Remove an unecessary double and clean up some syntax

spec/lib/gitlab/badge/coverage/report_spec.rb

@@ -51,10 +51,8 @@ RSpec.describe Gitlab::Badge::Coverage::Report do
     end
 
     context 'with no job specified' do
-      let(:pipeline) { double('pipeline', coverage: 1) }
-
       it 'returns the pipeline coverage value' do
-        expect(badge.status).to eq(1.00)
+        expect(badge.status).to eq(50.00)
       end
     end
 
@@ -62,14 +60,14 @@ RSpec.describe Gitlab::Badge::Coverage::Report do
       let(:job_name) { 'incorrect name' }
 
       it 'returns nil' do
-        expect(badge.status).to eq(nil)
+        expect(badge.status).to be_nil
       end
     end
 
     context 'with a matching job name specified' do
       let(:job_name) { 'first' }
 
-      it 'returns nil' do
+      it 'returns the pipeline coverage value' do
         expect(badge.status).to eq(40.00)
       end
     end