[Repo Assist] test: add DefinitionPath.Parse unit tests and PreferNullable coverage

[github-actions]

🤖 This is an automated pull request from Repo Assist, an AI assistant.

Summary

Adds 21 new unit tests covering two previously-untested areas:

1. DefinitionPath.Parse (new file: v3/Schema.DefinitionPathTests.fs, 16 tests)

DefinitionPath.Parse is the function that splits a JSON Reference path (e.g. #/components/schemas/My.Namespace.TypeName) into a namespace list, a raw type name, and a PascalCase candidate name. It has zero existing tests. The new tests cover:

• Simple (un-namespaced) names → empty namespace, identity type name
• PascalCase candidate via nicePascalName
• One-level namespace extraction (My.Pet → ["My"], "Pet")
• Multi-level namespace extraction (2, 3, and 4 levels deep)
• Names containing hyphens (non-dot separator — no spurious namespace split)
• Error cases: definition not starting with #/components/schemas/ prefix, Swagger 2 #/definitions/ path

2. PreferNullable=true type mapping (additions to v3/Schema.TypeMappingTests.fs, 5 tests)

When DefinitionCompiler is constructed with provideNullable=true, optional value-type properties should produce Nullable<T> instead of Option<T>. These tests were entirely missing:

• optional boolean → Nullable<bool>
• optional integer → Nullable<int32>
• optional int64 → Nullable<int64>
• required integer → int32 (unchanged — nullable wrapping is only for optional)
• optional string → string (reference types are never wrapped, regardless of mode)

3. compilePropertyTypeWith helper (additions to v3/Schema.TestHelpers.fs)

New helper that mirrors compilePropertyType but exposes the provideNullable flag, enabling the PreferNullable tests above and any future tests that need non-default compiler options.

Rationale

DefinitionPath.Parse is called on every $ref encountered in a schema, making it load-bearing code. Adding regression tests protects against future changes that inadvertently alter its namespace-splitting logic. The PreferNullable tests document and protect a user-facing static parameter.

Test Status

✅ Build: succeeded (dotnet build)
✅ Tests: 316/316 passed, 0 failed — up from 295 (21 new tests)
(dotnet tests/SwaggerProvider.Tests/bin/Release/net10.0/SwaggerProvider.Tests.dll)

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[Copilot]

Pull request overview

Adds new unit tests to improve coverage of OpenAPI v3 schema compilation helpers, specifically around $ref definition-path parsing and PreferNullable=true behavior in type mapping.

Changes:

• Add a new v3 test module covering DefinitionPath.Parse (prefix handling, namespace splitting, and failure cases).
• Extend v3 type-mapping tests to cover PreferNullable=true for optional value types (Nullable<T> vs Option<T>).
• Add a new compilePropertyTypeWith helper to compile schemas under non-default DefinitionCompiler options.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
tests/SwaggerProvider.Tests/v3/Schema.TypeMappingTests.fs	Adds PreferNullable=true unit tests for optional value-type property mapping.
tests/SwaggerProvider.Tests/v3/Schema.TestHelpers.fs	Introduces compilePropertyTypeWith to compile schemas with configurable provideNullable.
tests/SwaggerProvider.Tests/v3/Schema.DefinitionPathTests.fs	New test suite validating DefinitionPath.Parse behavior and error cases.
tests/SwaggerProvider.Tests/SwaggerProvider.Tests.fsproj	Includes the new Schema.DefinitionPathTests.fs in the test project compile list.

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[sergey-tihon]

/repo-assist address inline review comments

[github-actions]

✗ Repo Assist encountered failed, see workflow run.

[sergey-tihon]

@copilot address inline review comments (don't update pr description)

[Copilot]

@copilot address inline review comments (don't update pr description)

Addressed all three inline review comments in commit 9c88958:

1. compilePropertyTypeWith diagnostic handling — Added the same readResult.Diagnostic.Errors check used in compileV3Schema, including the same error message format and failwithf pattern, so parse errors/warnings surface consistently.

2. Nullable type assertions — Replaced all three typedefof<Nullable<_>>.MakeGenericType(...) calls with direct typeof<Nullable<bool>>, typeof<Nullable<int32>>, and typeof<Nullable<int64>>.

3. Misleading comment — Reworded per the suggestion: "The dot before 'my-type' is in the scanned definition-name segment after the prefix; the hyphen stops the scan, so LastIndexOf('.') finds that dot."

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

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