mutant exception example

gistfile1.rb

# foo.rb
def foo
  @db = PStore.new(data_file)
rescue PStore::Error
  raise DatabaseError.new("Database directory #{data_file} does not exist")
end

# foo_spec.rb
describe "#foo" do
  it "should raise an error when database directory is inaccessible" do
    expect { Database.new(nonexistent_dir) }.to raise_error(DatabaseError, 
                                                            "Database directory #{nonexistent_dir} does not exist")
  end
end

mutant.diff

-rescue PStore::Error
+rescue