Adds changes from @tkuah review

- Adds a spec for filtering by confidence
- Updates the occourence spec to remove the magic number

ee/spec/finders/security/vulnerabilities_finder_spec.rb

@@ -10,8 +10,8 @@
     set(:pipeline1) { create(:ci_pipeline, :success, project: project1) }
     set(:pipeline2) { create(:ci_pipeline, :success, project: project2) }
 
-    set(:vulnerability1) { create(:vulnerabilities_occurrence, report_type: :sast, severity: :high, pipelines: [pipeline1], project: project1) }
-    set(:vulnerability2) { create(:vulnerabilities_occurrence, report_type: :dependency_scanning, severity: :medium, pipelines: [pipeline2], project: project2) }
+    set(:vulnerability1) { create(:vulnerabilities_occurrence, report_type: :sast, severity: :high, confidence: :high, pipelines: [pipeline1], project: project1) }
+    set(:vulnerability2) { create(:vulnerabilities_occurrence, report_type: :dependency_scanning, severity: :medium, confidence: :low, pipelines: [pipeline2], project: project2) }
     set(:vulnerability3) { create(:vulnerabilities_occurrence, report_type: :sast, severity: :low, pipelines: [pipeline2], project: project2) }
     set(:vulnerability4) { create(:vulnerabilities_occurrence, report_type: :dast, severity: :medium, pipelines: [pipeline1], project: project1) }
 
@@ -53,6 +53,24 @@
       end
     end
 
+    context 'by confidence' do
+      context 'when high' do
+        let(:params) { { confidence: %w[high] } }
+
+        it 'includes only high confidence vulnerabilities' do
+          is_expected.to contain_exactly(vulnerability1)
+        end
+      end
+
+      context 'when low' do
+        let(:params) { { confidence: %w[low] } }
+
+        it 'includes only low confidence vulnerabilities' do
+          is_expected.to contain_exactly(vulnerability2)
+        end
+      end
+    end
+
     context 'by project' do
       let(:params) { { project_id: [project2.id] } }
 

ee/spec/models/vulnerabilities/occurrence_spec.rb

@@ -218,7 +218,7 @@
     subject { described_class.by_severities(param) }
 
     context 'with one param' do
-      let(:param) { 4 }
+      let(:param) { described_class.severities[:low] }
 
       it 'returns found record' do
         is_expected.to contain_exactly(vulnerability_low)
@@ -226,7 +226,7 @@
     end
 
     context 'without found record' do
-      let(:param) { 7 }
+      let(:param) { described_class.severities[:unknown] }
 
       it 'returns empty collection' do
         is_expected.to be_empty
@@ -240,16 +240,16 @@
 
     subject { described_class.by_confidences(param) }
 
-    context 'with one param' do
-      let(:param) { 4 }
+    context 'with matching param' do
+      let(:param) { described_class.confidences[:low] }
 
       it 'returns found record' do
         is_expected.to contain_exactly(vulnerability_low)
       end
     end
 
-    context 'without found record' do
-      let(:param) { 7 }
+    context 'with non-matching param' do
+      let(:param) { described_class.confidences[:unknown] }
 
       it 'returns empty collection' do
         is_expected.to be_empty