tests/PptxTools.Tests/TestPptxHelper.cs is the shared test-fixture builder for pptx-tools. Use it whenever a test needs a valid presentation with realistic combinations of titles, body placeholders, and images.

Pattern

Use TestPptxHelper.CreateMinimalPresentation(...) for single-slide happy-path tests.
Use TestPptxHelper.CreatePresentation(path, slides) with TestSlideDefinition for richer fixtures.
Model text content with TestTextShapeDefinition, using PlaceholderType = PlaceholderValues.Body when you want bullet-like talking-point behavior.
Set IncludeImage = true to validate image-only slides without hand-building picture relationships.
Keep tool tests thin and let service tests cover behavior details.

Example

TestPptxHelper.CreatePresentation(path,
[
    new TestSlideDefinition
    {
        TitleText = "Launch Plan",
        TextShapes =
        [
            new TestTextShapeDefinition
            {
                PlaceholderType = PlaceholderValues.Body,
                Paragraphs =
                [
                    "Ship the MCP tool",
                    "Validate output"
                ]
            }
        ]
    },
    new TestSlideDefinition
    {
        IncludeImage = true
    }
]);

Anti-Patterns

Do not hand-build OpenXML slide trees inside individual tests when the helper can express the fixture.
Do not use invalid placeholder or image setup; start from the helper's valid presentation scaffold.