diff --git a/config/environments/test.rb b/config/environments/test.rb
index 4a01914e6..3f79b3b0f 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -63,9 +63,9 @@ Rails.application.configure do
 
   # Annotate rendered view with file names.
   # config.action_view.annotate_rendered_view_with_filenames = true
-  config.action_mailer.default_url_options = { :host => 'localhost:3000' }
+  config.action_mailer.default_url_options = { host: ENV.fetch("APP_HOST") }
   Rails.application.routes.default_url_options = {
-    host: 'localhost:3000',
+    host: ENV.fetch("APP_HOST"),
     protocol: :http
   }
 
diff --git a/spec/models/concern/mail_template_concern_spec.rb b/spec/models/concern/mail_template_concern_spec.rb
index e33adb3d2..965d8432f 100644
--- a/spec/models/concern/mail_template_concern_spec.rb
+++ b/spec/models/concern/mail_template_concern_spec.rb
@@ -25,7 +25,7 @@ describe MailTemplateConcern do
       it do
         expected =
           "[demarches-simplifiees.fr] #{dossier.id} #{dossier.procedure.libelle} " +
-          "<a target=\"_blank\" rel=\"noopener\" href=\"http://localhost:3000/dossiers/#{dossier.id}\">http://localhost:3000/dossiers/#{dossier.id}</a>"
+          "<a target=\"_blank\" rel=\"noopener\" href=\"http://test.host/dossiers/#{dossier.id}\">http://test.host/dossiers/#{dossier.id}</a>"
 
         is_expected.to eq(expected)
       end
@@ -75,7 +75,7 @@ describe MailTemplateConcern do
 
       describe "in closed mail without justificatif" do
         let(:mail) { create(:closed_mail, procedure: procedure) }
-        it { is_expected.to eq("<a target=\"_blank\" rel=\"noopener\" href=\"http://localhost:3000/dossiers/#{dossier.id}/attestation\">http://localhost:3000/dossiers/#{dossier.id}/attestation</a>") }
+        it { is_expected.to eq("<a target=\"_blank\" rel=\"noopener\" href=\"http://test.host/dossiers/#{dossier.id}/attestation\">http://test.host/dossiers/#{dossier.id}/attestation</a>") }
         it { is_expected.to_not include("Télécharger le justificatif") }
       end
 
@@ -86,7 +86,7 @@ describe MailTemplateConcern do
         let(:mail) { create(:closed_mail, procedure: procedure) }
 
         it { expect(dossier.justificatif_motivation).to be_attached }
-        it { is_expected.to include("<a target=\"_blank\" rel=\"noopener\" href=\"http://localhost:3000/dossiers/#{dossier.id}/attestation\">http://localhost:3000/dossiers/#{dossier.id}/attestation</a>") }
+        it { is_expected.to include("<a target=\"_blank\" rel=\"noopener\" href=\"http://test.host/dossiers/#{dossier.id}/attestation\">http://test.host/dossiers/#{dossier.id}/attestation</a>") }
         it { is_expected.to_not include("Télécharger le justificatif") }
       end
 
diff --git a/spec/serializers/procedure_serializer_spec.rb b/spec/serializers/procedure_serializer_spec.rb
index 55eeaa000..919bf53ee 100644
--- a/spec/serializers/procedure_serializer_spec.rb
+++ b/spec/serializers/procedure_serializer_spec.rb
@@ -4,7 +4,7 @@ describe ProcedureSerializer do
     let(:procedure) { create(:procedure, :published) }
 
     it {
-      is_expected.to include(link: "http://localhost:3000/commencer/#{procedure.path}")
+      is_expected.to include(link: "http://test.host/commencer/#{procedure.path}")
       is_expected.to include(state: "publiee")
     }
   end