guests/suse: Change host name in one command

plugins/guests/suse/cap/change_host_name.rb

@@ -3,14 +3,22 @@ module VagrantPlugins
     module Cap
       class ChangeHostName
         def self.change_host_name(machine, name)
-          machine.communicate.tap do |comm|
+          comm = machine.communicate
-            # Only do this if the hostname is not already set
-            if !comm.test("sudo hostname | grep '#{name}'")
-              comm.sudo("echo #{name} > /etc/HOSTNAME")
-              comm.sudo("hostname #{name}")
 
-              comm.sudo("sed -i 's@^\\(127[.]0[.]0[.]1[[:space:]]\\+\\)@\\1#{name} #{name.split('.')[0]} @' /etc/hosts")
+          if !comm.test("hostname -f | grep -w '#{name}'", sudo: false)
-            end
+            basename = name.split(".", 2)[0]
+            comm.sudo <<-EOH.gsub(/^ {14}/, '')
+              echo '#{name}' > /etc/HOSTNAME
+              hostname '#{name}'
+
+              # Remove comments and blank lines from /etc/hosts
+              sed -i'' -e 's/#.*$//' -e '/^$/d' /etc/hosts
+
+              # Prepend ourselves to /etc/hosts
+              grep -w '#{name}' /etc/hosts || {
+                sed -i'' '1i 127.0.0.1\\t#{name}\\t#{basename}' /etc/hosts
+              }
+            EOH
           end
         end
       end

test/unit/plugins/guests/suse/cap/change_host_name_test.rb

@@ -0,0 +1,40 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestSUSE::Cap::ChangeHostName" do
+  let(:caps) do
+    VagrantPlugins::GuestSUSE::Plugin
+      .components
+      .guest_capabilities[:suse]
+  end
+
+  let(:machine) { double("machine") }
+  let(:comm) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(comm)
+  end
+
+  after do
+    comm.verify_expectations!
+  end
+
+  describe ".change_host_name" do
+    let(:cap) { caps.get(:change_host_name) }
+
+    let(:name) { "banana-rama.example.com" }
+
+    it "sets the hostname" do
+      comm.stub_command("hostname -f | grep -w '#{name}'", exit_code: 1)
+
+      cap.change_host_name(machine, name)
+      expect(comm.received_commands[1]).to match(/echo '#{name}' > \/etc\/HOSTNAME/)
+      expect(comm.received_commands[1]).to match(/hostname '#{name}'/)
+    end
+
+    it "does not change the hostname if already set" do
+      comm.stub_command("hostname -f | grep -w '#{name}'", exit_code: 0)
+      cap.change_host_name(machine, name)
+      expect(comm.received_commands.size).to eq(1)
+    end
+  end
+end