Account for double slash in legacy bin paths rockstor#2757

in rockstor#2558, we implemented
an automatic conversion of legacy paths to poetry bin paths for rockstor
scripts. This, however, failed for legacy paths that somehow included
double slashes.

This commit updates the pattern used to recognize this legacy paths so
that those with double slashes are also converted to poetry paths.

Includes 1 new unit test to cover underlying function.
Includes black formatting.

src/rockstor/scripts/initrock.py

@@ -417,7 +417,7 @@ def establish_poetry_paths():
     The local files in questions are defined in the LOCAL_FILES constant.
     """
     logger.info("### BEGIN Establishing poetry path to binaries in local files...")
-    pattern = "/opt/rockstor/bin/"
+    pattern = "/opt/rockstor[/]+bin/"
     replacement = "/opt/rockstor/.venv/bin/"
     for local_file in LOCAL_FILES:
         if os.path.isfile(LOCAL_FILES[local_file].path):

src/rockstor/system/tests/test_osi.py

@@ -14,10 +14,10 @@
 """
 import operator
 import unittest
-from unittest.mock import patch
+from unittest.mock import patch, mock_open, call
 
 from system.exceptions import CommandException
-from system.osi import get_dev_byid_name, Disk, scan_disks, get_byid_name_map, run_command
+from system.osi import get_dev_byid_name, Disk, scan_disks, get_byid_name_map, run_command, replace_pattern_inline
 
 
 class Pool(object):
@@ -2004,3 +2004,92 @@ def test_run_command(self):
             f"returned = {returned}.\n"
             f"expected = {expected}.",
         )
+
+    def test_replace_pattern_inline(self):
+        """
+        This function is only used during initrock.establish_poetry_paths() for now
+        so test using 'pattern' and 'replacement' as used during that call.
+        """
+        # Define vars
+        source_file = "/path/to/fake/source"
+        target_file = "/path/to/fake/target"
+        # Make sure `pattern` and `replacement` below match
+        # those defined in initrock.establish_poetry_paths()
+        # for this test to be meaningful
+        pattern = "/opt/rockstor[/]+bin/"
+        replacement = "/opt/rockstor/.venv/bin/"
+
+        source_contents = []
+        target_contents = []
+        outputs = []
+
+        # /etc/samba/smb.conf, True
+        source_contents.append(
+            '    root preexec = "/opt/rockstor/bin/mnt-share test_share01"'
+        )
+        target_contents.append(
+            '    root preexec = "/opt/rockstor/.venv/bin/mnt-share test_share01"'
+        )
+        outputs.append(True)
+
+        # /etc/cron.d/rockstortab, True
+        source_contents.append(
+            '42 3 * * 6 root /opt/rockstor/bin/st-system-power 1 \*-*-*-*-*-*'
+        )
+        target_contents.append(
+            '42 3 * * 6 root /opt/rockstor/.venv/bin/st-system-power 1 \*-*-*-*-*-*'
+        )
+        outputs.append(True)
+
+        # /etc/samba/smb.conf, False
+        source_contents.append(
+            '    root preexec = "/opt/rockstor/.venv/bin/mnt-share test_share01"'
+        )
+        target_contents.append(None)
+        outputs.append(False)
+
+        # /etc/cron.d/rockstortab, False
+        source_contents.append(
+            '42 3 * * 6 root /opt/rockstor/.venv/bin/st-system-power 1 \*-*-*-*-*-*'
+        )
+        target_contents.append(None)
+        outputs.append(False)
+
+        # /etc/cron.d/rockstortab, True
+        source_contents.append(
+            '42 3 * * 5 root /opt/rockstor//bin/st-pool-scrub 1 \*-*-*-*-*-*'
+        )
+        target_contents.append(
+            '42 3 * * 5 root /opt/rockstor/.venv/bin/st-pool-scrub 1 \*-*-*-*-*-*'
+        )
+        outputs.append(True)
+
+        for content, target, out in zip(source_contents, target_contents, outputs):
+            m = mock_open(read_data=content)
+            with patch("system.osi.open", m):
+                returned = replace_pattern_inline(
+                    source_file, target_file, pattern, replacement
+                )
+
+                # Test that open() was called twice
+                # (once for source_file, once for target_file)
+                self.assertEqual(m.call_count, 2)
+                calls = [
+                    call(source_file),
+                    call(target_file, "w"),
+                ]
+                m.assert_has_calls(calls, any_order=True)
+
+                if target is not None:
+                    # Write should be called
+                    m().write.assert_has_calls([call(target)])
+
+                # Test that the correct boolean is returned
+                expected = out
+                self.assertEqual(
+                    returned,
+                    expected,
+                    msg="Un-expected replace_pattern_inline() output:\n"
+                        f"returned = {returned}.\n"
+                        f"expected = {expected}.",
+                )