Adding pip_install_cmd as a default parameter to get_pip. Unit Tests.

plugins/provisioners/ansible/cap/guest/pip/pip.rb

@@ -18,9 +18,9 @@ module VagrantPlugins
             machine.communicate.sudo "pip install #{args_array.join(' ')}"
           end
 
-          def self.get_pip(machine)
+          def self.get_pip(machine, pip_install_cmd="curl https://bootstrap.pypa.io/get-pip.py | sudo python")
             machine.ui.detail I18n.t("vagrant.provisioners.ansible.installing_pip")
-            machine.communicate.execute "curl https://bootstrap.pypa.io/get-pip.py | sudo python"
+            machine.communicate.execute pip_install_cmd
           end
 
         end

test/unit/plugins/provisioners/ansible/cap/guest/pip/pip_test.rb

@@ -0,0 +1,41 @@
+require_relative "../../../../../../base"
+
+require Vagrant.source_root.join("plugins/provisioners/ansible/cap/guest/pip/pip")
+
+describe VagrantPlugins::Ansible::Cap::Guest::Pip do
+  include_context "unit"
+
+  subject { VagrantPlugins::Ansible::Cap::Guest::Pip }
+
+  let(:iso_env) do
+    # We have to create a Vagrantfile so there is a root path
+    env = isolated_environment
+    env.vagrantfile("")
+    env.create_vagrant_env
+  end
+
+  let(:machine) { iso_env.machine(iso_env.machine_names[0], :dummy) }
+  let(:communicator) { double("comm") }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(communicator)
+    allow(communicator).to receive(:execute).and_return(true)
+  end
+
+  describe "#get_pip" do
+    describe 'when no pip_install_command argument is provided' do
+        it "installs pip using the default command" do
+            expect(communicator).to receive(:execute).with("curl https://bootstrap.pypa.io/get-pip.py | sudo python")
+            subject.get_pip(machine)
+        end
+    end
+
+    describe 'when pip_install_command argument is provided' do
+        it "runs the supplied argument instead of default" do
+            pip_install_command = "foo"
+            expect(communicator).to receive(:execute).with(pip_install_command)
+            subject.get_pip(machine,pip_install_command)
+        end
+    end    
+  end
+end