Add test for config_get dracut function

This commit will also add code to enable testing of the Dracut shell
scripts.

Related: RHEL-48821

tests/unit_tests/dracut_tests/test_dracut_anaconda-lib.py

@@ -0,0 +1,167 @@
+#
+# Copyright 2025 Red Hat, Inc.
+#
+# This copyrighted material is made available to anyone wishing to use, modify,
+# copy, or redistribute it subject to the terms and conditions of the GNU
+# General Public License v.2.  This program is distributed in the hope that it
+# will be useful, but WITHOUT ANY WARRANTY expressed or implied, including the
+# implied warranties of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc., 51
+# Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  Any Red Hat
+# trademarks that are incorporated in the source code or documentation are not
+# subject to the GNU General Public License and may only be used or replicated
+# with the express permission of Red Hat, Inc.
+
+import unittest
+import os
+import subprocess
+import re
+
+from tempfile import NamedTemporaryFile, TemporaryDirectory
+from collections import namedtuple
+
+
+DISABLE_COMMANDS = [
+    "command",
+]
+DISABLE_COMMAND_PREFIX = "disabled-command"
+
+
+SubprocessReturn = namedtuple("SubprocessReturn",
+                              ["returncode", "disabled_cmd_args", "stdout","stderr"])
+
+
+class AnacondaLibTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self._temp_dir = TemporaryDirectory()
+        self._content = ""
+
+        fake_command = os.path.join(self._temp_dir.name, "command")
+
+        with open(fake_command, "wt", encoding="utf-8") as f:
+            f.write("exit 0")
+
+        os.chmod(fake_command, 0o755)
+
+    def tearDown(self):
+        self._temp_dir.cleanup()
+
+    def _load_script(self, script_name):
+        with open(os.path.join("../dracut/", script_name), "rt", encoding="utf-8") as f:
+            self._content = f.read()
+
+        disable_list = []
+        # disable external and problematic commands in Dracut
+        for disabled_cmd in DISABLE_COMMANDS:
+            disable_list.append(f"""
+{disabled_cmd}() {{
+    echo "{DISABLE_COMMAND_PREFIX}: {disabled_cmd} args: $@" >&2
+}}
+""")
+
+        lines = self._content.splitlines()
+        self._content = lines[0] + "\n" + "\n".join(disable_list) + "\n" + "\n".join(lines[1:])
+
+        #self._content = self._content.replace("command -v", "# command -v", count=3)
+
+    def _run_shell_command(self, command):
+        """Run a shell command and return the output
+
+        This function will also split out disabled commands args from the stdout and returns
+        it as named tuple.
+
+        :returns: SubprocessReturn named tuple
+        """
+        command = f"{self._content}\n\n{command}"
+        print(command)
+        ret = subprocess.run(
+            ["bash", "-c", command],
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            encoding="utf-8",
+            check=False,
+        )
+
+        disabled_cmd_args, stderr = self._separate_disabled_commands_msgs(ret.stderr)
+
+        return SubprocessReturn(
+            returncode=ret.returncode,
+            disabled_cmd_args=disabled_cmd_args,
+            stdout=ret.stdout.strip(),
+            stderr=stderr
+        )
+
+    def _separate_disabled_commands_msgs(self, stderr):
+        stderr_final = ""
+        disabled_cmd_args = {}
+        for line in stderr.splitlines():
+            if line.startswith(DISABLE_COMMAND_PREFIX):
+                print(line)
+                match = re.search(fr"{DISABLE_COMMAND_PREFIX}: ([\w-]+) args: (.*)$", line)
+                print(match)
+                if match.group(1) in disabled_cmd_args:
+                    disabled_cmd_args[match.group(1)].append(match.group(2))
+                else:
+                    disabled_cmd_args[match.group(1)] = [match.group(2)]
+                continue
+
+            stderr_final += line + "\n"
+
+        return disabled_cmd_args, stderr_final
+
+    def _check_get_text_with_content(self, test_input, expected_stdout):
+        with NamedTemporaryFile(mode="wt", delete_on_close=False) as test_file:
+            test_file.write(test_input)
+            test_file.close()
+            ret = self._run_shell_command(f"config_get tree arch < {test_file.name}")
+            assert ret.returncode == 0
+            assert ret.stdout == expected_stdout
+
+    def test_config_get(self):
+        """Test bash config_get function to read .treeinfo file"""
+        self._load_script("anaconda-lib.sh")
+
+        # test multiple values in file
+        self._check_get_text_with_content("""
+[tree]
+arch=x86_64
+[config]
+abc=cde
+""",
+        "x86_64")
+
+        # test space before and after '='
+        self._check_get_text_with_content("""
+[tree]
+arch = aarch64
+[config]
+abc=cde
+""",
+        "aarch64")
+
+        # test multiple spaces before and after '='
+        self._check_get_text_with_content("""
+[tree]
+arch   =        ppc64
+[config]
+abc=cde
+""",
+        "ppc64")
+
+        # test indented section
+        self._check_get_text_with_content("""
+    [tree]
+    arch = ppc64le
+""",
+        "ppc64le")
+
+        # test indented value in section
+        self._check_get_text_with_content("""
+    [tree]
+        arch = s390
+""",
+        "s390")