Merge lp:~cjwatson/launchpad-buildd/is-package-available-virtual into lp:launchpad-buildd

[Colin Watson]

Make Backend.is_package_available handle the case where the requested
package name is purely virtual.

[lp:~cjwatson/launchpad-buildd/is-package-available-virtual]

303. By Colin Watson on 2017-11-01

Don't assume that Package: is the first line.

[William Grant (wgrant)]

review: Approve (code)

=== modified file 'debian/changelog'
--- debian/changelog	2017-11-01 11:17:44 +0000
+++ debian/changelog	2017-11-01 23:08:33 +0000
@@ -12,6 +12,8 @@
   * Raise more useful exceptions when LXD.copy_in or LXD.copy_out fail.
   * Make Backend.run implementations print command output if echo and
     get_output are both true.
+  * Make Backend.is_package_available handle the case where the requested
+    package name is purely virtual.
 
  -- Colin Watson <[e-mail]>  Fri, 08 Sep 2017 13:42:17 +0100
 
 
=== modified file 'lpbuildd/target/backend.py'
--- lpbuildd/target/backend.py	2017-11-01 11:17:44 +0000
+++ lpbuildd/target/backend.py	2017-11-01 23:08:33 +0000
@@ -152,10 +152,10 @@
         """
         try:
             with open("/dev/null", "w") as devnull:
-                self.run(
+                output = self.run(
                     ["apt-cache", "show", package],
-                    stdout=devnull, stderr=devnull)
-            return True
+                    get_output=True, stderr=devnull)
+            return ("Package: %s" % package) in output.splitlines()
         except subprocess.CalledProcessError:
             return False
 
 
=== modified file 'lpbuildd/target/tests/test_chroot.py'
--- lpbuildd/target/tests/test_chroot.py	2017-09-08 15:57:18 +0000
+++ lpbuildd/target/tests/test_chroot.py	2017-11-01 23:08:33 +0000
@@ -271,18 +271,24 @@
     def test_is_package_available(self):
         self.useFixture(EnvironmentVariable("HOME", "/expected/home"))
         processes_fixture = self.useFixture(FakeProcesses())
-        test_proc_infos = iter([{}, {"returncode": 100}])
+        test_proc_infos = iter([
+            {"stdout": io.BytesIO(b"Package: snapd\n")},
+            {"returncode": 100},
+            {"stderr": io.BytesIO(b"N: No packages found\n")},
+            ])
         processes_fixture.add(lambda _: next(test_proc_infos), name="sudo")
         self.assertTrue(
             Chroot("1", "xenial", "amd64").is_package_available("snapd"))
         self.assertFalse(
             Chroot("1", "xenial", "amd64").is_package_available("nonexistent"))
+        self.assertFalse(
+            Chroot("1", "xenial", "amd64").is_package_available("virtual"))
 
         expected_args = [
             ["sudo", "/usr/sbin/chroot",
              "/expected/home/build-1/chroot-autobuild",
              "linux64", "apt-cache", "show", package]
-            for package in ("snapd", "nonexistent")
+            for package in ("snapd", "nonexistent", "virtual")
             ]
         self.assertEqual(
             expected_args,
 
=== modified file 'lpbuildd/target/tests/test_lxd.py'
--- lpbuildd/target/tests/test_lxd.py	2017-11-01 11:13:36 +0000
+++ lpbuildd/target/tests/test_lxd.py	2017-11-01 23:08:33 +0000
@@ -593,17 +593,23 @@
 
     def test_is_package_available(self):
         processes_fixture = self.useFixture(FakeProcesses())
-        test_proc_infos = iter([{}, {"returncode": 100}])
+        test_proc_infos = iter([
+            {"stdout": io.BytesIO(b"Package: snapd\n")},
+            {"returncode": 100},
+            {"stderr": io.BytesIO(b"N: No packages found\n")},
+            ])
         processes_fixture.add(lambda _: next(test_proc_infos), name="lxc")
         self.assertTrue(
             LXD("1", "xenial", "amd64").is_package_available("snapd"))
         self.assertFalse(
             LXD("1", "xenial", "amd64").is_package_available("nonexistent"))
+        self.assertFalse(
+            LXD("1", "xenial", "amd64").is_package_available("virtual"))
 
         expected_args = [
             ["lxc", "exec", "lp-xenial-amd64", "--",
              "linux64", "apt-cache", "show", package]
-            for package in ("snapd", "nonexistent")
+            for package in ("snapd", "nonexistent", "virtual")
             ]
         self.assertEqual(
             expected_args,