match query times with appropriate delta

spec/lib/gitlab/prometheus/queries/deployment_query_spec.rb

@@ -12,22 +12,23 @@ describe Gitlab::Prometheus::Queries::DeploymentQuery, lib: true do
   end
 
   it 'sends appropriate queries to prometheus' do
-    start_time = (deployment.created_at - 30.minutes).to_f
+    start_time_matcher = be_within(0.5).of((deployment.created_at - 30.minutes).to_f)
+    stop_time_matcher = be_within(0.5).of((deployment.created_at + 30.minutes).to_f)
+    created_at_matcher = be_within(0.5).of(deployment.created_at.to_f)
 
-    stop_time = (deployment.created_at + 30.minutes).to_f
     expect(client).to receive(:query_range).with('avg(container_memory_usage_bytes{container_name!="POD",environment="environment-slug"}) / 2^20',
-                                                 start: start_time, stop: stop_time)
+                                                 start: start_time_matcher, stop: stop_time_matcher)
     expect(client).to receive(:query).with('avg(avg_over_time(container_memory_usage_bytes{container_name!="POD",environment="environment-slug"}[30m]))',
-                                           time: deployment.created_at.to_f)
+                                           time: created_at_matcher)
     expect(client).to receive(:query).with('avg(avg_over_time(container_memory_usage_bytes{container_name!="POD",environment="environment-slug"}[30m]))',
-                                           time: stop_time)
+                                           time: stop_time_matcher)
 
     expect(client).to receive(:query_range).with('avg(rate(container_cpu_usage_seconds_total{container_name!="POD",environment="environment-slug"}[2m])) * 100',
-                                                 start: start_time, stop: stop_time)
+                                                 start: start_time_matcher, stop: stop_time_matcher)
     expect(client).to receive(:query).with('avg(rate(container_cpu_usage_seconds_total{container_name!="POD",environment="environment-slug"}[30m])) * 100',
-                                           time: deployment.created_at.to_f)
+                                           time: created_at_matcher)
     expect(client).to receive(:query).with('avg(rate(container_cpu_usage_seconds_total{container_name!="POD",environment="environment-slug"}[30m])) * 100',
-                                           time: stop_time)
+                                           time: stop_time_matcher)
 
     expect(subject.query(deployment.id)).to eq(memory_values: nil, memory_before: nil, memory_after: nil,
                                                cpu_values: nil, cpu_before: nil, cpu_after: nil)