diff --git a/test/unit/plugins/guests/bsd/cap/virtualbox_test.rb b/test/unit/plugins/guests/bsd/cap/virtualbox_test.rb
new file mode 100644
index 000000000..6efd75437
--- /dev/null
+++ b/test/unit/plugins/guests/bsd/cap/virtualbox_test.rb
@@ -0,0 +1,225 @@
+require_relative "../../../../base"
+
+describe "VagrantPlugins::GuestBSD::Cap::VirtualBox" do
+  let(:caps) do
+    VagrantPlugins::GuestBSD::Plugin
+      .components
+      .guest_capabilities[:bsd]
+  end
+
+  let(:machine) { double("machine") }
+  let(:comm) { VagrantTests::DummyCommunicator::Communicator.new(machine) }
+  let(:mount_owner){ "vagrant" }
+  let(:mount_group){ "vagrant" }
+  let(:mount_uid){ "1000" }
+  let(:mount_gid){ "1000" }
+  let(:mount_name){ "vagrant" }
+  let(:mount_guest_path){ "/vagrant" }
+  let(:folder_options) do
+    {
+      owner: mount_owner,
+      group: mount_group,
+      hostpath: "/host/directory/path"
+    }
+  end
+  let(:cap){ caps.get(:mount_virtualbox_shared_folder) }
+
+  before do
+    allow(machine).to receive(:communicate).and_return(comm)
+  end
+
+  after do
+    comm.verify_expectations!
+  end
+
+  describe ".mount_virtualbox_shared_folder" do
+
+    before do
+      allow(comm).to receive(:sudo).with(any_args)
+      allow(comm).to receive(:execute).with(any_args)
+    end
+
+    it "generates the expected default mount command" do
+      expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+      expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{mount_gid}:")
+      expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_uid},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+      cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+    end
+
+    it "automatically chown's the mounted directory on guest" do
+      expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+      expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{mount_gid}:")
+      expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_uid},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+      expect(comm).to receive(:sudo).with("chown #{mount_uid}:#{mount_gid} #{mount_guest_path}")
+      cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+    end
+
+    context "with owner user ID explicitly defined" do
+
+      before do
+        expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{mount_gid}:")
+      end
+
+      context "with user ID provided as Integer" do
+        let(:mount_owner){ 2000 }
+
+        it "generates the expected mount command using mount_owner directly" do
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_owner},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+          expect(comm).to receive(:sudo).with("chown #{mount_owner}:#{mount_gid} #{mount_guest_path}")
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+        end
+      end
+
+      context "with user ID provided as String" do
+        let(:mount_owner){ "2000" }
+
+        it "generates the expected mount command using mount_owner directly" do
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_owner},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+          expect(comm).to receive(:sudo).with("chown #{mount_owner}:#{mount_gid} #{mount_guest_path}")
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+        end
+      end
+
+    end
+
+    context "with owner group ID explicitly defined" do
+
+      before do
+        expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+      end
+
+      context "with owner group ID provided as Integer" do
+        let(:mount_group){ 2000 }
+
+        it "generates the expected mount command using mount_group directly" do
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_uid},gid=#{mount_group} #{mount_name} #{mount_guest_path}", anything)
+          expect(comm).to receive(:sudo).with("chown #{mount_uid}:#{mount_group} #{mount_guest_path}")
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+        end
+      end
+
+      context "with owner group ID provided as String" do
+        let(:mount_group){ "2000" }
+
+        it "generates the expected mount command using mount_group directly" do
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_uid},gid=#{mount_group} #{mount_name} #{mount_guest_path}", anything)
+          expect(comm).to receive(:sudo).with("chown #{mount_uid}:#{mount_group} #{mount_guest_path}")
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+        end
+      end
+
+    end
+
+    context "with non-existent default owner group" do
+
+      it "fetches the effective group ID of the user" do
+        expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+        expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_raise(Vagrant::Errors::VirtualBoxMountFailed, {command: '', output: ''})
+        expect(comm).to receive(:execute).with("id -g #{mount_owner}", anything).and_yield(:stdout, "1").and_return(0)
+        cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+      end
+    end
+
+    context "with non-existent owner group" do
+
+      it "raises an error" do
+        expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+        expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_raise(Vagrant::Errors::VirtualBoxMountFailed, {command: '', output: ''})
+        expect do
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+        end.to raise_error Vagrant::Errors::VirtualBoxMountFailed
+      end
+    end
+
+    context "with read-only option defined" do
+
+      it "does not chown mounted guest directory" do
+        expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+        expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{mount_gid}:")
+        expect(comm).to receive(:sudo).with("mount -t vboxvfs -o ro,uid=#{mount_uid},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+        expect(comm).not_to receive(:sudo).with("chown #{mount_uid}:#{mount_gid} #{mount_guest_path}")
+        cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options.merge(mount_options: ["ro"]))
+      end
+    end
+
+    context "with upstart init" do
+
+      it "emits mount event" do
+        expect(comm).to receive(:sudo).with(/initctl emit/)
+        cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+      end
+    end
+
+    context "with custom mount options" do
+
+      let(:ui){ double(:ui) }
+      before do
+        allow(ui).to receive(:warn)
+        allow(machine).to receive(:ui).and_return(ui)
+      end
+
+      context "with uid defined" do
+        let(:options_uid){ '1234' }
+
+        it "should only include uid defined within mount options" do
+          expect(comm).not_to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+          expect(comm).to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{mount_gid}:")
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{options_uid},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options.merge(mount_options: ["uid=#{options_uid}"]))
+        end
+      end
+
+      context "with gid defined" do
+        let(:options_gid){ '1234' }
+
+        it "should only include gid defined within mount options" do
+          expect(comm).to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+          expect(comm).not_to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{mount_gid}:")
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{mount_uid},gid=#{options_gid} #{mount_name} #{mount_guest_path}", anything)
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options.merge(mount_options: ["gid=#{options_gid}"]))
+        end
+      end
+
+      context "with uid and gid defined" do
+        let(:options_gid){ '1234' }
+        let(:options_uid){ '1234' }
+
+        it "should only include uid and gid defined within mount options" do
+          expect(comm).not_to receive(:execute).with("id -u #{mount_owner}", anything).and_yield(:stdout, mount_uid)
+          expect(comm).not_to receive(:execute).with("getent group #{mount_group}", anything).and_yield(:stdout, "vagrant:x:#{options_gid}:")
+          expect(comm).to receive(:sudo).with("mount -t vboxvfs -o uid=#{options_uid},gid=#{options_gid} #{mount_name} #{mount_guest_path}", anything)
+          cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options.merge(mount_options: ["gid=#{options_gid}", "uid=#{options_uid}"]))
+        end
+      end
+    end
+
+    context "with guest builtin vboxvfs module" do
+      let(:vbox_stderr){ <<-EOF
+mount.vboxvfs cannot be used with mainline vboxvfs; instead use:
+
+    mount -cit vboxvfs NAME MOUNTPOINT
+EOF
+      }
+      it "should perform guest mount using builtin module" do
+        expect(comm).to receive(:sudo).with(/mount -t vboxvfs/, any_args).and_yield(:stderr, vbox_stderr).and_return(1)
+        expect(comm).to receive(:sudo).with(/mount -cit/, any_args)
+        cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
+      end
+    end
+  end
+
+  describe ".unmount_virtualbox_shared_folder" do
+
+    after { cap.unmount_virtualbox_shared_folder(machine, mount_guest_path, folder_options) }
+
+    it "unmounts shared directory and deletes directory on guest" do
+      expect(comm).to receive(:sudo).with("umount #{mount_guest_path}", anything).and_return(0)
+      expect(comm).to receive(:sudo).with("rmdir #{mount_guest_path}", anything)
+    end
+
+    it "does not delete guest directory if unmount fails" do
+      expect(comm).to receive(:sudo).with("umount #{mount_guest_path}", anything).and_return(1)
+      expect(comm).not_to receive(:sudo).with("rmdir #{mount_guest_path}", anything)
+    end
+  end
+end