[Buildroot] [WIP: python3 bug] support/testing: add python3 multiprocessing pool test

[Romain Naour]

While running some python script on aarch64 board, it get stuck while
imporing multiprocessing Pool:

from multiprocessing import Pool

This issue seems specific to aarch64.

Signed-off-by: Romain Naour <romain.naour at gmail.com>
---
 .../sample_python_multiprocessing_pool.py     |  3 ++
 .../test_python_multiprocessing_pool.py       | 45 +++++++++++++++++++
 2 files changed, 48 insertions(+)
 create mode 100644 support/testing/tests/package/sample_python_multiprocessing_pool.py
 create mode 100644 support/testing/tests/package/test_python_multiprocessing_pool.py

diff --git a/support/testing/tests/package/sample_python_multiprocessing_pool.py b/support/testing/tests/package/sample_python_multiprocessing_pool.py
new file mode 100644
index 0000000000..df450e4b71
--- /dev/null
+++ b/support/testing/tests/package/sample_python_multiprocessing_pool.py
@@ -0,0 +1,3 @@
+# This import can be stuck on aarch64 with python3 (3.7.4)
+# The test should fail when the timout occurred.
+from multiprocessing import Pool
diff --git a/support/testing/tests/package/test_python_multiprocessing_pool.py b/support/testing/tests/package/test_python_multiprocessing_pool.py
new file mode 100644
index 0000000000..349a91368c
--- /dev/null
+++ b/support/testing/tests/package/test_python_multiprocessing_pool.py
@@ -0,0 +1,45 @@
+import os
+
+from tests.package.test_python import TestPythonPackageBase
+
+class TestPythonMultiprocessingPool(TestPythonPackageBase):
+    sample_scripts = ["tests/package/sample_python_multiprocessing_pool.py"]
+    timeout = 60
+
+    # Remove "-serial", "stdio", from testing/infra/emulator.py before running the test.
+    # Otherwise you will get the following error:
+    # qemu-system-aarch64: -serial stdio: cannot use stdio by multiple character devices
+    # qemu-system-aarch64: -serial stdio: could not connect serial device to character backend 'stdio'
+
+    def login(self):
+        kern = os.path.join(self.builddir, "images", "Image")
+        ext4_file = os.path.join(self.builddir, "images", "rootfs.ext4")
+
+        self.emulator.boot(arch="aarch64",
+                        kernel=kern,
+                        options=["-append","root=/dev/vda console=ttyAMA0", "-M", "virt", "-cpu", "cortex-a53", "-nographic", "-smp", "1", "-netdev", "user,id=eth0", "-device", "virtio-net-device,netdev=eth0", "-drive", "file=" + ext4_file + ",if=none,format=raw,id=hd0", "-device", "virtio-blk-device,drive=hd0"])
+        self.emulator.login()
+
+# Test with Glibc and MultiprocessingPool
+class TestPythonPy3GlibcMultiprocessingPool(TestPythonMultiprocessingPool):
+    __test__ = True
+    config = \
+        """
+	BR2_aarch64=y
+	BR2_cortex_a53=y
+	BR2_TOOLCHAIN_EXTERNAL=y
+	BR2_SYSTEM_DHCP="eth0"
+	BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
+	BR2_TARGET_ROOTFS_EXT2=y
+	BR2_TARGET_ROOTFS_EXT2_4=y
+	# BR2_TARGET_ROOTFS_TAR is not set
+	BR2_LINUX_KERNEL=y
+	BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+	BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.16"
+	BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
+	BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/aarch64-virt/linux.config"
+	BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y
+        BR2_PACKAGE_PYTHON3=y
+        BR2_TARGET_ROOTFS_CPIO=y
+        # BR2_TARGET_ROOTFS_TAR is not set
+        """
-- 
2.21.0