Allow nil commit author and message

It should fix [integrity#132].

lib/integrity/commit.rb

@@ -21,7 +21,8 @@ def message
     end
 
     def author
-      attribute_get(:author) || Author.load('<Commit author not loaded> <<Commit author not loaded>>', :author)
+      attribute_get(:author) ||
+        Author.load('<Commit author not loaded> <<Commit author not loaded>>', :author)
     end
 
     def short_identifier

lib/integrity/migrations.rb

@@ -84,8 +84,8 @@ class ::Integrity::Build
         create_table :integrity_commits do
           column :id,           Integer,  :serial => true
           column :identifier,   String,   :nullable => false
-          column :message,      String,   :nullable => false, :length => 255
-          column :author,       String,   :nullable => false, :length => 255
+          column :message,      String,   :nullable => true, :length => 255
+          column :author,       String,   :nullable => true, :length => 255
           column :committed_at, DateTime, :nullable => false
           column :created_at,  DateTime
           column :updated_at,  DateTime

test/unit/commit_test.rb

@@ -32,6 +32,8 @@ class CommitTest < Test::Unit::TestCase
       commit.author.name.should == "Nicolás Sanguinetti"
       commit.author.email.should == "contacto@nicolassanguinetti.info"
       commit.author.full.should == "Nicolás Sanguinetti <contacto@nicolassanguinetti.info>"
+
+      Commit.gen(:author => nil).author.to_s.should =~ /not loaded/
     end
 
     it "raises ArgumentError with invalid author" do
@@ -41,6 +43,8 @@ class CommitTest < Test::Unit::TestCase
     it "has a commit message" do
       commit = Commit.gen(:message => "This commit rocks")
       commit.message.should == "This commit rocks"
+
+      Commit.gen(:message => nil).message.should =~ /not loaded/
     end
 
     it "has a commit date" do

test/unit/project_test.rb

@@ -352,13 +352,12 @@ class ProjectTest < Test::Unit::TestCase
       }.should change(Commit, :count).by(1)
 
       build = Build.all.last
-      build.commit.should be(@project.last_commit)
+      build.commit.should == @project.last_commit
 
       @project.last_commit.should be_pending
-      @project.last_commit.identifier.should be("FOOBAR")
-
+      @project.last_commit.identifier.should  == "FOOBAR"
       @project.last_commit.author.name.should == "<Commit author not loaded>"
-      @project.last_commit.message.should == "<Commit message not loaded>"
+      @project.last_commit.message.should     == "<Commit message not loaded>"
     end
   end
 end