don't send telemetry event indicating empty coverage for skipped tests

lib/datadog/ci/test_optimisation/component.rb

@@ -109,13 +109,15 @@ def stop_coverage(test)
           Telemetry.code_coverage_finished(test)
 
           coverage = coverage_collector&.stop
+
+          # if test was skipped, we discard coverage data
+          return if test.skipped?
+
           if coverage.nil? || coverage.empty?
             Telemetry.code_coverage_is_empty
             return
           end
 
-          return if test.skipped?
-
           test_source_file = test.source_file
 
           # cucumber's gherkin files are not covered by the code coverage collector

spec/datadog/ci/test_optimisation/component_spec.rb

@@ -235,6 +235,24 @@
         expect(subject).to be_nil
         expect(writer).not_to have_received(:write)
       end
+
+      it_behaves_like "emits no metric", :inc, Datadog::CI::Ext::Telemetry::METRIC_CODE_COVERAGE_IS_EMPTY
+    end
+
+    context "when test is skipped and coverage is empty" do
+      before do
+        allow_any_instance_of(Datadog::CI::TestOptimisation::Coverage::DDCov).to receive(:stop).and_return(nil)
+
+        component.start_coverage(test_span)
+        test_span.skipped!
+      end
+
+      it "does not write coverage event" do
+        expect(subject).to be_nil
+        expect(writer).not_to have_received(:write)
+      end
+
+      it_behaves_like "emits no metric", :inc, Datadog::CI::Ext::Telemetry::METRIC_CODE_COVERAGE_IS_EMPTY
     end
 
     context "when coverage was not collected" do