---
source_files:
  - DataPRO/FftSharp.Test/PowerSpectralDensityShould.cs
generated_at: "2026-04-17T16:30:54.516212+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "cf0aa492a8193a8d"
---

# FftSharp.Test

### Purpose
This module contains unit tests for the `FftSharp` library, specifically validating Power Spectral Density (PSD) calculations using the Welch method. It ensures that the library's FFT frequency generation and PSD calculations match expected results derived from pre-computed CSV data files, verifying mathematical accuracy within a specific tolerance.

### Public Interface
*   **`class PowerSpectralDensityShould`**: A NUnit test fixture containing tests for PSD functionality.
    *   `void BasicWelch_1_RawTestDataShouldParse()`: Verifies that `Raw.csv` parses correctly into two lists of length `304478`.
    *   `void BasicWelch_2_PSDResultsDataShouldParse()`: Verifies that `PSD.csv` parses correctly into two lists of length `2049`.
    *   `void BasicWelch_3_FFTSharpFreqShouldMatchPSDResultFreq()`: Validates that `FftSharp.Transform.FFTfreq` generates frequency axes matching the reference data in `PSD.csv`.
    *   `void BasicWelch_4_TestBasicFlatTopNoOverlap4096Width()`: Validates the `FftSharp.Transform.PSD_Welch` method output against reference PSD data using a Rectangular window.
*   **Private Helpers**:
    *   `