tests/subsys/shell/shell_flash/prj.conf

CONFIG_FLASH=y
CONFIG_FLASH_SHELL=y
CONFIG_SHELL=y
CONFIG_SHELL_BACKEND_SERIAL=n
CONFIG_SHELL_BACKEND_DUMMY=y
CONFIG_SHELL_CMD_BUFF_SIZE=90
CONFIG_SHELL_PRINTF_BUFF_SIZE=15
CONFIG_SHELL_METAKEYS=n
CONFIG_LOG=n
CONFIG_ZTEST=y