Supports debian_version file content for version(best=True) calls

src/distro/distro.py

@@ -898,6 +898,15 @@ def version(self, pretty: bool = False, best: bool = False) -> str:
         if self.uname_attr("id").startswith("aix"):
             # On AIX platforms, prefer oslevel command output.
             versions.insert(0, self.oslevel_info())
+        elif self.id() == "debian" or "debian" in self.like().split():
+            # On Debian-like, add debian_version file content to candidates list.
+            try:
+                with open(
+                    os.path.join(self.etc_dir, "debian_version"), encoding="ascii"
+                ) as fp:
+                    versions.append(fp.readline().rstrip())
+            except FileNotFoundError:
+                pass
         version = ""
         if best:
             # This algorithm uses the last version in priority order that has

tests/resources/distros/debian10/bin/lsb_release

@@ -0,0 +1,21 @@
+#!/bin/bash
+#
+# lsb_release command for testing the ld module.
+# Only the -a option is supported.
+#
+# This version of the lsb_release command works without a corresponding
+# etc/lsb-release file.
+#
+
+if [[ "$@" != "-a" ]]; then
+  echo "Usage: lsb_release -a"
+  exit 2
+fi
+
+echo "No LSB modules are available."
+echo "Distributor ID:	Debian"
+echo "Description:	Debian GNU/Linux 10 (buster)"
+echo "Release:	10"
+echo "Codename:	buster"
+
+exit 0

tests/resources/distros/debian10/etc/debian_version

@@ -0,0 +1 @@
+10.11

tests/resources/distros/debian10/etc/os-release

@@ -0,0 +1,9 @@
+PRETTY_NAME="Debian GNU/Linux 10 (buster)"
+NAME="Debian GNU/Linux"
+VERSION_ID="10"
+VERSION="10 (buster)"
+VERSION_CODENAME=buster
+ID=debian
+HOME_URL="https://www.debian.org/"
+SUPPORT_URL="https://www.debian.org/support"
+BUG_REPORT_URL="https://bugs.debian.org/"

tests/test_distro.py

@@ -138,11 +138,10 @@ def _setup_for_distro(self, distro_root: str) -> None:
 class TestOSRelease:
     def setup_method(self, test_method: FunctionType) -> None:
         dist = test_method.__name__.split("_")[1]
-        os_release = os.path.join(DISTROS_DIR, dist, "etc", "os-release")
         self.distro = distro.LinuxDistribution(
             include_lsb=False,
-            os_release_file=os_release,
             distro_release_file="path-to-non-existing-file",
+            root_dir=os.path.join(DISTROS_DIR, dist),
         )
 
     def _test_outcome(self, outcome: Dict[str, str]) -> None:
@@ -217,11 +216,23 @@ def test_debian8_os_release(self) -> None:
             "pretty_name": "Debian GNU/Linux 8 (jessie)",
             "version": "8",
             "pretty_version": "8 (jessie)",
-            "best_version": "8",
+            "best_version": "8.2",
             "codename": "jessie",
         }
         self._test_outcome(desired_outcome)
 
+    def test_debian10_os_release(self) -> None:
+        desired_outcome = {
+            "id": "debian",
+            "name": "Debian GNU/Linux",
+            "pretty_name": "Debian GNU/Linux 10 (buster)",
+            "version": "10",
+            "pretty_version": "10 (buster)",
+            "best_version": "10.11",
+            "codename": "buster",
+        }
+        self._test_outcome(desired_outcome)
+
     def test_fedora19_os_release(self) -> None:
         desired_outcome = {
             "id": "fedora",
@@ -346,7 +357,7 @@ def test_raspbian7_os_release(self) -> None:
             "pretty_name": "Raspbian GNU/Linux 7 (wheezy)",
             "version": "7",
             "pretty_version": "7 (wheezy)",
-            "best_version": "7",
+            "best_version": "7.1",
             "like": "debian",
             "codename": "wheezy",
         }
@@ -359,7 +370,7 @@ def test_raspbian8_os_release(self) -> None:
             "pretty_name": "Raspbian GNU/Linux 8 (jessie)",
             "version": "8",
             "pretty_version": "8 (jessie)",
-            "best_version": "8",
+            "best_version": "8.0",
             "like": "debian",
             "codename": "jessie",
         }
@@ -1230,6 +1241,20 @@ def test_debian8_release(self) -> None:
         self._test_outcome(desired_outcome)
         self._test_non_existing_release_file()
 
+    def test_debian10_release(self) -> None:
+        desired_outcome = {
+            "id": "debian",
+            "name": "Debian GNU/Linux",
+            "pretty_name": "Debian GNU/Linux 10 (buster)",
+            "version": "10",
+            "pretty_version": "10 (buster)",
+            "best_version": "10.11",
+            "codename": "buster",
+            "major_version": "10",
+        }
+        self._test_outcome(desired_outcome)
+        self._test_non_existing_release_file()
+
     def test_exherbo_release(self) -> None:
         desired_outcome = {
             "id": "exherbo",
@@ -1448,7 +1473,7 @@ def test_raspbian7_release(self) -> None:
             "pretty_name": "Raspbian GNU/Linux 7 (wheezy)",
             "version": "7",
             "pretty_version": "7 (wheezy)",
-            "best_version": "7",
+            "best_version": "7.1",
             "like": "debian",
             "codename": "wheezy",
             "major_version": "7",
@@ -1463,7 +1488,7 @@ def test_raspbian8_release(self) -> None:
             "pretty_name": "Raspbian GNU/Linux 8 (jessie)",
             "version": "8",
             "pretty_version": "8 (jessie)",
-            "best_version": "8",
+            "best_version": "8.0",
             "like": "debian",
             "codename": "jessie",
             "major_version": "8",