provisioners/salt: error if minion_config missing

plugins/provisioners/salt/config.rb

@@ -90,6 +90,13 @@ module VagrantPlugins
           end
         end
 
+        if @master_config
+          expanded = Pathname.new(@master_config).expand_path(machine.env.root_path)
+          if !expanded.file?
+            errors << I18n.t("vagrant.provisioners.salt.master_config_nonexist")
+          end
+        end
+
         if @minion_key || @minion_pub
           if !@minion_key || !@minion_pub
             errors << I18n.t("vagrant.provisioners.salt.missing_key")

templates/locales/en.yml

@@ -1635,6 +1635,8 @@ en:
       salt:
         minion_config_nonexist: |-
           The specified minion_config file could not be found.
+        master_config_nonexist: |-
+          The specified master_config file could not be found.
         missing_key: |-
           You must include both public and private keys.
         must_accept_keys: |-

test/unit/plugins/provisioners/salt/config_test.rb

@@ -42,5 +42,23 @@ describe VagrantPlugins::Salt::Config do
         expect(result[error_key]).to be_empty
       end
     end
+
+    context "master_config" do
+      it "fails if master_config is set and missing" do
+        subject.master_config = "/ceci/nest/pas/une/path"
+        subject.finalize!
+
+        result = subject.validate(machine)
+        expect(result[error_key]).to_not be_empty
+      end
+
+      it "is valid if is set and not missing" do
+        subject.master_config = File.expand_path(__FILE__)
+        subject.finalize!
+
+        result = subject.validate(machine)
+        expect(result[error_key]).to be_empty
+      end
+    end
   end
 end