create Prefile class

scripts/snap_pac.py

@@ -135,17 +135,27 @@ def get_snapper_configs(conf_file):
             return line[1].lstrip("\"").split()
 
 
-def get_pre_number(snapshot_type, prefile):
-    if snapshot_type == "pre":
-        pre_number = None
-    else:
-        try:
-            pre_number = prefile.read_text()
-        except FileNotFoundError:
-            raise FileNotFoundError(f"prefile {prefile} not found. Ensure you have run the pre snapshot first.")
+class Prefile:
+    """Handles reading and writing of pre snapshot number."""
+    def __init__(self, snapper_config, snapshot_type):
+        self.file = Path(tempfile.gettempdir()) / f"snap-pac-pre_{snapper_config}"
+        self.snapshot_type = snapshot_type
+
+    def read(self):
+        if self.snapshot_type == "pre":
+            pre_number = None
         else:
-            prefile.unlink()
-    return pre_number
+            try:
+                pre_number = self.file.read_text()
+            except FileNotFoundError:
+                raise FileNotFoundError(f"prefile {self.file} not found. Ensure you have run the pre snapshot first.")
+            else:
+                self.file.unlink()
+        return pre_number
+
+    def write(self, num):
+        if self.snapshot_type == "pre":
+            self.file.write_text(num)
 
 
 def check_skip():
@@ -177,18 +187,15 @@ if __name__ == "__main__":
     config_processor = ConfigProcessor(snap_pac_ini, snapshot_type)
     snapper_configs = get_snapper_configs(snapper_conf_file)
     chroot = os.stat("/") != os.stat("/proc/1/root/.")
-    tmpdir = Path(tempfile.gettempdir())
 
     for snapper_config in snapper_configs:
 
         data = config_processor(snapper_config)
         if data["snapshot"]:
-            prefile = tmpdir / f"snap-pac-pre_{snapper_config}"
-            pre_number = get_pre_number(snapshot_type, prefile)
+            prefile = Prefile(snapper_config, snapshot_type)
+            pre_number = prefile.read()
             snapper_cmd = SnapperCmd(snapper_config, snapshot_type, data["cleanup_algorithm"],
                                      data["description"], chroot, pre_number, data["userdata"])
             num = snapper_cmd()
             logging.info(f"==> {snapper_config}: {num}")
-
-            if snapshot_type == "pre":
-                prefile.write_text(num)
+            prefile.write(num)

tests/test_script.py

@@ -4,15 +4,7 @@ import os
 
 import pytest
 
-from scripts.snap_pac import SnapperCmd, ConfigProcessor, check_skip, get_pre_number, get_snapper_configs
-
-
-@pytest.fixture
-def prefile():
-    with tempfile.NamedTemporaryFile("w", delete=False) as f:
-        f.write("1234")
-        name = f.name
-    return Path(name)
+from scripts.snap_pac import check_skip, ConfigProcessor, get_snapper_configs, Prefile, SnapperCmd
 
 
 @pytest.mark.parametrize("snapper_cmd, actual_cmd", [
@@ -108,14 +100,19 @@ def test_config_processor(section, command, packages, snapshot_type, result):
     assert config_processor(section) == result
 
 
-def test_get_pre_number_pre(prefile):
-    assert get_pre_number("pre", prefile) is None
+def test_prefile_read_none():
+    prefile = Prefile("root", "pre")
+    assert prefile.read() is None
 
 
-def test_get_pre_number_post(prefile):
-    assert get_pre_number("post", prefile) == "1234"
+def test_prefile_read():
+    prefile = Prefile("root", "pre")
+    prefile.write("1234")
+    prefile = Prefile("root", "post")
+    assert prefile.read() == "1234"
 
 
 def test_no_prefile():
+    prefile = Prefile("foo-pre-file-not-found", "post")
     with pytest.raises(FileNotFoundError):
-        get_pre_number("post", Path("/tmp/foo-pre-file-not-found"))
+        prefile.read()