public IEnumerator GetEnumerator()
    {
        yield return new object[] { 12, 3, 4 };
        yield return new object[] { 12, 2, 6 };
        yield return new object[] { 12, 4, 3 };
    }
}

Configure severity

Via ruleset file

Configure the severity per project, for more info see MSDN.

Via .editorconfig file

# NUnit1015: The source type does not implement I(Async)Enumerable
dotnet_diagnostic.NUnit1015.severity = chosenSeverity

where chosenSeverity can be one of none, silent, suggestion, warning, or error.

Via #pragma directive

#pragma warning disable NUnit1015 // The source type does not implement I(Async)Enumerable
Code violating the rule here
#pragma warning restore NUnit1015 // The source type does not implement I(Async)Enumerable

Or put this at the top of the file to disable all instances.

#pragma warning disable NUnit1015 // The source type does not implement I(Async)Enumerable

Via attribute [SuppressMessage]

[System.Diagnostics.CodeAnalysis.SuppressMessage("Structure",
    "NUnit1015:The source type does not implement I(Async)Enumerable",
    Justification = "Reason...")]