Add testing for Debian testing and unstable

Since the testing and unstable suites don't have version numbers
(similar to some other rolling release distros), but we have some
Debian-specific logic in the program, we need to make sure future
changes don't regress this platform.

Change-Id: I8eac47772b2ec277e0868798846683818149061f

bindep/tests/fixtures/debiansid/etc/os-release

@@ -0,0 +1,7 @@
+PRETTY_NAME="Debian GNU/Linux xyzzy/sid"
+NAME="Debian GNU/Linux"
+VERSION_CODENAME=xyzzy
+ID=debian
+HOME_URL="https://www.debian.org/"
+SUPPORT_URL="https://www.debian.org/support"
+BUG_REPORT_URL="https://bugs.debian.org/"

bindep/tests/test_depends.py

@@ -266,6 +266,15 @@ class TestDepends(TestCase):
             self.assertThat(
                 depends.platform_profiles(), Contains("platform:rpm"))
 
+    def test_detects_debian_sid(self):
+        with DistroFixture("DebianSid"):
+            depends = Depends("")
+            self.assertThat(
+                depends.platform_profiles(), Contains("platform:debian"))
+            self.assertThat(
+                depends.platform_profiles(),
+                Contains("platform:debian-xyzzy"))
+
     def test_detects_release(self):
         with DistroFixture("Ubuntu"):
             depends = Depends("")