diff --git a/app/models/command/go_to_card.rb b/app/models/command/go_to_card.rb
index 06508c129..0943413f3 100644
--- a/app/models/command/go_to_card.rb
+++ b/app/models/command/go_to_card.rb
@@ -1,7 +1,7 @@
 class Command::GoToCard < Command
   store_accessor :data, :card_id
 
-  validates_presence_of :card_id
+  validates_presence_of :card
 
   def title
     "Visit card '#{card.title}'"
diff --git a/app/models/command/go_to_user.rb b/app/models/command/go_to_user.rb
index 763a3f351..ffb275f53 100644
--- a/app/models/command/go_to_user.rb
+++ b/app/models/command/go_to_user.rb
@@ -1,7 +1,7 @@
 class Command::GoToUser < Command
   store_accessor :data, :user_id
 
-  validates_presence_of :user_id
+  validates_presence_of :user
 
   def title
     "View profile of '#{user.name}'"
@@ -13,6 +13,6 @@ class Command::GoToUser < Command
 
   private
     def user
-      User.find(user_id)
+      User.find_by_id(user_id)
     end
 end
diff --git a/app/models/command/parser/context.rb b/app/models/command/parser/context.rb
index 315c155a6..c4c0721c2 100644
--- a/app/models/command/parser/context.rb
+++ b/app/models/command/parser/context.rb
@@ -22,7 +22,7 @@ class Command::Parser::Context
     attr_reader :controller, :action, :params
 
     def extract_url_components(url)
-      uri = URI.parse(url)
+      uri = URI.parse(url || "")
       route = Rails.application.routes.recognize_path(uri.path)
       @controller = route[:controller]
       @action = route[:action]
diff --git a/test/models/command/go_to_card_test.rb b/test/models/command/go_to_card_test.rb
new file mode 100644
index 000000000..6078bb298
--- /dev/null
+++ b/test/models/command/go_to_card_test.rb
@@ -0,0 +1,23 @@
+require "test_helper"
+
+class Command::GoToCardTest < ActionDispatch::IntegrationTest
+  include CommandTestHelper
+
+  setup do
+    @card = cards(:logo)
+  end
+
+  test "redirects to the card perma" do
+    result = execute_command "#{@card.id}"
+
+    assert_equal @card, result.url
+  end
+
+  test "results in a regular search if the card does not exist" do
+    command = parse_command "123"
+    assert command.valid?
+
+    result = command.execute
+    assert_equal cards_path(indexed_by: "newest", terms: [ "123" ]), result.url
+  end
+end
diff --git a/test/models/command/go_to_user_test.rb b/test/models/command/go_to_user_test.rb
new file mode 100644
index 000000000..bb11648f5
--- /dev/null
+++ b/test/models/command/go_to_user_test.rb
@@ -0,0 +1,16 @@
+require "test_helper"
+
+class Command::GoToUserTest < ActionDispatch::IntegrationTest
+  include CommandTestHelper
+
+  test "redirects to the user perma" do
+    result = execute_command "@kevin"
+
+    assert_equal users(:kevin), result.url
+  end
+
+  test "results in an invalid command if the user does not exist" do
+    command = parse_command "@not_a_user"
+    assert !command.valid?
+  end
+end
diff --git a/test/models/command/parser_test.rb b/test/models/command/parser_test.rb
new file mode 100644
index 000000000..c4d442dee
--- /dev/null
+++ b/test/models/command/parser_test.rb
@@ -0,0 +1 @@
+# The parser is tested through the tests of specific commands. See +Command::AssignTests+, etc.
diff --git a/test/models/command/search_test.rb b/test/models/command/search_test.rb
new file mode 100644
index 000000000..11476620d
--- /dev/null
+++ b/test/models/command/search_test.rb
@@ -0,0 +1,17 @@
+require "test_helper"
+
+class Command::SearchTest < ActionDispatch::IntegrationTest
+  include CommandTestHelper
+
+  test "redirects to the cards index filtering by search terms" do
+    result = execute_command "some text"
+
+    assert_equal cards_path(indexed_by: "newest", terms: [ "some text" ]), result.url
+  end
+
+  test "respects existing filters" do
+    result = execute_command "some text", context_url: "http://37signals.fizzy.localhost:3006/cards?collection_ids%5B%5D=#{collections(:writebook).id}"
+
+    assert_equal cards_path(indexed_by: "newest", collection_ids: [collections(:writebook).id], terms: [ "some text" ]), result.url
+  end
+end
diff --git a/test/test_helpers/command_test_helper.rb b/test/test_helpers/command_test_helper.rb
new file mode 100644
index 000000000..a0d760e8b
--- /dev/null
+++ b/test/test_helpers/command_test_helper.rb
@@ -0,0 +1,13 @@
+module CommandTestHelper
+  def execute_command(string, context_url: nil, user: users(:david))
+    parse_command(string, context_url: context_url, user: user).execute
+  end
+
+  def parse_command(string, context_url: nil, user: users(:david))
+    context = Command::Parser::Context.new(user, url: context_url)
+    parser = Command::Parser.new(context)
+    parser.parse(string).tap do |command|
+      command.user = user if command
+    end
+  end
+end