1 files changed, 46 insertions, 0 deletions
diff --git a/spec/mspec/lib/mspec/helpers/argv.rb b/spec/mspec/lib/mspec/helpers/argv.rb
new file mode 100644
index 0000000000..c8cbbf2ac3
--- /dev/null
+++ b/spec/mspec/lib/mspec/helpers/argv.rb
@@ -0,0 +1,46 @@
+class Object
+  # Convenience helper for altering ARGV. Saves the
+  # value of ARGV and sets it to +args+. If a block
+  # is given, yields to the block and then restores
+  # the value of ARGV. The previously saved value of
+  # ARGV can be restored by passing +:restore+. The
+  # former is useful in a single spec. The latter is
+  # useful in before/after actions. For example:
+  #
+  #   describe "This" do
+  #     before do
+  #       argv ['a', 'b']
+  #     end
+  #
+  #     after do
+  #       argv :restore
+  #     end
+  #
+  #     it "does something" do
+  #       # do something
+  #     end
+  #   end
+  #
+  #   describe "That" do
+  #     it "does something" do
+  #       argv ['a', 'b'] do
+  #         # do something
+  #       end
+  #     end
+  #   end
+  def argv(args)
+    if args == :restore
+      ARGV.replace(@__mspec_saved_argv__ || [])
+    else
+      @__mspec_saved_argv__ = ARGV.dup
+      ARGV.replace args
+      if block_given?
+        begin
+          yield
+        ensure
+          argv :restore
+        end
+      end
+    end
+  end
+end