tools/mpremote/tests: Add tests for errno behavior.

Signed-off-by: Anson Mansfield <amansfield@mantaro.com>

tools/mpremote/tests/test_errno.sh

@@ -0,0 +1,38 @@
+#!/bin/bash
+set -e
+
+# Special ErrorFS so the test can induce arbitrary filesystem errors.
+cat << EOF > "${TMP}/fs.py"
+import os, vfs, errno
+
+class ErrorFS:
+    def mount(self, *a, **k):
+        pass
+    def umount(self, *a, **k):
+        pass
+    def chdir(self, *a, **k):
+        pass
+    def open(self, *a, **k):
+        raise self.error
+
+fs = ErrorFS()
+vfs.mount(fs, '/fs')
+os.chdir('/fs')
+EOF
+
+$MPREMOTE run "${TMP}/fs.py"
+
+echo -----
+$MPREMOTE resume exec "fs.error = Exception()"
+(
+  $MPREMOTE resume cat :Exception.py || echo "expect error"
+) 2> >(head -n1 >&2) # discard traceback specifics but keep main error message
+
+for errno in ENOENT EISDIR EEXIST ENODEV EINVAL EPERM EOPNOTSUPP ; do
+echo -----
+$MPREMOTE resume exec "fs.error = OSError(errno.$errno, '')"
+$MPREMOTE resume cat :$errno.py || echo "expect error"
+done
+
+echo -----
+$MPREMOTE resume exec "vfs.umount('/fs')"

tools/mpremote/tests/test_errno.sh.exp

@@ -0,0 +1,25 @@
+-----
+mpremote: Error with transport:
+expect error
+-----
+mpremote: cat: ENOENT.py: No such file or directory.
+expect error
+-----
+mpremote: cat: EISDIR.py: Is a directory.
+expect error
+-----
+mpremote: cat: EEXIST.py: File exists.
+expect error
+-----
+mpremote: cat: ENODEV.py: No such device.
+expect error
+-----
+mpremote: cat: EINVAL.py: Invalid argument.
+expect error
+-----
+mpremote: cat: EPERM.py: Operation not permitted.
+expect error
+-----
+mpremote: cat: EOPNOTSUPP.py: Operation not supported.
+expect error
+-----