HARMONI is the ELT’s first light visible and near-infrared (0.5 to 2.45 μm) integral field spectrograph over a range of resolving powers from R~3500 to R~18000. It will provide 4 different spatial scales from 4*4mas to 30*60mas. It can operate in two Adaptive Optics (AO) modes – Single Conjugate AO (including a High Contrast capability) and Laser Tomography AO - or with No AO. The project is preparing for Final Design Reviews. The Integral Field Spectrograph (IFS) is the science instrument operating at 130K. This paper depicts the test tools developed to validate one sub-system, the Integral Field Unit (IFU), developed in Centre de Recherche Astrophysique de Lyon. The IFU is in charge of splitting, slicing and rearranging the rectangular field of view into 4 long slits (~540mm) to feed the 4 spectrographs. The tools are measuring position, angular deviation, wavefront or geometry of the field at ambient and operating temperature. Their design and validation are described with measurements on prototypes in our test cryostat. Their use for the final validation of the IFU performances is also addressed.
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