Merge lp:~thedac/charm-helpers/bug1601972 into lp:charm-helpers

[David Ames]

Make apt_install fatal=True for dnspython install

The ns_query code was installing python-dnspython without fatal=True.
The charm would assume it was installed and then fail hard when that module
was not available. Make the apt_install fatal=True

Fixes LP#1601972

[Liam Young (gnuoy)]

LGTM, thanks

review: Approve

=== modified file 'charmhelpers/contrib/network/ip.py'
--- charmhelpers/contrib/network/ip.py	2016-07-06 14:41:05 +0000
+++ charmhelpers/contrib/network/ip.py	2016-07-18 16:04:26 +0000
@@ -414,7 +414,7 @@
     try:
         import dns.resolver
     except ImportError:
-        apt_install('python-dnspython')
+        apt_install('python-dnspython', fatal=True)
         import dns.resolver
 
     if isinstance(address, dns.name.Name):
@@ -458,7 +458,7 @@
         try:
             import dns.reversename
         except ImportError:
-            apt_install("python-dnspython")
+            apt_install("python-dnspython", fatal=True)
             import dns.reversename
 
         rev = dns.reversename.from_address(address)
 
=== modified file 'tests/contrib/network/test_ip.py'
--- tests/contrib/network/test_ip.py	2016-05-27 09:20:25 +0000
+++ tests/contrib/network/test_ip.py	2016-07-18 16:04:26 +0000
@@ -641,7 +641,7 @@
         fake_dns = FakeDNS('5.5.5.5')
         with patch(builtin_import, side_effect=[ImportError, fake_dns]):
             nsq = net_ip.ns_query('5.5.5.5')
-            apt_install.assert_called_with('python-dnspython')
+            apt_install.assert_called_with('python-dnspython', fatal=True)
         self.assertEquals(nsq, '5.5.5.5')
 
     @patch('charmhelpers.contrib.network.ip.apt_install')
@@ -708,7 +708,7 @@
         with patch(builtin_import, side_effect=[ImportError, fake_dns,
                                                 fake_dns]):
             hn = net_ip.get_hostname('4.2.2.1')
-            apt_install.assert_called_with('python-dnspython')
+            apt_install.assert_called_with('python-dnspython', fatal=True)
         self.assertEquals(hn, 'www.ubuntu.com')
 
     @patch('charmhelpers.contrib.network.ip.socket.gethostbyaddr')