github/workflows: Add workflow to build and run unix port on ARM.

Following on from ef16834887, this adds a
coverage build and running of the test suite on an ARM 32-bit Linux-based
architecture.

Signed-off-by: Damien George <damien@micropython.org>

.github/workflows/ports_unix.yml

@@ -200,3 +200,17 @@ jobs:
     - name: Print failures
       if: failure()
       run: tests/run-tests.py --print-failures
+
+  qemu_arm:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install packages
+      run: source tools/ci.sh && ci_unix_qemu_arm_setup
+    - name: Build
+      run: source tools/ci.sh && ci_unix_qemu_arm_build
+    - name: Run main test suite
+      run: source tools/ci.sh && ci_unix_qemu_arm_run_tests
+    - name: Print failures
+      if: failure()
+      run: tests/run-tests.py --print-failures

tools/ci.sh

@@ -300,6 +300,12 @@ CI_UNIX_OPTS_QEMU_MIPS=(
     LDFLAGS_EXTRA="-static"
 )
 
+CI_UNIX_OPTS_QEMU_ARM=(
+    CROSS_COMPILE=arm-linux-gnueabi-
+    VARIANT=coverage
+    MICROPY_STANDALONE=1
+)
+
 function ci_unix_build_helper {
     make ${MAKEOPTS} -C mpy-cross
     make ${MAKEOPTS} -C ports/unix "$@" submodules
@@ -506,6 +512,25 @@ function ci_unix_qemu_mips_run_tests {
     (cd tests && MICROPY_MICROPYTHON=../ports/unix/micropython-coverage ./run-tests.py --exclude 'vfs_posix.py' --exclude 'ffi_(callback|float|float2).py')
 }
 
+function ci_unix_qemu_arm_setup {
+    sudo apt-get update
+    sudo apt-get install gcc-arm-linux-gnueabi g++-arm-linux-gnueabi
+    sudo apt-get install qemu-user
+    qemu-arm --version
+}
+
+function ci_unix_qemu_arm_build {
+    ci_unix_build_helper "${CI_UNIX_OPTS_QEMU_ARM[@]}"
+}
+
+function ci_unix_qemu_arm_run_tests {
+    # Issues with ARM tests:
+    # - (i)listdir does not work, it always returns the empty list (it's an issue with the underlying C call)
+    export QEMU_LD_PREFIX=/usr/arm-linux-gnueabi
+    file ./ports/unix/micropython-coverage
+    (cd tests && MICROPY_MICROPYTHON=../ports/unix/micropython-coverage ./run-tests.py --exclude 'vfs_posix.py')
+}
+
 ########################################################################################
 # ports/windows