testing-guide

name	testing-guide
description	Writes or reviews unit tests for Syncfusion Toolkit for .NET MAUI controls. Covers what to test, impossible scenarios, naming conventions, and skipped test documentation. Can be invoked standalone or called from any agent (issue-resolver, test-writer, etc.).

Skill: Testing Guide

Write or review xUnit tests for a Syncfusion Toolkit for .NET MAUI control change.

When to Use This Skill

• ✅ Writing new tests after a bug fix or feature
• ✅ Reviewing whether existing tests cover a change adequately
• ✅ Called from another agent to handle the test-writing step

---

Inputs Required

The caller (agent or user) must provide:

Input	Description
Control area	e.g., Chart, Calendar, Popup
What changed	A summary of the fix or feature that was implemented
Affected files	Source files that were modified

---

Step 1: Locate the Test File

maui/tests/Syncfusion.Maui.Toolkit.UnitTest/{ControlArea}/

find maui/tests/Syncfusion.Maui.Toolkit.UnitTest/{ControlArea}/ -name "*.cs" | head -20

If no test file exists for the control area, create one following the naming pattern of adjacent test files.

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Step 2: What to Test

Add tests for all scenarios that are possible given the control's design:

Change Type	What to Cover
Bug fix	Reproduce the bug — must fail without fix, pass with fix
Feature	Validate new behavior end-to-end
Edge cases	Boundary values, null inputs where nullable is allowed, default state, repeated calls

Naming convention: MethodOrProperty_Scenario_ExpectedBehavior

[Fact]
public void SomeProperty_WhenSetToValue_ShouldUpdateBehavior()
{
	// Arrange
	var control = new SomeControl();

	// Act
	control.SomeProperty = expectedValue;

	// Assert
	Assert.Equal(expectedValue, control.InternalState);
}

Use hard tabs for indentation. Do NOT use the private keyword.

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Step 3: What NOT to Test (Impossible Scenarios)

Do NOT write tests for scenarios that are architecturally impossible.

A scenario is impossible if:

Reason	Example
Type system prevents the state	Testing null on a non-nullable required property
Constructor guarantees initialization	Testing "uninitialized" state on a property set in the constructor
Code path can never be reached	A branch guarded by a condition always true/false by design
Platform API unavailable in unit test context	Testing a renderer or native handler requiring a live platform runtime
Contradicts control invariants	Setting an index out of range when the setter clamps to valid range

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Step 4: Document Skipped Scenarios

For each impossible scenario, add a row to ## Skipped Tests in the caller's state file (or report directly to the user if invoked standalone):

## Skipped Tests
| Scenario | Reason Impossible |
|----------|-------------------|
| `Items_WhenNull_ShouldNotThrow` | `Items` is initialized in constructor; can never be null |
| `OnPlatformRenderer_WhenDetached` | Requires native platform runtime; not testable in xUnit |

---

Step 5: Build and Run Tests

# Build first to catch compile errors
dotnet build ./Syncfusion.Maui.Toolkit.sln

# Run all unit tests
dotnet test maui/tests/Syncfusion.Maui.Toolkit.UnitTest/

# Run tests filtered to this control area
dotnet test maui/tests/Syncfusion.Maui.Toolkit.UnitTest/ --filter "FullyQualifiedName~{ControlArea}"

Report results to the caller or user: tests passed ✅, failed ❌, or skipped with reason.