Copilot instructions

1---
2applyTo: "**/test/**/*Tests.cs"
3---
4 
5# General Guidelines
6- Use these frameworks: xUnit, Moq, FluentAssertions (existing tests), xUnit Asserts (new tests).
7- For unit tests on Repository classes, use Squadron to create a MongoDB.
8- If there are more than 5 asserts to do on a result, use Snapshooter instead.
9- Use Theories instead of multiple tests.
10- Never use [MemberData].
11 
12# Test Naming Conventions
13- Test class names should end with "Tests" (e.g., UserServiceTests)
14- Test method names should follow the pattern: MethodName_Scenario_ExpectedBehavior
15- Use descriptive names that clearly indicate what is being tested
16- Name the result in the Act part either `result` or `act` when testing for exceptions.
17 
18# Test Data and Setup
19- Mocks: 
20  Define as fields and instantiate directly if possible
21  Pre-configure default behaviour in the constructor when appropriate
22  Use MockBehavior.Strict as default
23- Instantiate the class under test in the constructor of the test class
24- Avoid creating the same test data repeatedly. Instead, use sample data classes.
25- When using Squadron, ensure to re-use the instance by creating a collection fixture
26 
27# Test Structure
28- Follow Arrange-Act-Assert (AAA) pattern in all tests
29- Use separate lines or comments to clearly delineate AAA sections
30- Keep tests focused on a single behavior or scenario
31- Having no or few lines in the Arrange section is preferred.
32 
33# Assertions
34- Use FluentAssertions for consistency reasons for existing tests
35- Use xUnit Asserts in new tests
36 
37# Snapshot Testing
38- Use Snapshooter when testing complex objects with many properties
39- Update snapshots deliberately when behavior changes are intended
40- Review snapshot changes carefully during code reviews
41 
42# Mocking and Dependencies
43- Use clear, descriptive variable names for mocks
44- Avoid defining mocks inside the test method when possible.
45- Verify mock interactions when behavior verification is important
46- When verifying mock interactions, avoid using It.IsAny<T>() if a more specific constraint can be used
47 
48# Error Handling and Exception Testing
49- Test both happy path and error scenarios
50- Use FluentAssertions for exception testing: .Should().ThrowExactly[Async]<ExceptionType>()
51- Verify exception messages and properties when relevant
52- Test error propagation in service layers
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