Increase test coverage. We now have 100% C0 coverage.

Signed-off-by: Coda Hale <coda.hale@gmail.com>

spec/bcrypt/engine_spec.rb

@@ -29,6 +29,10 @@
 
 context "Generating BCrypt hashes" do
 
+  class MyInvalidSecret
+    undef to_s
+  end
+
   before :each do
     @salt = BCrypt::Engine.generate_salt(4)
     @password = "woo"
@@ -43,10 +47,15 @@
   end
 
   specify "should raise an InvalidSecret error if the secret is invalid" do
+    lambda { BCrypt::Engine.hash_secret(MyInvalidSecret.new, @salt) }.should raise_error(BCrypt::Errors::InvalidSecret)
     lambda { BCrypt::Engine.hash_secret(nil, @salt) }.should_not raise_error(BCrypt::Errors::InvalidSecret)
     lambda { BCrypt::Engine.hash_secret(false, @salt) }.should_not raise_error(BCrypt::Errors::InvalidSecret)
   end
 
+  specify "should call #to_s on the secret and use the return value as the actual secret data" do
+    BCrypt::Engine.hash_secret(false, @salt).should == BCrypt::Engine.hash_secret("false", @salt)
+  end
+
   specify "should be interoperable with other implementations" do
     # test vectors from the OpenWall implementation <http://www.openwall.com/crypt/>
     test_vectors = [