dashboard/app: slightly improve coverage report wording

dashboard/app/reporting_email.go

@@ -169,6 +169,7 @@ func sendNsCoverageReport(ctx context.Context, ns, email string,
 	if err != nil {
 		return fmt.Errorf("coverageTable: %w", err)
 	}
+	cfg := getNsConfig(ctx, ns)
 	args := struct {
 		Namespace      string
 		PeriodFrom     string
@@ -178,7 +179,7 @@ func sendNsCoverageReport(ctx context.Context, ns, email string,
 		Link           string
 		Table          string
 	}{
-		Namespace:      ns,
+		Namespace:      cfg.DisplayTitle,
 		PeriodFrom:     periodFrom,
 		PeriodFromDays: period[0].Days,
 		PeriodTo:       periodTo,
@@ -187,7 +188,7 @@ func sendNsCoverageReport(ctx context.Context, ns, email string,
 			coveragePageLink(ns, period[1].Type, period[1].DateTo.String(), minDrop, 2, true)),
 		Table: table,
 	}
-	title := fmt.Sprintf("%s coverage regression in %s", ns, periodTo)
+	title := fmt.Sprintf("%s coverage regressions in %s", cfg.DisplayTitle, periodTo)
 	err = sendMailTemplate(ctx, &mailSendParams{
 		templateName: "mail_ns_coverage.txt",
 		templateArg:  args,

dashboard/app/reporting_test.go

@@ -1406,10 +1406,10 @@ func TestCoverageRegression(t *testing.T) {
 	assert.Equal(t, 1, len(c.emailSink))
 	msg := <-c.emailSink
 	assert.Equal(t, []string{"test@test.test"}, msg.To)
-	assert.Equal(t, "coverage-tests coverage regression in December 1999", msg.Subject)
+	assert.Equal(t, "coverage-tests coverage regressions in December 1999", msg.Subject)
 	wantLink := "https://testapp.appspot.com/coverage-tests/coverage?" +
 		"dateto=1999-12-31&min-cover-lines-drop=1&order-by-cover-lines-drop=1&period=month&period_count=2"
-	assert.Equal(t, `Regressions happened in 'coverage-tests' from November 1999 (30 days) to December 1999 (31 days).
+	assert.Equal(t, `coverage-tests regressions in December 1999 (31 days) since November 1999 (30 days).
 Web version: `+wantLink+`
 
 Blocks diff,	Path

dashboard/app/templates/mail_ns_coverage.txt

@@ -1,4 +1,4 @@
-Regressions happened in '{{.Namespace}}' from {{.PeriodFrom}} ({{.PeriodFromDays}} days) to {{.PeriodTo}} ({{.PeriodToDays}} days).
+{{.Namespace}} regressions in {{.PeriodTo}} ({{.PeriodToDays}} days) since {{.PeriodFrom}} ({{.PeriodFromDays}} days).
 Web version: {{.Link}}
 
 {{.Table}}