support/testing/tests/package/test_python_s3transfer: use ext2 instead of cpio

The CPIO filesystem generated by the test_python_s3transfer test is
too large, and doesn't fit as an initramfs in the 256MB of RAM
available in the versatilepb machine. This causes a "Initramfs
unpacking failed: write error" when booting, and many files being
missing from the root filesystem, ultimately causing the test to fail.

It would make sense to switch all test cases to use ext2 + a
hard-drive, but for now, let's fix the few test cases that are causing
problems.

Fixes:

  https://gitlab.com/buildroot.org/buildroot/-/jobs/2884635126

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[yann.morin.1998@free.fr:
  - drop superfluous# BR2_TARGET_ROOTFS_TAR is not set
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

support/testing/tests/package/test_python_s3transfer.py

@@ -1,4 +1,5 @@
 from tests.package.test_python import TestPythonPackageBase
+import os
 
 
 class TestPythonPy3S3transfer(TestPythonPackageBase):
@@ -7,6 +8,16 @@ class TestPythonPy3S3transfer(TestPythonPackageBase):
         """
         BR2_PACKAGE_PYTHON3=y
         BR2_PACKAGE_PYTHON_S3TRANSFER=y
+        BR2_TARGET_ROOTFS_EXT2=y
+        BR2_TARGET_ROOTFS_EXT2_SIZE="120M"
         """
     sample_scripts = ["tests/package/sample_python_s3transfer.py"]
     timeout = 10
+
+    def login(self):
+        ext2_file = os.path.join(self.builddir, "images", "rootfs.ext2")
+        self.emulator.boot(arch="armv5",
+                           kernel="builtin",
+                           options=["-drive", "file=%s,if=scsi,format=raw" % ext2_file],
+                           kernel_cmdline=["rootwait", "root=/dev/sda"])
+        self.emulator.login()