Enhance Tender entity with PublicationSubmissionDeadline method and corresponding tests

- Added the PublicationSubmissionDeadline method to the Tender entity, which calculates the submission deadline based on the publication date and stored submission deadline.
- Updated the IsRecommendable method to utilize the new PublicationSubmissionDeadline logic for determining recommendation eligibility.
- Introduced unit tests for the PublicationSubmissionDeadline method, ensuring accurate calculation and validation of submission deadlines.
- Enhanced existing tests for the IsRecommendable method to cover new scenarios related to submission deadlines.

This update improves the accuracy of submission deadline handling and enhances the recommendation logic for tenders based on publication dates.

internal/tender/entity_test.go

@@ -73,6 +73,21 @@ func TestResolvedEstimatedValueAndCurrencyPrefersTopLevel(t *testing.T) {
 	}
 }
 
+func TestTenderPublicationSubmissionDeadline(t *testing.T) {
+	pubDate := int64(1_700_000_000)
+	tender := Tender{PublicationDate: pubDate}
+
+	got := tender.PublicationSubmissionDeadline()
+	if got <= pubDate {
+		t.Fatalf("expected submission deadline after publication_date, got %d (publication_date=%d)", got, pubDate)
+	}
+
+	withStored := Tender{PublicationDate: pubDate, SubmissionDeadline: pubDate + 999}
+	if deadline := withStored.PublicationSubmissionDeadline(); deadline != pubDate+999 {
+		t.Fatalf("expected stored submission_deadline, got %d", deadline)
+	}
+}
+
 func TestTenderIsRecommendable(t *testing.T) {
 	now := int64(1_700_000_000)
 
@@ -82,33 +97,48 @@ func TestTenderIsRecommendable(t *testing.T) {
 		want   bool
 	}{
 		{
-			name:   "active with future deadline",
-			tender: Tender{Status: TenderStatusActive, TenderDeadline: now + 3600},
+			name:   "active with future submission deadline",
+			tender: Tender{Status: TenderStatusActive, SubmissionDeadline: now + 3600},
 			want:   true,
 		},
 		{
-			name:   "active with past deadline",
-			tender: Tender{Status: TenderStatusActive, TenderDeadline: now - 3600},
+			name:   "active with past submission deadline",
+			tender: Tender{Status: TenderStatusActive, SubmissionDeadline: now - 3600},
 			want:   false,
 		},
 		{
-			name:   "active with deadline at now",
-			tender: Tender{Status: TenderStatusActive, TenderDeadline: now},
+			name:   "active with future tender deadline but past submission deadline",
+			tender: Tender{Status: TenderStatusActive, TenderDeadline: now + 86400, SubmissionDeadline: now - 3600},
 			want:   false,
 		},
 		{
-			name:   "active without deadline",
-			tender: Tender{Status: TenderStatusActive, TenderDeadline: 0},
+			name:   "active with future tender deadline only",
+			tender: Tender{Status: TenderStatusActive, TenderDeadline: now + 86400},
 			want:   false,
 		},
 		{
-			name:   "expired status with future deadline",
-			tender: Tender{Status: TenderStatusExpired, TenderDeadline: now + 3600},
+			name:   "active with submission deadline at now",
+			tender: Tender{Status: TenderStatusActive, SubmissionDeadline: now},
 			want:   false,
 		},
 		{
-			name:   "awarded with future deadline",
-			tender: Tender{Status: TenderStatusAwarded, TenderDeadline: now + 3600},
+			name:   "active without publication or submission deadline",
+			tender: Tender{Status: TenderStatusActive},
+			want:   false,
+		},
+		{
+			name:   "active with publication date only and open submission window",
+			tender: Tender{Status: TenderStatusActive, PublicationDate: now - 3600},
+			want:   true,
+		},
+		{
+			name:   "expired status with future submission deadline",
+			tender: Tender{Status: TenderStatusExpired, SubmissionDeadline: now + 3600},
+			want:   false,
+		},
+		{
+			name:   "awarded with future submission deadline",
+			tender: Tender{Status: TenderStatusAwarded, SubmissionDeadline: now + 3600},
 			want:   false,
 		},
 	}