Prevent other provider install attempts when explicit provider given

plugins/commands/up/command.rb

@@ -128,7 +128,7 @@ module VagrantPlugins
         # First create a set of all the providers we need to check for.
         # Most likely this will be a set of one.
         providers = Set.new
-        with_target_vms(names) do |machine|
+        with_target_vms(names, provider: provider) do |machine|
           # Check if we have this machine in the index
           entry    = @env.machine_index.get(machine.name.to_s)
 

test/unit/plugins/commands/up/command_test.rb

@@ -0,0 +1,65 @@
+require File.expand_path("../../../../base", __FILE__)
+
+require Vagrant.source_root.join("plugins/commands/up/command")
+
+describe VagrantPlugins::CommandUp::Command do
+  include_context "unit"
+
+  let(:argv)     { [] }
+  let(:vagrantfile_content){ "" }
+  let(:iso_env) do
+    env = isolated_environment
+    env.vagrantfile(vagrantfile_content)
+    env.create_vagrant_env
+  end
+
+  subject { described_class.new(argv, iso_env) }
+
+  let(:action_runner) { double("action_runner") }
+
+  before do
+    iso_env.stub(action_runner: action_runner)
+  end
+
+  context "with no argument" do
+    let(:vagrantfile_content){ "Vagrant.configure(2){|config| config.vm.box = 'dummy'}" }
+
+    it "should bring up the default box" do
+      batch = double("environment_batch")
+      expect(iso_env).to receive(:batch).and_yield(batch)
+      expect(batch).to receive(:action).with(anything, :up, anything)
+      subject.execute
+    end
+
+    context "with VAGRANT_DEFAULT_PROVIDER set" do
+      before do
+        if ENV["VAGRANT_DEFAULT_PROVIDER"]
+          @original_default = ENV["VAGRANT_DEFAULT_PROVIDER"]
+        end
+        ENV["VAGRANT_DEFAULT_PROVIDER"] = "unknown"
+      end
+      after do
+        if @original_default
+          ENV["VAGRANT_DEFAULT_PROVIDER"] = @original_default
+        else
+          ENV.delete("VAGRANT_DEFAULT_PROVIDER")
+        end
+      end
+
+      it "should attempt to use dummy provider" do
+        expect{ subject.execute }.to raise_error
+      end
+
+      context "with --provider set" do
+        let(:argv){ ["--provider", "dummy"] }
+
+        it "should only use provider explicitly set" do
+          batch = double("environment_batch")
+          expect(iso_env).to receive(:batch).and_yield(batch)
+          expect(batch).to receive(:action).with(anything, :up, anything)
+          subject.execute
+        end
+      end
+    end
+  end
+end