tests: drivers: Add QSPI driver test with single line mode

This test is introduced due to customer bug report:
Failure on QSPI flash used in non-Quad mode (single line)

Signed-off-by: Bartosz Miller <bartosz.miller@nordicsemi.no>

Author: nordic-bami

tests/drivers/nrf_qspi_flash/CMakeLists.txt

@@ -0,0 +1,19 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+if(NOT SYSBUILD)
+	message(FATAL_ERROR
+		" This is a multi-image application that should be built using sysbuild.\n"
+		" Add --sysbuild argument to west build command to prepare all the images.")
+endif()
+
+project(nrf_qspi_flash)
+
+target_sources(app PRIVATE ${ZEPHYR_BASE}/samples/drivers/spi_flash/src/main.c)

tests/drivers/nrf_qspi_flash/flash_cfg/mx25r64_single_line.overlay

@@ -0,0 +1,11 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+&mx25r64 {
+	status="okay";
+	readoc="fastread";
+	writeoc="pp";
+};

tests/drivers/nrf_qspi_flash/prj.conf

@@ -0,0 +1,8 @@
+CONFIG_FLASH=y
+CONFIG_ASSERT=y
+
+CONFIG_PRINTK=y
+CONFIG_LOG=y
+CONFIG_CONSOLE=y
+CONFIG_UART_CONSOLE=y
+CONFIG_SERIAL=y

tests/drivers/nrf_qspi_flash/testcase.yaml

@@ -0,0 +1,44 @@
+common:
+  sysbuild: true
+  depends_on: spi
+
+tests:
+  tests.drivers.nrf_qspi_flash.qspi_multi_line_mode:
+    tags:
+      - ci_build
+      - flash
+      - spi
+    platform_allow:
+      - nrf52840dk/nrf52840
+      - nrf5340dk/nrf5340/cpuapp
+    integration_platforms:
+      - nrf52840dk/nrf52840
+      - nrf5340dk/nrf5340/cpuapp
+    harness: console
+    harness_config:
+      type: multi_line
+      ordered: true
+      regex:
+        - ".*Flash erase succeeded.*"
+        - ".*Data read matches data written. Good.*"
+
+  tests.drivers.nrf_qspi_flash.qspi_single_line_mode:
+    tags:
+      - ci_build
+      - flash
+      - spi
+    platform_allow:
+      - nrf52840dk/nrf52840
+      - nrf5340dk/nrf5340/cpuapp
+    integration_platforms:
+      - nrf52840dk/nrf52840
+      - nrf5340dk/nrf5340/cpuapp
+    extra_args:
+      - EXTRA_DTC_OVERLAY_FILE="flash_cfg/mx25r64_single_line.overlay"
+    harness: console
+    harness_config:
+      type: multi_line
+      ordered: true
+      regex:
+        - ".*Flash erase succeeded.*"
+        - ".*Data read matches data written. Good.*"